victauri_plugin/mcp/

mod.rs

// This file is intentionally large (~3,400 lines). rmcp's `#[tool_router]`
// macro requires every `#[tool]` method to live in a single `impl` block, so
// splitting the handler across files would break tool registration. Parameter
// structs are already factored into sub-modules (webview_params, window_params,
// etc.) to keep this file focused on dispatch logic.

mod backend_params;
mod compound_params;
mod helpers;
mod introspection_params;
mod other_params;
mod rest;
mod server;
mod verification_params;
mod webview_params;
mod window_params;

use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};

use rmcp::handler::server::tool::ToolCallContext;
use rmcp::handler::server::wrapper::Parameters;
use rmcp::model::{
    AnnotateAble, CallToolRequestParams, CallToolResult, Content, ListResourcesResult,
    ListToolsResult, PaginatedRequestParams, RawContent, RawResource, ReadResourceRequestParams,
    ReadResourceResult, ResourceContents, ServerCapabilities, ServerInfo, SubscribeRequestParams,
    Tool, UnsubscribeRequestParams,
};
use rmcp::service::RequestContext;
use rmcp::{ErrorData, RoleServer, ServerHandler, tool, tool_router};
use tokio::sync::Mutex;

use crate::VictauriState;
use crate::bridge::WebviewBridge;

use helpers::{
    RecoveryHint, js_string, json_result, missing_param, sanitize_css_color, tool_disabled,
    tool_error, tool_error_with_hint, validate_url,
};

pub use backend_params::*;
pub use compound_params::*;
pub use introspection_params::*;
pub use other_params::{
    DiagnosticsParams, FindElementsParams, ResolveCommandParams, SemanticAssertParams,
    WaitCondition, WaitForParams,
};
pub use server::*;
pub use verification_params::*;
pub use webview_params::*;
pub use window_params::*;

// ── MCP Handler ──────────────────────────────────────────────────────────────

/// Maximum number of in-flight JavaScript eval requests. Prevents unbounded
/// growth of the `pending_evals` map if callbacks are never resolved.
pub(crate) const MAX_PENDING_EVALS: usize = 100;

fn chrono_now() -> String {
    chrono::Utc::now().to_rfc3339_opts(chrono::SecondsFormat::Secs, true)
}

/// Maximum length of JavaScript code accepted by the `eval_js` tool (1 MB).
const MAX_EVAL_CODE_LEN: usize = 1_000_000;

/// Maximum length of a JavaScript eval return value (5 MB).
/// Results exceeding this are truncated to prevent memory exhaustion.
const MAX_EVAL_RESULT_LEN: usize = 5_000_000;

/// Default number of entries returned by IPC/network log tools when no explicit
/// `limit` is given. Prevents busy apps (large logs) from exceeding the eval cap.
const DEFAULT_LOG_LIMIT: usize = 100;

/// Per-field byte cap applied to each IPC/network log entry before serialization.
/// Large request/response bodies are truncated with a marker so the aggregate
/// log stays well under [`MAX_EVAL_RESULT_LEN`] even on heavy-traffic apps.
const MAX_LOG_FIELD_BYTES: usize = 4096;

const RESOURCE_URI_IPC_LOG: &str = "victauri://ipc-log";
const RESOURCE_URI_WINDOWS: &str = "victauri://windows";
const RESOURCE_URI_STATE: &str = "victauri://state";

const BRIDGE_VERSION: &str = "0.5.0";

const SAFE_ENV_PREFIXES: &[&str] = &[
    "HOME",
    "USER",
    "LANG",
    "LC_",
    "TERM",
    "SHELL",
    "DISPLAY",
    "XDG_",
    "TAURI_",
    "VICTAURI_",
    "NODE_ENV",
    "OS",
    "HOSTNAME",
    "PWD",
    "SHLVL",
    "LOGNAME",
];

/// MCP tool handler that dispatches tool calls to the webview bridge and state.
#[derive(Clone)]
pub struct VictauriMcpHandler {
    state: Arc<VictauriState>,
    bridge: Arc<dyn WebviewBridge>,
    subscriptions: Arc<Mutex<HashSet<String>>>,
    bridge_checked: Arc<AtomicBool>,
    probed_labels: Arc<Mutex<HashSet<String>>>,
}

#[tool_router]
impl VictauriMcpHandler {
    // ── Standalone Tools ────────────────────────────────────────────────────

    #[tool(
        description = "Evaluate JavaScript in the Tauri webview and return the result. Async expressions are wrapped automatically.",
        annotations(
            read_only_hint = false,
            destructive_hint = true,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn eval_js(&self, Parameters(params): Parameters<EvalJsParams>) -> CallToolResult {
        if !self.state.privacy.is_tool_enabled("eval_js") {
            return tool_disabled("eval_js");
        }
        if params.code.len() > MAX_EVAL_CODE_LEN {
            return tool_error("code exceeds maximum length (1 MB)");
        }
        match self
            .eval_with_return(&params.code, params.webview_label.as_deref())
            .await
        {
            Ok(result) => CallToolResult::success(vec![Content::text(result)]),
            Err(e) => tool_error(e),
        }
    }

    #[tool(
        description = "Get the DOM snapshot with stable ref handles. Default: compact accessible text (70-80%% fewer tokens). Set format=\"json\" for full tree. Returns tree + stale_refs (refs invalidated since last snapshot).",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn dom_snapshot(&self, Parameters(params): Parameters<SnapshotParams>) -> CallToolResult {
        let format = params.format.unwrap_or(SnapshotFormat::Compact);
        let format_str = match format {
            SnapshotFormat::Compact => "compact",
            SnapshotFormat::Json => "json",
        };
        let code = format!(
            "return window.__VICTAURI__?.snapshot({})",
            js_string(format_str)
        );
        self.eval_bridge(&code, params.webview_label.as_deref())
            .await
    }

    #[tool(
        description = "Search for elements by text, role, test_id, CSS selector (via `css` or `selector` param), or accessible name without a full snapshot. Returns lightweight matches with ref handles.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn find_elements(
        &self,
        Parameters(params): Parameters<FindElementsParams>,
    ) -> CallToolResult {
        let mut parts: Vec<String> = Vec::new();
        if let Some(t) = &params.text {
            parts.push(format!("text: {}", js_string(t)));
        }
        if let Some(r) = &params.role {
            parts.push(format!("role: {}", js_string(r)));
        }
        if let Some(tid) = &params.test_id {
            parts.push(format!("test_id: {}", js_string(tid)));
        }
        if let Some(c) = params.css.as_ref().or(params.selector.as_ref()) {
            parts.push(format!("css: {}", js_string(c)));
        }
        if let Some(n) = &params.name {
            parts.push(format!("name: {}", js_string(n)));
        }
        if let Some(max) = params.max_results {
            parts.push(format!("max_results: {max}"));
        }
        if let Some(t) = &params.tag {
            parts.push(format!("tag: {}", js_string(t)));
        }
        if let Some(p) = &params.placeholder {
            parts.push(format!("placeholder: {}", js_string(p)));
        }
        if let Some(a) = &params.alt {
            parts.push(format!("alt: {}", js_string(a)));
        }
        if let Some(ta) = &params.title_attr {
            parts.push(format!("title_attr: {}", js_string(ta)));
        }
        if let Some(l) = &params.label {
            parts.push(format!("label: {}", js_string(l)));
        }
        if let Some(true) = params.exact {
            parts.push("exact: true".to_string());
        }
        if let Some(e) = params.enabled {
            parts.push(format!("enabled: {e}"));
        }
        let code = format!(
            "return window.__VICTAURI__?.findElements({{ {} }})",
            parts.join(", ")
        );
        match self
            .eval_with_return(&code, params.webview_label.as_deref())
            .await
        {
            Ok(result) => {
                if let Ok(parsed) = serde_json::from_str::<serde_json::Value>(&result)
                    && let Some(err) = parsed.get("error").and_then(|e| e.as_str())
                {
                    return tool_error(err);
                }
                CallToolResult::success(vec![Content::text(result)])
            }
            Err(e) => tool_error(e),
        }
    }

    #[tool(
        description = "Invoke a registered Tauri command via IPC, just like the frontend would. Goes through the real IPC pipeline so calls are logged and verifiable. Returns the command's result. Subject to privacy command filtering.",
        annotations(
            read_only_hint = false,
            destructive_hint = true,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn invoke_command(
        &self,
        Parameters(params): Parameters<InvokeCommandParams>,
    ) -> CallToolResult {
        if !self.state.privacy.is_invoke_allowed(&params.command) {
            return tool_disabled("invoke_command");
        }
        if !self.state.privacy.is_command_allowed(&params.command) {
            return tool_error(format!(
                "command '{}' is blocked by privacy configuration",
                params.command
            ));
        }

        // ── Fault injection check ──
        if let Some(fault) = self.state.fault_registry.check_and_trigger(&params.command) {
            match fault {
                crate::introspection::FaultType::Delay { delay_ms } => {
                    tracing::info!(
                        command = %params.command,
                        delay_ms = delay_ms,
                        "fault injection: delaying command"
                    );
                    tokio::time::sleep(std::time::Duration::from_millis(delay_ms)).await;
                    // After delay, continue with normal execution below
                }
                crate::introspection::FaultType::Error { ref message } => {
                    tracing::info!(
                        command = %params.command,
                        "fault injection: returning error"
                    );
                    return tool_error(format!(
                        "[FAULT INJECTED] command '{}': {message}",
                        params.command
                    ));
                }
                crate::introspection::FaultType::Drop => {
                    tracing::info!(
                        command = %params.command,
                        "fault injection: dropping response"
                    );
                    return CallToolResult::success(vec![Content::text("{}")]);
                }
                crate::introspection::FaultType::Corrupt => {
                    tracing::info!(
                        command = %params.command,
                        "fault injection: corrupting response"
                    );
                    // Execute normally but mangle the response
                    let args_json = params.args.unwrap_or(serde_json::json!({}));
                    let args_str =
                        serde_json::to_string(&args_json).unwrap_or_else(|_| "{}".to_string());
                    let code = format!(
                        "return window.__TAURI_INTERNALS__.invoke({}, {args_str})",
                        js_string(&params.command)
                    );
                    if let Ok(result) = self
                        .eval_with_return(&code, params.webview_label.as_deref())
                        .await
                    {
                        let corrupted = format!(
                            "{{\"__corrupted\":true,\"original_length\":{},\"fault\":\"corrupt\"}}",
                            result.len()
                        );
                        return CallToolResult::success(vec![Content::text(corrupted)]);
                    }
                    return CallToolResult::success(vec![Content::text(
                        "{\"__corrupted\":true,\"fault\":\"corrupt\",\"note\":\"original invocation also failed\"}",
                    )]);
                }
            }
        }

        // ── Normal execution with timing ──
        let start = std::time::Instant::now();
        let args_json = params.args.unwrap_or(serde_json::json!({}));
        let args_str = serde_json::to_string(&args_json).unwrap_or_else(|_| "{}".to_string());
        let code = format!(
            "return window.__TAURI_INTERNALS__.invoke({}, {args_str})",
            js_string(&params.command)
        );
        let result = self
            .eval_with_return(&code, params.webview_label.as_deref())
            .await;
        let elapsed = start.elapsed();
        self.state.command_timings.record(&params.command, elapsed);

        match result {
            Ok(result) => {
                if let Ok(parsed) = serde_json::from_str::<serde_json::Value>(&result)
                    && let Some(err) = parsed.get("__error").and_then(|e| e.as_str())
                {
                    return tool_error(format!(
                        "command '{}' returned error: {err}",
                        params.command
                    ));
                }
                CallToolResult::success(vec![Content::text(result)])
            }
            Err(e) => tool_error(format!("invoke_command failed: {e}")),
        }
    }

    #[tool(
        description = "Capture a screenshot of a Tauri window as a base64-encoded PNG image. Works on Windows (PrintWindow), macOS (CGWindowListCreateImage), and Linux (X11/Wayland).",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn screenshot(&self, Parameters(params): Parameters<ScreenshotParams>) -> CallToolResult {
        self.track_tool_call();
        if !self.state.privacy.is_tool_enabled("screenshot") {
            return tool_disabled("screenshot");
        }
        match self
            .bridge
            .get_native_handle(params.window_label.as_deref())
        {
            Ok(hwnd) => match crate::screenshot::capture_window(hwnd).await {
                Ok(png_bytes) => {
                    use base64::Engine;
                    let b64 = base64::engine::general_purpose::STANDARD.encode(&png_bytes);
                    CallToolResult::success(vec![Content::image(b64, "image/png")])
                }
                Err(e) => tool_error(format!("screenshot capture failed: {e}")),
            },
            Err(e) => tool_error(format!("cannot get window handle: {e}")),
        }
    }

    #[tool(
        description = "Compare frontend state (evaluated via JS expression) against backend state to detect divergences. Returns a VerificationResult with any mismatches.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn verify_state(
        &self,
        Parameters(params): Parameters<VerifyStateParams>,
    ) -> CallToolResult {
        if !self.state.privacy.is_tool_enabled("eval_js") {
            return tool_disabled("verify_state requires eval_js capability");
        }
        let code = format!("return ({})", params.frontend_expr);
        let frontend_json = match self
            .eval_with_return(&code, params.webview_label.as_deref())
            .await
        {
            Ok(result) => result,
            Err(e) => return tool_error(format!("failed to evaluate frontend expression: {e}")),
        };

        let frontend_state: serde_json::Value = match serde_json::from_str(&frontend_json) {
            Ok(v) => v,
            Err(e) => {
                return tool_error(format!(
                    "frontend expression did not return valid JSON: {e}"
                ));
            }
        };

        let backend_state = if let Some(state) = params.backend_state {
            state
        } else if let Some(ref cmd) = params.backend_command {
            if !self.state.privacy.is_command_allowed(cmd) {
                return tool_error(format!(
                    "command '{cmd}' is blocked by privacy configuration"
                ));
            }
            let args = params.backend_args.unwrap_or(serde_json::json!({}));
            let args_str = serde_json::to_string(&args).unwrap_or_else(|_| "{}".to_string());
            let invoke_code = format!(
                "return window.__TAURI_INTERNALS__.invoke({}, {args_str})",
                js_string(cmd)
            );
            match self
                .eval_with_return(&invoke_code, params.webview_label.as_deref())
                .await
            {
                Ok(result) => match serde_json::from_str(&result) {
                    Ok(v) => v,
                    Err(e) => {
                        return tool_error(format!(
                            "backend command '{cmd}' did not return valid JSON: {e}"
                        ));
                    }
                },
                Err(e) => {
                    return tool_error(format!("failed to invoke backend command '{cmd}': {e}"));
                }
            }
        } else {
            return tool_error("either backend_state or backend_command must be provided");
        };

        let result = victauri_core::verify_state(frontend_state, backend_state);
        json_result(&result)
    }

    #[tool(
        description = "Detect ghost commands — commands invoked from the frontend that have no backend handler, or registered backend commands never called. Reads from the JS-side IPC interception log.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn detect_ghost_commands(
        &self,
        Parameters(params): Parameters<GhostCommandParams>,
    ) -> CallToolResult {
        // Project only command names in JS — ghost detection never needs request
        // or response bodies, so this stays tiny even when the full IPC log is
        // huge (avoids the eval size cap on busy apps).
        let code = "return (window.__VICTAURI__?.getIpcLog() || []).map(function(c){ return (c && c.command) || null; }).filter(function(x){ return x; })";
        let ipc_json = match self
            .eval_with_return(code, params.webview_label.as_deref())
            .await
        {
            Ok(r) => r,
            Err(e) => return tool_error(format!("failed to read IPC log: {e}")),
        };

        let command_names: Vec<String> = match serde_json::from_str(&ipc_json) {
            Ok(v) => v,
            Err(e) => return tool_error(format!("failed to parse IPC log JSON: {e}")),
        };
        let frontend_commands: Vec<String> = command_names
            .into_iter()
            .collect::<std::collections::HashSet<_>>()
            .into_iter()
            .collect();

        let report = victauri_core::detect_ghost_commands(&frontend_commands, &self.state.registry);
        json_result(&report)
    }

    #[tool(
        description = "Check IPC round-trip integrity: find stale (stuck) pending calls and errored calls. Returns health status and lists of problematic IPC calls.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn check_ipc_integrity(
        &self,
        Parameters(params): Parameters<IpcIntegrityParams>,
    ) -> CallToolResult {
        let threshold = params.stale_threshold_ms.unwrap_or(5000);
        let code = format!(
            r"return (function() {{
                var log = window.__VICTAURI__?.getIpcLog() || [];
                var now = Date.now();
                var threshold = {threshold};
                var pending = log.filter(function(c) {{ return c.status === 'pending'; }});
                var stale = pending.filter(function(c) {{ return (now - c.timestamp) > threshold; }});
                var errored = log.filter(function(c) {{ return c.status === 'error'; }});
                var net = window.__VICTAURI__?.getNetworkLog() || [];
                var warning = null;
                if (log.length === 0 && net.length > 5) {{
                    warning = 'Zero IPC calls captured but ' + net.length + ' network requests observed. IPC capture may not be working — verify the app uses Tauri IPC via fetch to ipc.localhost.';
                }}
                return {{
                    healthy: stale.length === 0 && errored.length === 0,
                    total_calls: log.length,
                    pending_count: pending.length,
                    stale_count: stale.length,
                    error_count: errored.length,
                    stale_calls: stale.slice(0, 20),
                    errored_calls: errored.slice(0, 20),
                    warning: warning
                }};
            }})()"
        );
        self.eval_bridge(&code, params.webview_label.as_deref())
            .await
    }

    #[tool(
        description = "Wait for a condition to be met. Polls at regular intervals until satisfied or timeout. Conditions: text (text appears), text_gone (text disappears), selector (CSS selector matches), selector_gone, url (URL contains value), ipc_idle (no pending IPC calls), network_idle (no pending network requests).",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn wait_for(&self, Parameters(params): Parameters<WaitForParams>) -> CallToolResult {
        let value = params
            .value
            .as_ref()
            .map_or_else(|| "null".to_string(), |v| js_string(v));
        let timeout_ms = params.timeout_ms.unwrap_or(10_000).min(60_000);
        let poll = params.poll_ms.unwrap_or(200);
        let code = format!(
            "return window.__VICTAURI__?.waitFor({{ condition: {}, value: {value}, timeout_ms: {timeout_ms}, poll_ms: {poll} }})",
            js_string(params.condition.as_str())
        );
        let eval_timeout = std::time::Duration::from_millis(timeout_ms + 5000);
        match self
            .eval_with_return_timeout(&code, params.webview_label.as_deref(), eval_timeout)
            .await
        {
            Ok(result) => CallToolResult::success(vec![Content::text(result)]),
            Err(e) => tool_error(e),
        }
    }

    #[tool(
        description = "Run a semantic assertion: evaluate a JS expression and check the result against an expected condition. Conditions: equals, not_equals, contains, greater_than, less_than, truthy, falsy, exists, type_is.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn assert_semantic(
        &self,
        Parameters(params): Parameters<SemanticAssertParams>,
    ) -> CallToolResult {
        if !self.state.privacy.is_tool_enabled("eval_js") {
            return tool_disabled("assert_semantic requires eval_js capability");
        }
        let code = format!("return ({})", params.expression);
        let actual_json = match self
            .eval_with_return(&code, params.webview_label.as_deref())
            .await
        {
            Ok(result) => result,
            Err(e) => return tool_error(format!("failed to evaluate expression: {e}")),
        };

        let actual: serde_json::Value = match serde_json::from_str(&actual_json) {
            Ok(v) => v,
            Err(e) => return tool_error(format!("expression did not return valid JSON: {e}")),
        };

        let assertion = victauri_core::SemanticAssertion {
            label: params.label,
            condition: params.condition,
            expected: params.expected,
        };

        let result = victauri_core::evaluate_assertion(actual, &assertion);
        json_result(&result)
    }

    #[tool(
        description = "Resolve a natural language query to matching Tauri commands. Returns scored results ranked by relevance, using command names, descriptions, intents, categories, and examples.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn resolve_command(
        &self,
        Parameters(params): Parameters<ResolveCommandParams>,
    ) -> CallToolResult {
        self.track_tool_call();
        let limit = params.limit.unwrap_or(5);
        let mut results = self.state.registry.resolve(&params.query);
        results.truncate(limit);
        json_result(&results)
    }

    #[tool(
        description = "List or search all registered Tauri commands with their argument schemas. Pass query to filter by name/description substring. Commands are registered via #[inspectable] macro.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn get_registry(&self, Parameters(params): Parameters<RegistryParams>) -> CallToolResult {
        self.track_tool_call();
        let commands = match params.query {
            Some(q) => self.state.registry.search(&q),
            None => self.state.registry.list(),
        };
        json_result(&commands)
    }

    #[tool(
        description = "Get real-time process memory statistics from the OS (working set, page file usage). On Windows returns detailed metrics; on Linux returns virtual/resident size.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn get_memory_stats(&self) -> CallToolResult {
        self.track_tool_call();
        let stats = crate::memory::current_stats();
        json_result(&stats)
    }

    #[tool(
        description = "Inspect the Victauri plugin's own configuration: port, enabled/disabled tools, command filters, privacy settings, capacities, and version. Useful for agents to understand their capabilities before acting.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn get_plugin_info(&self) -> CallToolResult {
        self.track_tool_call();
        let disabled: Vec<&str> = self
            .state
            .privacy
            .disabled_tools
            .iter()
            .map(std::string::String::as_str)
            .collect();
        let blocklist: Vec<&str> = self
            .state
            .privacy
            .command_blocklist
            .iter()
            .map(std::string::String::as_str)
            .collect();
        let allowlist: Option<Vec<&str>> = self
            .state
            .privacy
            .command_allowlist
            .as_ref()
            .map(|s| s.iter().map(std::string::String::as_str).collect());
        let all_tools = Self::tool_router().list_all();
        let enabled_tools: Vec<&str> = all_tools
            .iter()
            .filter(|t| self.state.privacy.is_tool_enabled(t.name.as_ref()))
            .map(|t| t.name.as_ref())
            .collect();

        let result = serde_json::json!({
            "version": env!("CARGO_PKG_VERSION"),
            "bridge_version": BRIDGE_VERSION,
            "port": self.state.port.load(Ordering::Relaxed),
            "tools": {
                "total": all_tools.len(),
                "enabled": enabled_tools.len(),
                "enabled_list": enabled_tools,
                "disabled_list": disabled,
            },
            "commands": {
                "allowlist": allowlist,
                "blocklist": blocklist,
            },
            "privacy": {
                "profile": self.state.privacy.profile.to_string(),
                "redaction_enabled": self.state.privacy.redaction_enabled,
            },
            "capacities": {
                "event_log": self.state.event_log.capacity(),
                "eval_timeout_secs": self.state.eval_timeout.as_secs(),
            },
            "registered_commands": self.state.registry.count(),
            "tool_invocations": self.state.tool_invocations.load(std::sync::atomic::Ordering::Relaxed),
            "uptime_secs": self.state.started_at.elapsed().as_secs(),
        });
        json_result(&result)
    }

    #[tool(
        description = "Run environment diagnostics: detect service workers (break IPC interception), closed shadow DOM (invisible to snapshots), iframes (bridge absent), large DOM warnings, and CSP status. Call this first when connecting to an unfamiliar app.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn get_diagnostics(
        &self,
        Parameters(params): Parameters<DiagnosticsParams>,
    ) -> CallToolResult {
        self.eval_bridge(
            "return window.__VICTAURI__?.getDiagnostics()",
            params.webview_label.as_deref(),
        )
        .await
    }

    // ── Backend Access Tools ───────────────────────────────────────────────

    #[tool(
        description = "Get comprehensive app info: Tauri config (identifier, product name, version), app directory paths (data, config, log, local_data), process environment variables, and database files found in app directories. Provides direct backend context without going through the webview.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn app_info(&self) -> CallToolResult {
        self.track_tool_call();
        let config = self.bridge.tauri_config();

        let data_dir = self.bridge.app_data_dir().ok();
        let config_dir = self.bridge.app_config_dir().ok();
        let log_dir = self.bridge.app_log_dir().ok();
        let local_data_dir = self.bridge.app_local_data_dir().ok();

        let env_vars: std::collections::BTreeMap<String, String> = std::env::vars()
            .filter(|(k, _)| {
                let upper = k.to_uppercase();
                SAFE_ENV_PREFIXES
                    .iter()
                    .any(|prefix| upper.starts_with(prefix))
            })
            .collect();

        #[cfg(feature = "sqlite")]
        let databases: Vec<String> = data_dir
            .as_ref()
            .map(|d| {
                crate::database::discover_databases(d)
                    .into_iter()
                    .filter_map(|p| {
                        p.strip_prefix(d)
                            .ok()
                            .map(|rel| rel.to_string_lossy().into_owned())
                    })
                    .collect()
            })
            .unwrap_or_default();

        #[cfg(not(feature = "sqlite"))]
        let databases: Vec<String> = Vec::new();

        let result = serde_json::json!({
            "config": config,
            "paths": {
                "data": data_dir.as_ref().map(|p| p.to_string_lossy()),
                "config": config_dir.as_ref().map(|p| p.to_string_lossy()),
                "log": log_dir.as_ref().map(|p| p.to_string_lossy()),
                "local_data": local_data_dir.as_ref().map(|p| p.to_string_lossy()),
            },
            "databases": databases,
            "env": env_vars,
            "process": {
                "pid": std::process::id(),
                "arch": std::env::consts::ARCH,
                "os": std::env::consts::OS,
                "family": std::env::consts::FAMILY,
            },
        });
        json_result(&result)
    }

    #[tool(
        description = "List files in the app's data, config, log, or local_data directories. Useful for discovering databases, config files, logs, and cached data on the backend — without going through the webview.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn list_app_dir(
        &self,
        Parameters(params): Parameters<ListAppDirParams>,
    ) -> CallToolResult {
        self.track_tool_call();
        let base = match self.resolve_app_dir(params.directory) {
            Ok(d) => d,
            Err(e) => return tool_error(e),
        };

        let target = if let Some(ref sub) = params.path {
            let resolved = base.join(sub);
            if !resolved.exists() {
                return tool_error(format!("directory does not exist: {}", resolved.display()));
            }
            if let Err(e) = Self::safe_within(&base, &resolved) {
                return tool_error(e);
            }
            resolved
        } else {
            base.clone()
        };

        if !target.exists() {
            return tool_error(format!("directory does not exist: {}", target.display()));
        }

        let max_depth = params.max_depth.unwrap_or(1).min(5);
        let pattern = params.pattern.as_deref();
        let mut entries = Vec::new();

        Self::list_dir_recursive(&target, &base, 0, max_depth, pattern, &mut entries);

        json_result(&serde_json::json!({
            "base": base.to_string_lossy(),
            "path": params.path.unwrap_or_default(),
            "entries": entries,
            "count": entries.len(),
        }))
    }

    #[tool(
        description = "Read a file from the app's data, config, log, or local_data directory. Returns UTF-8 text by default, or base64 for binary files. Directly reads backend files without going through the webview.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn read_app_file(
        &self,
        Parameters(params): Parameters<ReadAppFileParams>,
    ) -> CallToolResult {
        self.track_tool_call();
        let base = match self.resolve_app_dir(params.directory) {
            Ok(d) => d,
            Err(e) => return tool_error(e),
        };

        let target = base.join(&params.path);
        if !target.exists() {
            return tool_error(format!("file not found: {}", params.path));
        }
        if let Err(e) = Self::safe_within(&base, &target) {
            return tool_error(e);
        }
        if !target.is_file() {
            return tool_error(format!("not a file: {}", params.path));
        }

        let max_bytes = params.max_bytes.unwrap_or(1_048_576).min(10_485_760);
        let metadata = std::fs::metadata(&target).map_err(|e| e.to_string());

        match std::fs::read(&target) {
            Ok(mut bytes) => {
                let original_size = bytes.len();
                let truncated = bytes.len() > max_bytes;
                if truncated {
                    bytes.truncate(max_bytes);
                }

                let file_info = serde_json::json!({
                    "path": params.path,
                    "size": original_size,
                    "truncated": truncated,
                    "modified": metadata.as_ref().ok()
                        .and_then(|m| m.modified().ok())
                        .map(|t| {
                            let duration = t.duration_since(std::time::SystemTime::UNIX_EPOCH).unwrap_or_default();
                            duration.as_secs()
                        }),
                });

                if params.binary == Some(true) {
                    use base64::Engine;
                    let b64 = base64::engine::general_purpose::STANDARD.encode(&bytes);
                    json_result(&serde_json::json!({
                        "file": file_info,
                        "encoding": "base64",
                        "content": b64,
                    }))
                } else {
                    match String::from_utf8(bytes) {
                        Ok(text) => json_result(&serde_json::json!({
                            "file": file_info,
                            "encoding": "utf-8",
                            "content": text,
                        })),
                        Err(e) => {
                            use base64::Engine;
                            let bytes = e.into_bytes();
                            let b64 = base64::engine::general_purpose::STANDARD.encode(&bytes);
                            json_result(&serde_json::json!({
                                "file": file_info,
                                "encoding": "base64",
                                "note": "file is not valid UTF-8, returning base64",
                                "content": b64,
                            }))
                        }
                    }
                }
            }
            Err(e) => tool_error(format!("failed to read file: {e}")),
        }
    }

    #[cfg(feature = "sqlite")]
    #[tool(
        description = "Execute a read-only SQL query against a SQLite database in the app's data directory. Auto-discovers database files if no path is specified. Only SELECT/PRAGMA/EXPLAIN/WITH queries are allowed. Returns rows as JSON objects with column names as keys. This provides direct backend database access without going through the webview or IPC.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn query_db(&self, Parameters(params): Parameters<QueryDbParams>) -> CallToolResult {
        self.track_tool_call();
        let data_dir = match self.bridge.app_data_dir() {
            Ok(d) => d,
            Err(e) => return tool_error(format!("cannot access app data directory: {e}")),
        };

        let app_dirs: Vec<std::path::PathBuf> = [
            self.bridge.app_data_dir(),
            self.bridge.app_config_dir(),
            self.bridge.app_local_data_dir(),
            self.bridge.app_log_dir(),
        ]
        .into_iter()
        .filter_map(Result::ok)
        .collect::<std::collections::HashSet<_>>()
        .into_iter()
        .collect();
        // Explicitly-configured roots (VictauriBuilder::db_search_paths) take
        // precedence over OS app directories for auto-discovery, so a configured
        // application DB wins over incidental ones (e.g. WebView internals).
        let mut search_dirs: Vec<std::path::PathBuf> = self.state.db_search_paths.clone();
        search_dirs.extend(app_dirs);

        let db_path = if let Some(ref rel_path) = params.path {
            let candidate = std::path::Path::new(rel_path);
            // Absolute paths are permitted only when they resolve within one of
            // the allowed roots (app directories or configured db_search_paths).
            if candidate.is_absolute() {
                if !candidate.exists() {
                    return tool_error(format!("database not found: {rel_path}"));
                }
                if !search_dirs
                    .iter()
                    .any(|d| Self::safe_within(d, candidate).is_ok())
                {
                    return tool_error(format!(
                        "absolute path '{rel_path}' is not within an allowed directory; \
                         register its parent via VictauriBuilder::db_search_paths"
                    ));
                }
            }
            let mut found = None;
            if candidate.is_absolute() {
                found = Some(candidate.to_path_buf());
            } else {
                for dir in &search_dirs {
                    let resolved = dir.join(rel_path);
                    if resolved.exists() {
                        if let Err(e) = Self::safe_within(dir, &resolved) {
                            return tool_error(e);
                        }
                        found = Some(resolved);
                        break;
                    }
                }
            }
            if let Some(p) = found {
                p
            } else {
                let dirs_str = search_dirs
                    .iter()
                    .map(|d| d.display().to_string())
                    .collect::<Vec<_>>()
                    .join(", ");
                return tool_error(format!(
                    "database not found: {rel_path} (searched: {dirs_str})"
                ));
            }
        } else {
            let mut databases = Vec::new();
            for dir in &search_dirs {
                databases.extend(crate::database::discover_databases(dir));
            }
            if let Some(p) = databases.first() {
                p.clone()
            } else {
                let dirs_str = search_dirs
                    .iter()
                    .map(|d| d.display().to_string())
                    .collect::<Vec<_>>()
                    .join(", ");
                return tool_error(format!("no SQLite databases found in: {dirs_str}"));
            }
        };

        let db_display = db_path
            .strip_prefix(&data_dir)
            .unwrap_or(&db_path)
            .to_string_lossy()
            .into_owned();
        let bind_params = params.params.unwrap_or_default();

        match crate::database::query(&db_path, &params.query, &bind_params, params.max_rows) {
            Ok(mut result) => {
                if let Some(obj) = result.as_object_mut() {
                    obj.insert("database".to_string(), serde_json::json!(db_display));
                }
                json_result(&result)
            }
            Err(e) => tool_error(e),
        }
    }

    // ── Compound Tools ──────────────────────────────────────────────────────

    #[tool(
        description = "DOM element interactions. Actions: click, double_click, hover, focus, scroll_into_view, select_option. Requires ref_id from a dom_snapshot for most actions.",
        annotations(
            read_only_hint = false,
            destructive_hint = false,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn interact(&self, Parameters(params): Parameters<InteractParams>) -> CallToolResult {
        if !self.state.privacy.is_tool_enabled("interact") {
            return tool_disabled("interact");
        }
        match params.action {
            InteractAction::Click => {
                if !self.state.privacy.is_tool_enabled("interact.click") {
                    return tool_disabled("interact.click");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "click");
                };
                let code = format!("return window.__VICTAURI__?.click({})", js_string(ref_id));
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InteractAction::DoubleClick => {
                if !self.state.privacy.is_tool_enabled("interact.double_click") {
                    return tool_disabled("interact.double_click");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "double_click");
                };
                let code = format!(
                    "return window.__VICTAURI__?.doubleClick({})",
                    js_string(ref_id)
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InteractAction::Hover => {
                if !self.state.privacy.is_tool_enabled("interact.hover") {
                    return tool_disabled("interact.hover");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "hover");
                };
                let code = format!("return window.__VICTAURI__?.hover({})", js_string(ref_id));
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InteractAction::Focus => {
                if !self.state.privacy.is_tool_enabled("interact.focus") {
                    return tool_disabled("interact.focus");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "focus");
                };
                let code = format!(
                    "return window.__VICTAURI__?.focusElement({})",
                    js_string(ref_id)
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InteractAction::ScrollIntoView => {
                if !self
                    .state
                    .privacy
                    .is_tool_enabled("interact.scroll_into_view")
                {
                    return tool_disabled("interact.scroll_into_view");
                }
                let ref_arg = params
                    .ref_id
                    .as_ref()
                    .map_or_else(|| "null".to_string(), |r| js_string(r));
                let x = params.x.unwrap_or(0.0);
                let y = params.y.unwrap_or(0.0);
                let code = format!("return window.__VICTAURI__?.scrollTo({ref_arg}, {x}, {y})");
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InteractAction::SelectOption => {
                if !self.state.privacy.is_tool_enabled("interact.select_option") {
                    return tool_disabled("interact.select_option");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "select_option");
                };
                let values_vec;
                let values: &[String] = match (&params.values, &params.value) {
                    (Some(v), _) => v,
                    (None, Some(v)) => {
                        values_vec = vec![v.clone()];
                        &values_vec
                    }
                    (None, None) => &[],
                };
                let values_json =
                    serde_json::to_string(values).unwrap_or_else(|_| "[]".to_string());
                let code = format!(
                    "return window.__VICTAURI__?.selectOption({}, {})",
                    js_string(ref_id),
                    values_json
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
        }
    }

    #[tool(
        description = "Text and keyboard input. Actions: fill (set input value), type_text (character-by-character typing), press_key (trigger a keyboard key). Subject to privacy controls.",
        annotations(
            read_only_hint = false,
            destructive_hint = false,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn input(&self, Parameters(params): Parameters<InputParams>) -> CallToolResult {
        match params.action {
            InputAction::Fill => {
                if !self.state.privacy.is_tool_enabled("fill") {
                    return tool_disabled("fill");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "fill");
                };
                let Some(value) = &params.value else {
                    return missing_param("value", "fill");
                };
                let code = format!(
                    "return window.__VICTAURI__?.fill({}, {})",
                    js_string(ref_id),
                    js_string(value)
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InputAction::TypeText => {
                if !self.state.privacy.is_tool_enabled("type_text") {
                    return tool_disabled("type_text");
                }
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "type_text");
                };
                let Some(text) = &params.text else {
                    return missing_param("text", "type_text");
                };
                let code = format!(
                    "return window.__VICTAURI__?.type({}, {})",
                    js_string(ref_id),
                    js_string(text)
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InputAction::PressKey => {
                if !self.state.privacy.is_tool_enabled("input.press_key") {
                    return tool_disabled("input.press_key");
                }
                let Some(key) = &params.key else {
                    return missing_param("key", "press_key");
                };
                let code = format!("return window.__VICTAURI__?.pressKey({})", js_string(key));
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
        }
    }

    #[tool(
        description = "Window management. Actions: get_state (window positions/sizes/visibility), list (all window labels), manage (minimize/maximize/close/focus/show/hide/fullscreen/always_on_top), resize, move_to, set_title.",
        annotations(
            read_only_hint = false,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn window(&self, Parameters(params): Parameters<WindowParams>) -> CallToolResult {
        self.track_tool_call();
        match params.action {
            WindowAction::GetState => {
                let states = self.bridge.get_window_states(params.label.as_deref());
                // A specific label that matches no window is an error, not an
                // empty array (which reads as "success, no state").
                if states.is_empty()
                    && let Some(label) = params.label.as_deref()
                {
                    return tool_error(format!(
                        "window not found: '{label}' (use window.list to see available labels)"
                    ));
                }
                json_result(&states)
            }
            WindowAction::List => {
                let labels = self.bridge.list_window_labels();
                json_result(&labels)
            }
            WindowAction::Manage => {
                if !self.state.privacy.is_tool_enabled("window.manage") {
                    return tool_disabled("window.manage");
                }
                let Some(manage_action) = &params.manage_action else {
                    return missing_param("manage_action", "manage");
                };
                match self
                    .bridge
                    .manage_window(params.label.as_deref(), manage_action.as_str())
                {
                    Ok(msg) => CallToolResult::success(vec![Content::text(msg)]),
                    Err(e) => tool_error(e),
                }
            }
            WindowAction::Resize => {
                if !self.state.privacy.is_tool_enabled("window.resize") {
                    return tool_disabled("window.resize");
                }
                let Some(width) = params.width else {
                    return missing_param("width", "resize");
                };
                let Some(height) = params.height else {
                    return missing_param("height", "resize");
                };
                if width == 0 || height == 0 {
                    return tool_error_with_hint(
                        format!(
                            "invalid window size {width}x{height}: width and height must be > 0"
                        ),
                        RecoveryHint::CheckInput,
                    );
                }
                match self
                    .bridge
                    .resize_window(params.label.as_deref(), width, height)
                {
                    Ok(()) => {
                        let result =
                            serde_json::json!({"ok": true, "width": width, "height": height});
                        CallToolResult::success(vec![Content::text(result.to_string())])
                    }
                    Err(e) => tool_error(e),
                }
            }
            WindowAction::MoveTo => {
                if !self.state.privacy.is_tool_enabled("window.move_to") {
                    return tool_disabled("window.move_to");
                }
                let Some(x) = params.x else {
                    return missing_param("x", "move_to");
                };
                let Some(y) = params.y else {
                    return missing_param("y", "move_to");
                };
                match self.bridge.move_window(params.label.as_deref(), x, y) {
                    Ok(()) => {
                        let result = serde_json::json!({"ok": true, "x": x, "y": y});
                        CallToolResult::success(vec![Content::text(result.to_string())])
                    }
                    Err(e) => tool_error(e),
                }
            }
            WindowAction::SetTitle => {
                if !self.state.privacy.is_tool_enabled("window.set_title") {
                    return tool_disabled("window.set_title");
                }
                let Some(title) = &params.title else {
                    return missing_param("title", "set_title");
                };
                match self.bridge.set_window_title(params.label.as_deref(), title) {
                    Ok(()) => {
                        let result = serde_json::json!({"ok": true, "title": title});
                        CallToolResult::success(vec![Content::text(result.to_string())])
                    }
                    Err(e) => tool_error(e),
                }
            }
        }
    }

    #[tool(
        description = "Browser storage operations. Actions: get (read localStorage/sessionStorage), set (write), delete (remove key), get_cookies. Subject to privacy controls for set and delete.",
        annotations(
            read_only_hint = false,
            destructive_hint = true,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn storage(&self, Parameters(params): Parameters<StorageParams>) -> CallToolResult {
        match params.action {
            StorageAction::Get => {
                let method = match params.storage_type.unwrap_or(StorageType::Local) {
                    StorageType::Session => "getSessionStorage",
                    StorageType::Local => "getLocalStorage",
                };
                let key_arg = params
                    .key
                    .as_ref()
                    .map(|k| js_string(k))
                    .unwrap_or_default();
                let code = format!("return window.__VICTAURI__?.{method}({key_arg})");
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            StorageAction::Set => {
                if !self.state.privacy.is_tool_enabled("set_storage") {
                    return tool_disabled("set_storage");
                }
                let method = match params.storage_type.unwrap_or(StorageType::Local) {
                    StorageType::Session => "setSessionStorage",
                    StorageType::Local => "setLocalStorage",
                };
                let Some(key) = &params.key else {
                    return missing_param("key", "set");
                };
                let value = params
                    .value
                    .as_ref()
                    .cloned()
                    .unwrap_or(serde_json::Value::Null);
                let value_json =
                    serde_json::to_string(&value).unwrap_or_else(|_| "null".to_string());
                let code = format!(
                    "return window.__VICTAURI__?.{method}({}, {value_json})",
                    js_string(key)
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            StorageAction::Delete => {
                if !self.state.privacy.is_tool_enabled("delete_storage") {
                    return tool_disabled("delete_storage");
                }
                let method = match params.storage_type.unwrap_or(StorageType::Local) {
                    StorageType::Session => "deleteSessionStorage",
                    StorageType::Local => "deleteLocalStorage",
                };
                let Some(key) = &params.key else {
                    return missing_param("key", "delete");
                };
                let code = format!("return window.__VICTAURI__?.{method}({})", js_string(key));
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            StorageAction::GetCookies => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.getCookies()",
                    params.webview_label.as_deref(),
                )
                .await
            }
        }
    }

    #[tool(
        description = "Navigation and dialog control. Actions: go_to (navigate to URL), go_back (browser back), get_history (navigation log), set_dialog_response (auto-respond to alert/confirm/prompt), get_dialog_log (captured dialog events). Subject to privacy controls for go_to and set_dialog_response.",
        annotations(
            read_only_hint = false,
            destructive_hint = false,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn navigate(&self, Parameters(params): Parameters<NavigateParams>) -> CallToolResult {
        match params.action {
            NavigateAction::GoTo => {
                if !self.state.privacy.is_tool_enabled("navigate") {
                    return tool_disabled("navigate");
                }
                let Some(url) = &params.url else {
                    return missing_param("url", "go_to");
                };
                if let Err(e) = validate_url(url, self.state.allow_file_navigation) {
                    return tool_error(e);
                }
                let code = format!("return window.__VICTAURI__?.navigate({})", js_string(url));
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            NavigateAction::GoBack => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.navigateBack()",
                    params.webview_label.as_deref(),
                )
                .await
            }
            NavigateAction::GetHistory => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.getNavigationLog()",
                    params.webview_label.as_deref(),
                )
                .await
            }
            NavigateAction::SetDialogResponse => {
                if !self.state.privacy.is_tool_enabled("set_dialog_response") {
                    return tool_disabled("set_dialog_response");
                }
                let Some(dialog_type) = params.dialog_type else {
                    return missing_param("dialog_type", "set_dialog_response");
                };
                let Some(dialog_action) = params.dialog_action else {
                    return missing_param("dialog_action", "set_dialog_response");
                };
                let text_arg = params
                    .text
                    .as_ref()
                    .map_or_else(|| "undefined".to_string(), |t| js_string(t));
                let code = format!(
                    "return window.__VICTAURI__?.setDialogAutoResponse({}, {}, {text_arg})",
                    js_string(dialog_type.as_str()),
                    js_string(dialog_action.as_str())
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            NavigateAction::GetDialogLog => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.getDialogLog()",
                    params.webview_label.as_deref(),
                )
                .await
            }
        }
    }

    #[tool(
        description = "Time-travel recording. Actions: start (begin recording), stop (end and return session), checkpoint (save state snapshot), list_checkpoints, get_events (since index), events_between (two checkpoints), get_replay (IPC replay sequence), export (session as JSON), import (load session from JSON), replay (re-execute recorded IPC commands and compare responses), flush (immediately drain pending events into recording without waiting for the 1-second poll).",
        annotations(
            read_only_hint = false,
            destructive_hint = false,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn recording(&self, Parameters(params): Parameters<RecordingParams>) -> CallToolResult {
        const MAX_SESSION_JSON: usize = 10 * 1024 * 1024;
        self.track_tool_call();
        if !self.state.privacy.is_tool_enabled("recording") {
            return tool_disabled("recording");
        }
        match params.action {
            RecordingAction::Start => {
                let session_id = params
                    .session_id
                    .unwrap_or_else(|| uuid::Uuid::new_v4().to_string());
                match self.state.recorder.start(session_id.clone()) {
                    Ok(()) => {
                        let result = serde_json::json!({
                            "started": true,
                            "session_id": session_id,
                        });
                        CallToolResult::success(vec![Content::text(result.to_string())])
                    }
                    Err(e) => tool_error(e.to_string()),
                }
            }
            RecordingAction::Stop => match self.state.recorder.stop() {
                Some(session) => json_result(&session),
                None => tool_error("no recording is active"),
            },
            RecordingAction::Checkpoint => {
                let Some(id) = params.checkpoint_id else {
                    return missing_param("checkpoint_id", "checkpoint");
                };
                let state = params.state.unwrap_or(serde_json::Value::Null);
                match self
                    .state
                    .recorder
                    .checkpoint(id.clone(), params.checkpoint_label, state)
                {
                    Ok(()) => {
                        let result = serde_json::json!({
                            "created": true,
                            "checkpoint_id": id,
                            "event_index": self.state.recorder.event_count(),
                        });
                        CallToolResult::success(vec![Content::text(result.to_string())])
                    }
                    Err(e) => tool_error(e.to_string()),
                }
            }
            RecordingAction::ListCheckpoints => {
                let checkpoints = self.state.recorder.get_checkpoints();
                json_result(&checkpoints)
            }
            RecordingAction::GetEvents => {
                let events = self
                    .state
                    .recorder
                    .events_since(params.since_index.unwrap_or(0));
                json_result(&events)
            }
            RecordingAction::EventsBetween => {
                let Some(from) = &params.from else {
                    return missing_param("from", "events_between");
                };
                let Some(to) = &params.to else {
                    return missing_param("to", "events_between");
                };
                match self.state.recorder.events_between_checkpoints(from, to) {
                    Ok(events) => json_result(&events),
                    Err(e) => tool_error(e.to_string()),
                }
            }
            RecordingAction::GetReplay => {
                let calls = self.state.recorder.ipc_replay_sequence();
                json_result(&calls)
            }
            RecordingAction::Export => match self.state.recorder.export() {
                Some(s) => {
                    let json = serde_json::to_string_pretty(&s)
                        .unwrap_or_else(|e| format!("{{\"error\": \"{e}\"}}"));
                    CallToolResult::success(vec![Content::text(json)])
                }
                None => tool_error("no recording is active — start one first"),
            },
            RecordingAction::Import => {
                let Some(session_json) = &params.session_json else {
                    return missing_param("session_json", "import");
                };
                if session_json.len() > MAX_SESSION_JSON {
                    return tool_error("session JSON exceeds maximum size (10 MB)");
                }
                let session: victauri_core::RecordedSession =
                    match serde_json::from_str(session_json) {
                        Ok(s) => s,
                        Err(e) => return tool_error(format!("invalid session JSON: {e}")),
                    };

                let result = serde_json::json!({
                    "imported": true,
                    "session_id": session.id,
                    "event_count": session.events.len(),
                    "checkpoint_count": session.checkpoints.len(),
                    "started_at": session.started_at.to_rfc3339(),
                });
                self.state.recorder.import(session);
                CallToolResult::success(vec![Content::text(result.to_string())])
            }
            RecordingAction::Flush => {
                if !self.state.recorder.is_recording() {
                    return tool_error("no active recording — start a recording first");
                }
                let code = "return window.__VICTAURI__?.getEventStream(0)";
                match self
                    .eval_with_return(code, params.webview_label.as_deref())
                    .await
                {
                    Ok(result_str) => {
                        let events: Vec<serde_json::Value> =
                            serde_json::from_str(&result_str).unwrap_or_default();
                        let mut count = 0u64;
                        for ev in &events {
                            if let Some(app_event) = crate::mcp::server::parse_bridge_event(ev) {
                                self.state.event_log.push(app_event.clone());
                                self.state.recorder.record_event(app_event);
                                count += 1;
                            }
                        }
                        json_result(&serde_json::json!({
                            "flushed": true,
                            "events_captured": count,
                        }))
                    }
                    Err(e) => tool_error(format!("flush failed: {e}")),
                }
            }
            RecordingAction::Replay => {
                let calls = self.state.recorder.ipc_replay_sequence();
                if calls.is_empty() {
                    return tool_error("no IPC calls recorded — record a session first");
                }
                let mut replay_results = Vec::new();
                for call in &calls {
                    let code = format!(
                        "return window.__TAURI_INTERNALS__.invoke({})",
                        js_string(&call.command)
                    );
                    let outcome = match self
                        .eval_with_return(&code, params.webview_label.as_deref())
                        .await
                    {
                        Ok(result_str) => {
                            let value: serde_json::Value = serde_json::from_str(&result_str)
                                .unwrap_or(serde_json::Value::String(result_str));
                            let shape = crate::introspection::JsonShape::from_value(&value);
                            serde_json::json!({
                                "command": call.command,
                                "status": "ok",
                                "response_type": shape.type_name(),
                            })
                        }
                        Err(e) => {
                            serde_json::json!({
                                "command": call.command,
                                "status": "error",
                                "error": e,
                            })
                        }
                    };
                    replay_results.push(outcome);
                }
                let passed = replay_results
                    .iter()
                    .filter(|r| r.get("status").and_then(|s| s.as_str()) == Some("ok"))
                    .count();
                let result = serde_json::json!({
                    "replayed": replay_results.len(),
                    "passed": passed,
                    "failed": replay_results.len() - passed,
                    "results": replay_results,
                });
                json_result(&result)
            }
        }
    }

    #[tool(
        description = "CSS and visual inspection. Actions: get_styles (computed CSS for element), get_bounding_boxes (layout rects), highlight (debug overlay), clear_highlights, audit_accessibility (a11y audit), get_performance (timing/heap/DOM metrics).",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn inspect(&self, Parameters(params): Parameters<InspectParams>) -> CallToolResult {
        match params.action {
            InspectAction::GetStyles => {
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "get_styles");
                };
                let props_arg = match &params.properties {
                    Some(props) => {
                        let arr: Vec<String> = props.iter().map(|p| js_string(p)).collect();
                        format!("[{}]", arr.join(","))
                    }
                    None => "null".to_string(),
                };
                let code = format!(
                    "return window.__VICTAURI__?.getStyles({}, {})",
                    js_string(ref_id),
                    props_arg
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InspectAction::GetBoundingBoxes => {
                let Some(ref_ids) = &params.ref_ids else {
                    return missing_param("ref_ids", "get_bounding_boxes");
                };
                let refs: Vec<String> = ref_ids.iter().map(|r| js_string(r)).collect();
                let code = format!(
                    "return window.__VICTAURI__?.getBoundingBoxes([{}])",
                    refs.join(",")
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InspectAction::Highlight => {
                let Some(ref_id) = &params.ref_id else {
                    return missing_param("ref_id", "highlight");
                };
                let color_arg = match &params.color {
                    Some(c) => match sanitize_css_color(c) {
                        Ok(safe) => format!("\"{safe}\""),
                        Err(e) => return tool_error(e),
                    },
                    None => "null".to_string(),
                };
                let label_arg = match &params.label {
                    Some(l) => js_string(l),
                    None => "null".to_string(),
                };
                let code = format!(
                    "return window.__VICTAURI__?.highlightElement({}, {}, {})",
                    js_string(ref_id),
                    color_arg,
                    label_arg
                );
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            InspectAction::ClearHighlights => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.clearHighlights()",
                    params.webview_label.as_deref(),
                )
                .await
            }
            InspectAction::AuditAccessibility => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.auditAccessibility()",
                    params.webview_label.as_deref(),
                )
                .await
            }
            InspectAction::GetPerformance => {
                self.eval_bridge(
                    "return window.__VICTAURI__?.getPerformanceMetrics()",
                    params.webview_label.as_deref(),
                )
                .await
            }
        }
    }

    #[tool(
        description = "CSS injection. Actions: inject (add custom CSS to page), remove (remove previously injected CSS). Subject to privacy controls.",
        annotations(
            read_only_hint = false,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn css(&self, Parameters(params): Parameters<CssParams>) -> CallToolResult {
        match params.action {
            CssAction::Inject => {
                if !self.state.privacy.is_tool_enabled("inject_css") {
                    return tool_disabled("inject_css");
                }
                let Some(css) = &params.css else {
                    return missing_param("css", "inject");
                };
                let code = format!("return window.__VICTAURI__?.injectCss({})", js_string(css));
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            CssAction::Remove => {
                if !self.state.privacy.is_tool_enabled("css.remove") {
                    return tool_disabled("css.remove");
                }
                self.eval_bridge(
                    "return window.__VICTAURI__?.removeInjectedCss()",
                    params.webview_label.as_deref(),
                )
                .await
            }
        }
    }

    #[tool(
        description = "Application logs and monitoring. Actions: console (captured console.log/warn/error), network (intercepted fetch/XHR), ipc (IPC call log — set wait_for_capture=true to await response capture up to 500ms), navigation (URL change history), dialogs (alert/confirm/prompt events), events (combined event stream), slow_ipc (find slow IPC calls).",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn logs(&self, Parameters(params): Parameters<LogsParams>) -> CallToolResult {
        match params.action {
            LogsAction::Console => {
                let since_arg = params.since.map(|ts| format!("{ts}")).unwrap_or_default();
                let base = if since_arg.is_empty() {
                    "window.__VICTAURI__?.getConsoleLogs()".to_string()
                } else {
                    format!("window.__VICTAURI__?.getConsoleLogs({since_arg})")
                };
                let code = if let Some(limit) = params.limit {
                    format!("return ({base} || []).slice(-{limit})")
                } else {
                    format!("return {base}")
                };
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            LogsAction::Network => {
                let filter_arg = params
                    .filter
                    .as_ref()
                    .map_or_else(|| "null".to_string(), |f| js_string(f));
                let limit = params.limit.unwrap_or(DEFAULT_LOG_LIMIT);
                let source = format!("window.__VICTAURI__?.getNetworkLog({filter_arg}, {limit})");
                let code = trimmed_log_js(&source, limit);
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            LogsAction::Ipc => {
                let wait = params.wait_for_capture.unwrap_or(false);
                let limit = params.limit.unwrap_or(DEFAULT_LOG_LIMIT);
                if wait {
                    let inner = trimmed_log_js("window.__VICTAURI__.getIpcLog()", limit);
                    let code = format!(
                        r"return (async function() {{
                            await window.__VICTAURI__.waitForIpcComplete(500);
                            return (function() {{ {inner} }})();
                        }})()"
                    );
                    let timeout = std::time::Duration::from_millis(5000);
                    match self
                        .eval_with_return_timeout(&code, params.webview_label.as_deref(), timeout)
                        .await
                    {
                        Ok(result) => CallToolResult::success(vec![Content::text(result)]),
                        Err(e) => tool_error(e),
                    }
                } else {
                    let code = trimmed_log_js("window.__VICTAURI__?.getIpcLog()", limit);
                    self.eval_bridge(&code, params.webview_label.as_deref())
                        .await
                }
            }
            LogsAction::Navigation => {
                let code = if let Some(limit) = params.limit {
                    format!(
                        "return (window.__VICTAURI__?.getNavigationLog() || []).slice(-{limit})"
                    )
                } else {
                    "return window.__VICTAURI__?.getNavigationLog()".to_string()
                };
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            LogsAction::Dialogs => {
                let code = if let Some(limit) = params.limit {
                    format!("return (window.__VICTAURI__?.getDialogLog() || []).slice(-{limit})")
                } else {
                    "return window.__VICTAURI__?.getDialogLog()".to_string()
                };
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            LogsAction::Events => {
                let since_arg = params.since.map(|ts| format!("{ts}")).unwrap_or_default();
                let base = if since_arg.is_empty() {
                    "window.__VICTAURI__?.getEventStream()".to_string()
                } else {
                    format!("window.__VICTAURI__?.getEventStream({since_arg})")
                };
                let code = if let Some(limit) = params.limit {
                    format!("return ({base} || []).slice(-{limit})")
                } else {
                    format!("return {base}")
                };
                self.eval_bridge(&code, params.webview_label.as_deref())
                    .await
            }
            LogsAction::SlowIpc => {
                let Some(threshold) = params.threshold_ms else {
                    return missing_param("threshold_ms", "slow_ipc");
                };
                let limit = params.limit.unwrap_or(20);
                let mb = MAX_LOG_FIELD_BYTES;
                let code = format!(
                    r"return (function() {{
                        var MB = {mb};
                        function trimField(v) {{
                            if (typeof v === 'string') return v.length > MB ? (v.slice(0, MB) + '…[+' + (v.length - MB) + ' bytes truncated]') : v;
                            if (v && typeof v === 'object') {{ var s; try {{ s = JSON.stringify(v); }} catch (e) {{ s = ''; }} if (s.length > MB) return '[truncated ' + s.length + ' bytes]'; }}
                            return v;
                        }}
                        function trimEntry(e) {{ if (e == null || typeof e !== 'object') return e; var o = {{}}; for (var k in e) {{ if (Object.prototype.hasOwnProperty.call(e, k)) o[k] = trimField(e[k]); }} return o; }}
                        var log = window.__VICTAURI__?.getIpcLog() || [];
                        var slow = log.filter(function(c) {{ return (c.duration_ms || 0) > {threshold}; }});
                        slow.sort(function(a, b) {{ return (b.duration_ms || 0) - (a.duration_ms || 0); }});
                        return {{ threshold_ms: {threshold}, count: Math.min(slow.length, {limit}), calls: slow.slice(0, {limit}).map(trimEntry) }};
                    }})()",
                );
                self.eval_bridge(&code, None).await
            }
        }
    }

    // ── Backend Introspection ────────────────────────────────────────────────

    #[tool(
        description = "Deep backend introspection — command profiling, IPC contract testing, \
            coverage, startup timing, capability auditing, database diagnostics, process \
            enumeration, and event bus monitoring. \
            These features exploit Victauri's position inside the Rust process.\n\n\
            Actions:\n\
            - `command_timings`: Per-command execution timing stats (min/max/avg/p95). Set `slow_threshold_ms` to filter.\n\
            - `coverage`: Which registered commands have been called during this session.\n\
            - `contract_record`: Record a command's response shape as a baseline (requires `command`).\n\
            - `contract_check`: Check all recorded contracts for schema drift.\n\
            - `contract_list`: List all recorded contract baselines.\n\
            - `contract_clear`: Clear all recorded contract baselines.\n\
            - `startup_timing`: Victauri plugin initialization phase-by-phase timing breakdown.\n\
            - `capabilities`: Enumerate Tauri v2 capabilities, security config (CSP, freeze_prototype), configured plugins, and window definitions.\n\
            - `db_health`: SQLite database diagnostics (journal mode, WAL, page stats).\n\
            - `plugin_state`: Snapshot of the Victauri plugin's internal state (event log, registry, faults, recording, timings, etc.).\n\
            - `processes`: Enumerate the host process and all child processes (sidecars, background workers) with PID, name, and memory usage.\n\
            - `plugin_tasks`: List Victauri's own spawned async tasks (MCP server, event drain) with status.\n\
            - `event_bus`: List all captured Tauri events (automatically intercepted via listen_any — no app opt-in needed).\n\
            - `event_bus_clear`: Clear the event bus capture buffer.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn introspect(&self, Parameters(params): Parameters<IntrospectParams>) -> CallToolResult {
        self.track_tool_call();
        if !self.state.privacy.is_tool_enabled("introspect") {
            return tool_disabled("introspect");
        }

        match params.action {
            IntrospectAction::CommandTimings => {
                let mut stats = self.state.command_timings.all_stats();
                if let Some(threshold) = params.slow_threshold_ms {
                    stats.retain(|s| s.avg_ms >= threshold);
                }
                let result = serde_json::json!({
                    "commands": stats,
                    "total_commands_profiled": self.state.command_timings.all_stats().len(),
                    "slow_threshold_ms": params.slow_threshold_ms,
                });
                json_result(&result)
            }
            IntrospectAction::Coverage => {
                let registered: Vec<String> = self
                    .state
                    .registry
                    .list()
                    .iter()
                    .map(|c| c.name.clone())
                    .collect();

                let code = "return window.__VICTAURI__?.getIpcLog()";
                let invoked: std::collections::HashSet<String> = match self
                    .eval_with_return(code, params.webview_label.as_deref())
                    .await
                {
                    Ok(json_str) => {
                        if let Ok(entries) =
                            serde_json::from_str::<Vec<serde_json::Value>>(&json_str)
                        {
                            entries
                                .iter()
                                .filter_map(|e| e.get("command").and_then(|c| c.as_str()))
                                .map(String::from)
                                .collect()
                        } else {
                            std::collections::HashSet::new()
                        }
                    }
                    Err(_) => std::collections::HashSet::new(),
                };

                let uncovered: Vec<&String> = registered
                    .iter()
                    .filter(|cmd| !invoked.contains(cmd.as_str()))
                    .collect();

                let coverage_pct = if registered.is_empty() {
                    100.0
                } else {
                    let covered = registered.len() - uncovered.len();
                    (covered as f64 / registered.len() as f64) * 100.0
                };

                let result = serde_json::json!({
                    "registered_commands": registered.len(),
                    "invoked_commands": invoked.len(),
                    "coverage_pct": (coverage_pct * 10.0).round() / 10.0,
                    "uncovered": uncovered,
                    "invoked_not_registered": invoked.iter()
                        .filter(|cmd| !registered.contains(cmd))
                        .collect::<Vec<_>>(),
                });
                json_result(&result)
            }
            IntrospectAction::ContractRecord => {
                let Some(command) = params.command else {
                    return missing_param("command", "contract_record");
                };
                let args_json = params.args.unwrap_or(serde_json::json!({}));
                let args_str =
                    serde_json::to_string(&args_json).unwrap_or_else(|_| "{}".to_string());
                let code = format!(
                    "return window.__TAURI_INTERNALS__.invoke({}, {args_str})",
                    js_string(&command)
                );
                match self
                    .eval_with_return(&code, params.webview_label.as_deref())
                    .await
                {
                    Ok(result_str) => {
                        let value: serde_json::Value = serde_json::from_str(&result_str)
                            .unwrap_or(serde_json::Value::String(result_str.clone()));
                        let shape = crate::introspection::JsonShape::from_value(&value);
                        let sample = if result_str.len() > 4096 {
                            format!("{}...(truncated)", &result_str[..4096])
                        } else {
                            result_str
                        };
                        let baseline = crate::introspection::ContractBaseline {
                            command: command.clone(),
                            args: args_json,
                            shape: shape.clone(),
                            sample,
                            recorded_at: chrono_now(),
                        };
                        self.state.contract_store.record(baseline);
                        let result = serde_json::json!({
                            "recorded": true,
                            "command": command,
                            "shape_type": shape.type_name(),
                        });
                        json_result(&result)
                    }
                    Err(e) => tool_error(format!(
                        "failed to invoke '{command}' for contract recording: {e}"
                    )),
                }
            }
            IntrospectAction::ContractCheck => {
                let baselines = self.state.contract_store.all();
                if baselines.is_empty() {
                    return json_result(&serde_json::json!({
                        "checked": 0,
                        "message": "no contract baselines recorded — use contract_record first",
                    }));
                }
                let mut results = Vec::new();
                for baseline in &baselines {
                    let args_str =
                        serde_json::to_string(&baseline.args).unwrap_or_else(|_| "{}".to_string());
                    let code = format!(
                        "return window.__TAURI_INTERNALS__.invoke({}, {args_str})",
                        js_string(&baseline.command)
                    );
                    match self
                        .eval_with_return(&code, params.webview_label.as_deref())
                        .await
                    {
                        Ok(result_str) => {
                            let value: serde_json::Value = serde_json::from_str(&result_str)
                                .unwrap_or(serde_json::Value::String(result_str));
                            let current_shape = crate::introspection::JsonShape::from_value(&value);
                            let drift = crate::introspection::diff_shapes(
                                &baseline.shape,
                                &current_shape,
                                &baseline.command,
                            );
                            results.push(drift);
                        }
                        Err(e) => {
                            results.push(crate::introspection::ContractDrift {
                                command: baseline.command.clone(),
                                new_fields: Vec::new(),
                                removed_fields: Vec::new(),
                                type_changes: Vec::new(),
                                shape_matches: false,
                            });
                            tracing::warn!(
                                command = %baseline.command,
                                error = %e,
                                "contract check invocation failed"
                            );
                        }
                    }
                }
                let passing = results.iter().filter(|r| r.shape_matches).count();
                let result = serde_json::json!({
                    "checked": results.len(),
                    "passing": passing,
                    "failing": results.len() - passing,
                    "contracts": results,
                });
                json_result(&result)
            }
            IntrospectAction::ContractList => {
                let baselines = self.state.contract_store.all();
                let result = serde_json::json!({
                    "count": baselines.len(),
                    "baselines": baselines.iter().map(|b| serde_json::json!({
                        "command": b.command,
                        "shape_type": b.shape.type_name(),
                        "recorded_at": b.recorded_at,
                    })).collect::<Vec<_>>(),
                });
                json_result(&result)
            }
            IntrospectAction::ContractClear => {
                let cleared = self.state.contract_store.clear();
                json_result(&serde_json::json!({
                    "cleared": cleared,
                }))
            }
            IntrospectAction::StartupTiming => {
                let phases = self.state.startup_timeline.report();
                let result = serde_json::json!({
                    "phases": phases,
                    "total_ms": self.state.startup_timeline.total_ms(),
                    "uptime_secs": self.state.started_at.elapsed().as_secs(),
                });
                json_result(&result)
            }
            IntrospectAction::Capabilities => {
                let config = self.bridge.tauri_config();
                let live_windows = self.bridge.list_window_labels();

                let result = serde_json::json!({
                    "app": {
                        "identifier": config.get("identifier"),
                        "product_name": config.get("product_name"),
                        "version": config.get("version"),
                    },
                    "security": config.get("security"),
                    "configured_windows": config.get("windows"),
                    "live_windows": live_windows,
                    "configured_plugins": config.get("plugins"),
                    "victauri": {
                        "registered_commands": self.state.registry.list().len(),
                        "auth_enabled": self.state.privacy.redaction_enabled,
                        "privacy_profile": format!("{:?}", self.state.privacy.profile),
                        "disabled_tools": &self.state.privacy.disabled_tools,
                    },
                });
                json_result(&result)
            }
            #[allow(unused_variables)]
            IntrospectAction::DbHealth => {
                #[cfg(feature = "sqlite")]
                {
                    let db_path = params.db_path.clone();
                    match self.run_db_health(db_path.as_deref()).await {
                        Ok(health) => json_result(&health),
                        Err(e) => tool_error(format!("db_health failed: {e}")),
                    }
                }
                #[cfg(not(feature = "sqlite"))]
                {
                    tool_error("SQLite support not compiled in — enable the `sqlite` feature")
                }
            }
            IntrospectAction::PluginState => {
                let recording_active = self.state.recorder.is_recording();
                let recording_events = self.state.recorder.event_count();
                let result = serde_json::json!({
                    "event_log": {
                        "size": self.state.event_log.len(),
                        "capacity": self.state.event_log.capacity(),
                    },
                    "registry": {
                        "commands_registered": self.state.registry.list().len(),
                    },
                    "recording": {
                        "active": recording_active,
                        "events_captured": recording_events,
                    },
                    "faults": {
                        "active_rules": self.state.fault_registry.list().len(),
                    },
                    "contracts": {
                        "baselines_recorded": self.state.contract_store.all().len(),
                    },
                    "timings": {
                        "commands_profiled": self.state.command_timings.all_stats().len(),
                    },
                    "event_bus": {
                        "captured_events": self.state.event_bus.len(),
                    },
                    "tasks": {
                        "total": self.state.task_tracker.list().len(),
                        "active": self.state.task_tracker.active_count(),
                    },
                    "tool_invocations": self.state.tool_invocations.load(Ordering::Relaxed),
                    "uptime_secs": self.state.started_at.elapsed().as_secs(),
                    "port": self.state.port.load(std::sync::atomic::Ordering::Relaxed),
                });
                json_result(&result)
            }
            IntrospectAction::Processes => {
                let pid = std::process::id();
                let uptime = self.state.started_at.elapsed();
                let children = crate::introspection::enumerate_child_processes();
                let host_memory = crate::memory::current_stats();

                let result = serde_json::json!({
                    "host": {
                        "pid": pid,
                        "uptime_secs": uptime.as_secs(),
                        "platform": std::env::consts::OS,
                        "arch": std::env::consts::ARCH,
                        "memory": host_memory,
                    },
                    "children": children.iter().map(|c| serde_json::json!({
                        "pid": c.pid,
                        "name": c.name,
                        "memory_bytes": c.memory_bytes,
                    })).collect::<Vec<_>>(),
                    "child_count": children.len(),
                    "total_child_memory_bytes": children.iter().filter_map(|c| c.memory_bytes).sum::<u64>(),
                });
                json_result(&result)
            }
            IntrospectAction::PluginTasks => {
                let tasks = self.state.task_tracker.list();
                let active = self.state.task_tracker.active_count();
                let result = serde_json::json!({
                    "total": tasks.len(),
                    "active": active,
                    "finished": tasks.len() - active,
                    "tasks": tasks,
                });
                json_result(&result)
            }
            IntrospectAction::EventBus => {
                let tauri_events = self.state.event_bus.events();
                let app_events = self.state.event_log.snapshot();
                let result = serde_json::json!({
                    "tauri_events": {
                        "count": tauri_events.len(),
                        "events": tauri_events,
                    },
                    "app_events": {
                        "count": app_events.len(),
                        "capacity": self.state.event_log.capacity(),
                        "events": app_events,
                    },
                });
                json_result(&result)
            }
            IntrospectAction::EventBusClear => {
                let tauri_cleared = self.state.event_bus.clear();
                self.state.event_log.clear();
                json_result(&serde_json::json!({
                    "tauri_events_cleared": tauri_cleared,
                    "app_events_cleared": true,
                }))
            }
        }
    }

    // ── Fault Injection / Chaos Engineering ──────────────────────────────────

    #[tool(
        description = "Inject faults into Tauri IPC commands at the Rust layer for chaos engineering. \
            Simulate slow commands, backend errors, dropped responses, and corrupted data. \
            CDP cannot inject failures at the backend — it can only observe the frontend.\n\n\
            Actions:\n\
            - `inject`: Add a fault rule (requires `command`, `fault_type`). Optional: `delay_ms`, `error_message`, `max_triggers`.\n\
            - `list`: List all active fault injection rules.\n\
            - `clear`: Remove a specific fault rule (requires `command`).\n\
            - `clear_all`: Remove all fault rules.",
        annotations(
            read_only_hint = false,
            destructive_hint = true,
            idempotent_hint = false,
            open_world_hint = false
        )
    )]
    async fn fault(&self, Parameters(params): Parameters<FaultParams>) -> CallToolResult {
        self.track_tool_call();
        if !self.state.privacy.is_tool_enabled("fault") {
            return tool_disabled("fault");
        }

        match params.action {
            FaultAction::Inject => {
                let Some(command) = params.command else {
                    return missing_param("command", "inject");
                };
                let Some(fault_kind) = params.fault_type else {
                    return missing_param("fault_type", "inject");
                };
                let fault_type = match fault_kind {
                    FaultKind::Delay => {
                        let delay_ms = params.delay_ms.unwrap_or(1000);
                        crate::introspection::FaultType::Delay { delay_ms }
                    }
                    FaultKind::Error => {
                        let message = params
                            .error_message
                            .unwrap_or_else(|| "injected fault".to_string());
                        crate::introspection::FaultType::Error { message }
                    }
                    FaultKind::Drop => crate::introspection::FaultType::Drop,
                    FaultKind::Corrupt => crate::introspection::FaultType::Corrupt,
                };
                let config = crate::introspection::FaultConfig {
                    command: command.clone(),
                    fault_type: fault_type.clone(),
                    trigger_count: 0,
                    max_triggers: params.max_triggers.unwrap_or(0),
                    created_at: std::time::Instant::now(),
                };
                self.state.fault_registry.inject(config);
                let result = serde_json::json!({
                    "injected": true,
                    "command": command,
                    "fault_type": fault_type,
                    "max_triggers": params.max_triggers.unwrap_or(0),
                });
                json_result(&result)
            }
            FaultAction::List => {
                let faults = self.state.fault_registry.list();
                let result = serde_json::json!({
                    "count": faults.len(),
                    "faults": faults.iter().map(|f| serde_json::json!({
                        "command": f.command,
                        "fault_type": f.fault_type,
                        "trigger_count": f.trigger_count,
                        "max_triggers": f.max_triggers,
                    })).collect::<Vec<_>>(),
                });
                json_result(&result)
            }
            FaultAction::Clear => {
                let Some(command) = params.command else {
                    return missing_param("command", "clear");
                };
                let removed = self.state.fault_registry.clear(&command);
                json_result(&serde_json::json!({
                    "removed": removed,
                    "command": command,
                }))
            }
            FaultAction::ClearAll => {
                let removed = self.state.fault_registry.clear_all();
                json_result(&serde_json::json!({
                    "removed": removed,
                }))
            }
        }
    }

    // ── Cross-Layer Explanation ────────────────────────────────────────────

    #[tool(
        description = "Correlate recent activity across all layers into a coherent narrative. \
            CDP shows raw events per layer; Victauri correlates IPC + DOM + console + network \
            + window events across the Rust backend and webview simultaneously.\n\n\
            Actions:\n\
            - `summary`: High-level activity summary for the last N seconds (default 30). \
              Counts IPC calls, DOM mutations, console entries, network requests, errors.\n\
            - `last_action`: Correlate the most recent burst of events into a causal timeline \
              (e.g. 'IPC call → DOM update → console.log').\n\
            - `diff`: What changed in the last N seconds — event counts, errors, new IPC commands.",
        annotations(
            read_only_hint = true,
            destructive_hint = false,
            idempotent_hint = true,
            open_world_hint = false
        )
    )]
    async fn explain(&self, Parameters(params): Parameters<ExplainParams>) -> CallToolResult {
        self.track_tool_call();
        if !self.state.privacy.is_tool_enabled("explain") {
            return tool_disabled("explain");
        }

        match params.action {
            ExplainAction::Summary => {
                let secs = params.seconds.unwrap_or(30);
                let since = chrono::Utc::now()
                    - chrono::TimeDelta::try_seconds(secs as i64).unwrap_or_default();
                let events = self.state.event_log.since(since);

                let mut ipc_count = 0u64;
                let mut dom_mutations = 0u64;
                let mut state_changes = 0u64;
                let mut console_count = 0u64;
                let mut window_events = 0u64;
                let mut interactions = 0u64;
                let mut top_commands: HashMap<String, u64> = HashMap::new();
                let mut errors: Vec<String> = Vec::new();

                for event in &events {
                    match event {
                        victauri_core::AppEvent::Ipc(call) => {
                            ipc_count += 1;
                            *top_commands.entry(call.command.clone()).or_insert(0) += 1;
                            if let victauri_core::IpcResult::Err(e) = &call.result {
                                errors.push(format!("IPC {}: {e}", call.command));
                            }
                        }
                        victauri_core::AppEvent::DomMutation { mutation_count, .. } => {
                            dom_mutations += u64::from(*mutation_count)
                        }
                        victauri_core::AppEvent::StateChange { .. } => state_changes += 1,
                        victauri_core::AppEvent::Console { level, message, .. } => {
                            console_count += 1;
                            if level == "error" {
                                errors.push(format!("console.error: {message}"));
                            }
                        }
                        victauri_core::AppEvent::WindowEvent { .. } => window_events += 1,
                        victauri_core::AppEvent::DomInteraction { .. } => interactions += 1,
                        _ => {}
                    }
                }

                let mut sorted_cmds: Vec<_> = top_commands.into_iter().collect();
                sorted_cmds.sort_by_key(|b| std::cmp::Reverse(b.1));
                let top: Vec<_> = sorted_cmds.iter().take(5).collect();

                let narrative = format!(
                    "{ipc_count} IPC call{} in the last {secs}s{}. \
                     {dom_mutations} DOM mutation{}, {interactions} interaction{}, \
                     {console_count} console message{}, {window_events} window event{}. {}.",
                    if ipc_count == 1 { "" } else { "s" },
                    if top.is_empty() {
                        String::new()
                    } else {
                        format!(
                            ", dominated by {}",
                            top.iter()
                                .map(|(cmd, n)| format!("{cmd} ({n}x)"))
                                .collect::<Vec<_>>()
                                .join(", ")
                        )
                    },
                    if dom_mutations == 1 { "" } else { "s" },
                    if interactions == 1 { "" } else { "s" },
                    if console_count == 1 { "" } else { "s" },
                    if window_events == 1 { "" } else { "s" },
                    if errors.is_empty() {
                        "No errors".to_string()
                    } else {
                        format!(
                            "{} error{}",
                            errors.len(),
                            if errors.len() == 1 { "" } else { "s" }
                        )
                    },
                );

                let result = serde_json::json!({
                    "time_window_secs": secs,
                    "total_events": events.len(),
                    "ipc_calls": ipc_count,
                    "dom_mutations": dom_mutations,
                    "state_changes": state_changes,
                    "console_messages": console_count,
                    "window_events": window_events,
                    "interactions": interactions,
                    "top_commands": sorted_cmds.iter().take(5).map(|(cmd, n)| {
                        serde_json::json!({"command": cmd, "count": n})
                    }).collect::<Vec<_>>(),
                    "errors": errors,
                    "narrative": narrative,
                });
                json_result(&result)
            }
            ExplainAction::LastAction => {
                let secs = params.seconds.unwrap_or(5);
                let since = chrono::Utc::now()
                    - chrono::TimeDelta::try_seconds(secs as i64).unwrap_or_default();
                let events = self.state.event_log.since(since);

                let timeline: Vec<serde_json::Value> = events
                    .iter()
                    .filter(|e| !e.is_internal())
                    .map(|event| match event {
                        victauri_core::AppEvent::Ipc(call) => serde_json::json!({
                            "time": call.timestamp.to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "ipc",
                            "detail": format!(
                                "{} {} ({}ms)",
                                call.command,
                                call.result,
                                call.duration_ms.unwrap_or(0)
                            ),
                        }),
                        victauri_core::AppEvent::DomMutation {
                            timestamp,
                            mutation_count,
                            webview_label,
                        } => serde_json::json!({
                            "time": timestamp.to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "dom_mutation",
                            "detail": format!(
                                "{mutation_count} element{} updated in {webview_label}",
                                if *mutation_count == 1 { "" } else { "s" }
                            ),
                        }),
                        victauri_core::AppEvent::DomInteraction {
                            timestamp,
                            action,
                            selector,
                            ..
                        } => serde_json::json!({
                            "time": timestamp.to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "interaction",
                            "detail": format!("{action} on {selector}"),
                        }),
                        victauri_core::AppEvent::StateChange {
                            timestamp,
                            key,
                            caused_by,
                        } => serde_json::json!({
                            "time": timestamp.to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "state_change",
                            "detail": format!(
                                "{key} changed{}",
                                caused_by.as_ref().map_or(String::new(), |c| format!(" (by {c})"))
                            ),
                        }),
                        victauri_core::AppEvent::Console {
                            timestamp,
                            level,
                            message,
                        } => serde_json::json!({
                            "time": timestamp.to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "console",
                            "detail": format!("console.{level}: {message}"),
                        }),
                        victauri_core::AppEvent::WindowEvent {
                            timestamp,
                            label,
                            event,
                        } => serde_json::json!({
                            "time": timestamp.to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "window_event",
                            "detail": format!("{event} on window '{label}'"),
                        }),
                        _ => serde_json::json!({
                            "time": event.timestamp().to_rfc3339_opts(
                                chrono::SecondsFormat::Millis, true
                            ),
                            "type": "other",
                            "detail": "unknown event type",
                        }),
                    })
                    .collect();

                let narrative = if timeline.is_empty() {
                    format!("No activity in the last {secs}s.")
                } else {
                    let parts: Vec<String> = timeline
                        .iter()
                        .filter_map(|e| e.get("detail").and_then(|d| d.as_str()))
                        .map(String::from)
                        .collect();
                    parts.join(" → ")
                };

                let result = serde_json::json!({
                    "time_window_secs": secs,
                    "event_count": timeline.len(),
                    "timeline": timeline,
                    "narrative": narrative,
                });
                json_result(&result)
            }
            ExplainAction::Diff => {
                let secs = params.seconds.unwrap_or(10);
                let since = chrono::Utc::now()
                    - chrono::TimeDelta::try_seconds(secs as i64).unwrap_or_default();
                let events = self.state.event_log.since(since);

                let mut ipc_commands: Vec<String> = Vec::new();
                let mut dom_changes = 0u64;
                let mut error_count = 0u64;
                let mut interaction_count = 0u64;
                let mut console_messages = 0u64;

                for event in &events {
                    if event.is_internal() {
                        continue;
                    }
                    match event {
                        victauri_core::AppEvent::Ipc(call) => {
                            ipc_commands.push(call.command.clone());
                            if matches!(call.result, victauri_core::IpcResult::Err(_)) {
                                error_count += 1;
                            }
                        }
                        victauri_core::AppEvent::DomMutation { mutation_count, .. } => {
                            dom_changes += u64::from(*mutation_count)
                        }
                        victauri_core::AppEvent::DomInteraction { .. } => {
                            interaction_count += 1;
                        }
                        victauri_core::AppEvent::Console { level, .. } => {
                            console_messages += 1;
                            if level == "error" {
                                error_count += 1;
                            }
                        }
                        _ => {}
                    }
                }

                ipc_commands.dedup();

                let result = serde_json::json!({
                    "since": since.to_rfc3339_opts(chrono::SecondsFormat::Secs, true),
                    "time_window_secs": secs,
                    "total_events": events.len(),
                    "ipc_calls_made": ipc_commands.len(),
                    "unique_commands": ipc_commands,
                    "dom_elements_changed": dom_changes,
                    "interactions": interaction_count,
                    "console_messages": console_messages,
                    "errors": error_count,
                });
                json_result(&result)
            }
        }
    }
}

impl VictauriMcpHandler {
    /// Create a new handler backed by the given state and webview bridge.
    pub fn new(state: Arc<VictauriState>, bridge: Arc<dyn WebviewBridge>) -> Self {
        Self {
            state,
            bridge,
            subscriptions: Arc::new(Mutex::new(HashSet::new())),
            bridge_checked: Arc::new(AtomicBool::new(false)),
            probed_labels: Arc::new(Mutex::new(HashSet::new())),
        }
    }

    pub(crate) fn is_tool_enabled(&self, name: &str) -> bool {
        self.state.privacy.is_tool_enabled(name)
    }

    pub(crate) async fn execute_tool(
        &self,
        name: &str,
        args: serde_json::Value,
    ) -> Result<CallToolResult, rest::ToolCallError> {
        if !self.state.privacy.is_tool_enabled(name) {
            return Ok(tool_disabled(name));
        }
        self.state.tool_invocations.fetch_add(1, Ordering::Relaxed);
        let start = std::time::Instant::now();
        tracing::debug!(tool = %name, "REST tool invocation started");

        let result = match name {
            "eval_js" => {
                let p: EvalJsParams = Self::parse_args(args)?;
                self.eval_js(Parameters(p)).await
            }
            "dom_snapshot" => {
                let p: SnapshotParams = Self::parse_args(args)?;
                self.dom_snapshot(Parameters(p)).await
            }
            "find_elements" => {
                let p: FindElementsParams = Self::parse_args(args)?;
                self.find_elements(Parameters(p)).await
            }
            "invoke_command" => {
                let p: InvokeCommandParams = Self::parse_args(args)?;
                self.invoke_command(Parameters(p)).await
            }
            "screenshot" => {
                let p: ScreenshotParams = Self::parse_args(args)?;
                self.screenshot(Parameters(p)).await
            }
            "verify_state" => {
                let p: VerifyStateParams = Self::parse_args(args)?;
                self.verify_state(Parameters(p)).await
            }
            "detect_ghost_commands" => {
                let p: GhostCommandParams = Self::parse_args(args)?;
                self.detect_ghost_commands(Parameters(p)).await
            }
            "check_ipc_integrity" => {
                let p: IpcIntegrityParams = Self::parse_args(args)?;
                self.check_ipc_integrity(Parameters(p)).await
            }
            "wait_for" => {
                let p: WaitForParams = Self::parse_args(args)?;
                self.wait_for(Parameters(p)).await
            }
            "assert_semantic" => {
                let p: SemanticAssertParams = Self::parse_args(args)?;
                self.assert_semantic(Parameters(p)).await
            }
            "resolve_command" => {
                let p: ResolveCommandParams = Self::parse_args(args)?;
                self.resolve_command(Parameters(p)).await
            }
            "get_registry" => {
                let p: RegistryParams = Self::parse_args(args)?;
                self.get_registry(Parameters(p)).await
            }
            "get_memory_stats" => self.get_memory_stats().await,
            "get_plugin_info" => self.get_plugin_info().await,
            "get_diagnostics" => {
                let p: DiagnosticsParams = Self::parse_args(args)?;
                self.get_diagnostics(Parameters(p)).await
            }
            "app_info" => self.app_info().await,
            "list_app_dir" => {
                let p: ListAppDirParams = Self::parse_args(args)?;
                self.list_app_dir(Parameters(p)).await
            }
            "read_app_file" => {
                let p: ReadAppFileParams = Self::parse_args(args)?;
                self.read_app_file(Parameters(p)).await
            }
            #[cfg(feature = "sqlite")]
            "query_db" => {
                let p: QueryDbParams = Self::parse_args(args)?;
                self.query_db(Parameters(p)).await
            }
            "interact" => {
                let p: InteractParams = Self::parse_args(args)?;
                self.interact(Parameters(p)).await
            }
            "input" => {
                let p: InputParams = Self::parse_args(args)?;
                self.input(Parameters(p)).await
            }
            "window" => {
                let p: WindowParams = Self::parse_args(args)?;
                self.window(Parameters(p)).await
            }
            "storage" => {
                let p: StorageParams = Self::parse_args(args)?;
                self.storage(Parameters(p)).await
            }
            "navigate" => {
                let p: NavigateParams = Self::parse_args(args)?;
                self.navigate(Parameters(p)).await
            }
            "recording" => {
                let p: RecordingParams = Self::parse_args(args)?;
                self.recording(Parameters(p)).await
            }
            "inspect" => {
                let p: InspectParams = Self::parse_args(args)?;
                self.inspect(Parameters(p)).await
            }
            "css" => {
                let p: CssParams = Self::parse_args(args)?;
                self.css(Parameters(p)).await
            }
            "logs" => {
                let p: LogsParams = Self::parse_args(args)?;
                self.logs(Parameters(p)).await
            }
            "introspect" => {
                let p: IntrospectParams = Self::parse_args(args)?;
                self.introspect(Parameters(p)).await
            }
            "fault" => {
                let p: FaultParams = Self::parse_args(args)?;
                self.fault(Parameters(p)).await
            }
            "explain" => {
                let p: ExplainParams = Self::parse_args(args)?;
                self.explain(Parameters(p)).await
            }
            _ => return Err(rest::ToolCallError::UnknownTool(name.to_string())),
        };

        let elapsed = start.elapsed();
        tracing::debug!(
            tool = %name,
            elapsed_ms = elapsed.as_millis() as u64,
            "REST tool invocation completed"
        );

        if self.state.privacy.redaction_enabled {
            Ok(Self::redact_result(result, &self.state.privacy))
        } else {
            Ok(result)
        }
    }

    fn parse_args<T: serde::de::DeserializeOwned>(
        args: serde_json::Value,
    ) -> Result<T, rest::ToolCallError> {
        serde_json::from_value(args).map_err(|e| rest::ToolCallError::InvalidParams(e.to_string()))
    }

    fn redact_result(
        mut result: CallToolResult,
        privacy: &crate::privacy::PrivacyConfig,
    ) -> CallToolResult {
        for item in &mut result.content {
            if let RawContent::Text(ref mut tc) = item.raw {
                tc.text = privacy.redact_output(&tc.text);
            }
        }
        result
    }

    fn track_tool_call(&self) {
        self.state.tool_invocations.fetch_add(1, Ordering::Relaxed);
    }

    fn resolve_app_dir(&self, dir: Option<AppDir>) -> Result<std::path::PathBuf, String> {
        match dir.unwrap_or(AppDir::Data) {
            AppDir::Data => self.bridge.app_data_dir(),
            AppDir::Config => self.bridge.app_config_dir(),
            AppDir::Log => self.bridge.app_log_dir(),
            AppDir::LocalData => self.bridge.app_local_data_dir(),
        }
    }

    fn safe_within(base: &std::path::Path, target: &std::path::Path) -> Result<(), String> {
        let canon_base = std::fs::canonicalize(base)
            .map_err(|e| format!("cannot resolve base directory: {e}"))?;
        let canon_target = std::fs::canonicalize(target)
            .map_err(|e| format!("cannot resolve target path: {e}"))?;
        if !canon_target.starts_with(&canon_base) {
            return Err("path traversal not allowed".to_string());
        }
        Ok(())
    }

    fn list_dir_recursive(
        dir: &std::path::Path,
        base: &std::path::Path,
        depth: u32,
        max_depth: u32,
        pattern: Option<&str>,
        entries: &mut Vec<serde_json::Value>,
    ) {
        let Ok(read_dir) = std::fs::read_dir(dir) else {
            return;
        };
        for entry in read_dir.flatten() {
            let path = entry.path();
            if path.is_symlink() {
                continue;
            }
            let name = entry.file_name().to_string_lossy().into_owned();
            let relative = path
                .strip_prefix(base)
                .unwrap_or(&path)
                .to_string_lossy()
                .into_owned();

            if let Some(pat) = pattern
                && !Self::matches_glob(&name, pat)
                && !path.is_dir()
            {
                continue;
            }

            let is_dir = path.is_dir();
            let meta = std::fs::metadata(&path).ok();

            entries.push(serde_json::json!({
                "name": name,
                "path": relative,
                "is_dir": is_dir,
                "size": meta.as_ref().map(std::fs::Metadata::len),
                "modified": meta.as_ref()
                    .and_then(|m| m.modified().ok())
                    .map(|t| t.duration_since(std::time::SystemTime::UNIX_EPOCH)
                        .unwrap_or_default().as_secs()),
            }));

            if is_dir && depth < max_depth {
                Self::list_dir_recursive(&path, base, depth + 1, max_depth, pattern, entries);
            }
        }
    }

    fn matches_glob(name: &str, pattern: &str) -> bool {
        if pattern == "*" {
            return true;
        }
        if let Some(suffix) = pattern.strip_prefix("*.") {
            return name.ends_with(&format!(".{suffix}"));
        }
        if let Some(prefix) = pattern.strip_suffix("*") {
            return name.starts_with(prefix);
        }
        name == pattern
    }

    async fn eval_bridge(&self, code: &str, webview_label: Option<&str>) -> CallToolResult {
        match self.eval_with_return(code, webview_label).await {
            Ok(result) => CallToolResult::success(vec![Content::text(result)]),
            Err(e) => tool_error(e),
        }
    }

    async fn eval_with_return(
        &self,
        code: &str,
        webview_label: Option<&str>,
    ) -> Result<String, String> {
        self.eval_with_return_timeout(code, webview_label, self.state.eval_timeout)
            .await
    }

    async fn probe_bridge(&self, webview_label: Option<&str>) -> Result<(), String> {
        let id = uuid::Uuid::new_v4().to_string();
        let (tx, rx) = tokio::sync::oneshot::channel();
        {
            let mut pending = self.state.pending_evals.lock().await;
            pending.insert(id.clone(), tx);
        }
        let id_js = js_string(&id);
        let probe = format!(
            r#"(async()=>{{await window.__TAURI_INTERNALS__.invoke('plugin:victauri|victauri_eval_callback',{{id:{id_js},result:'"probe_ok"'}});}})();"#
        );
        if let Err(e) = self.bridge.eval_webview(webview_label, &probe) {
            self.state.pending_evals.lock().await.remove(&id);
            return Err(format!("eval injection failed: {e}"));
        }
        if let Ok(Ok(_)) = tokio::time::timeout(std::time::Duration::from_secs(2), rx).await {
            Ok(())
        } else {
            self.state.pending_evals.lock().await.remove(&id);
            let label = webview_label.unwrap_or("default");
            Err(format!(
                "bridge not responding on window '{label}' — the window may be hidden, \
                 missing the victauri capability, or the JS bridge is not loaded"
            ))
        }
    }

    async fn eval_with_return_timeout(
        &self,
        code: &str,
        webview_label: Option<&str>,
        timeout: std::time::Duration,
    ) -> Result<String, String> {
        self.track_tool_call();

        // Wait for the JS bridge ready signal (sent on bridge init) before
        // attempting evals.  For explicitly targeted windows the probe
        // mechanism is still used because the ready signal only proves that
        // *some* webview's bridge loaded — not necessarily the targeted one.
        if !self
            .state
            .bridge_ready
            .load(std::sync::atomic::Ordering::Acquire)
        {
            let notified = self.state.bridge_notify.notified();
            if !self
                .state
                .bridge_ready
                .load(std::sync::atomic::Ordering::Acquire)
            {
                let _ = tokio::time::timeout(std::time::Duration::from_secs(5), notified).await;
            }
        }

        if webview_label.is_some() {
            let label_key = webview_label.unwrap_or_default().to_string();
            let already_probed = self.probed_labels.lock().await.contains(&label_key);
            if !already_probed {
                self.probe_bridge(webview_label).await?;
                self.probed_labels.lock().await.insert(label_key);
            }
        }

        let id = uuid::Uuid::new_v4().to_string();
        let (tx, rx) = tokio::sync::oneshot::channel();

        {
            let mut pending = self.state.pending_evals.lock().await;
            if pending.len() >= MAX_PENDING_EVALS {
                return Err(format!(
                    "too many concurrent eval requests (limit: {MAX_PENDING_EVALS})"
                ));
            }
            pending.insert(id.clone(), tx);
        }

        // Auto-prepend `return` so bare expressions produce a value — but ONLY
        // for single expressions. Multi-statement blocks (or code containing an
        // explicit `return`) are used as-is. Prepending `return` to a statement
        // block like `foo(); return bar()` would parse as `return foo();` and
        // silently discard everything after the first statement (issue: core
        // primitive returned wrong/undefined values for "do X, then return Y").
        let code = if should_prepend_return(code) {
            format!("return {}", code.trim())
        } else {
            code.trim().to_string()
        };

        let id_js = js_string(&id);
        let inject = format!(
            r"
            (async () => {{
                try {{
                    const __result = await (async () => {{ {code} }})();
                    const __type = __result === undefined ? 'undefined'
                        : __result === null ? 'null' : 'value';
                    const __val = __type === 'undefined' ? null
                        : __type === 'null' ? null : __result;
                    await window.__TAURI_INTERNALS__.invoke('plugin:victauri|victauri_eval_callback', {{
                        id: {id_js},
                        result: JSON.stringify({{ __victauri_ok: __val, __victauri_type: __type }})
                    }});
                }} catch (e) {{
                    await window.__TAURI_INTERNALS__.invoke('plugin:victauri|victauri_eval_callback', {{
                        id: {id_js},
                        result: JSON.stringify({{ __victauri_err: String(e && e.message || e) }})
                    }});
                }}
            }})();
            "
        );

        if let Err(e) = self.bridge.eval_webview(webview_label, &inject) {
            self.state.pending_evals.lock().await.remove(&id);
            return Err(format!("eval injection failed: {e}"));
        }

        match tokio::time::timeout(timeout, rx).await {
            Ok(Ok(raw)) => {
                self.check_bridge_version_once();
                if raw.len() > MAX_EVAL_RESULT_LEN {
                    return Err(format!(
                        "eval result too large ({} bytes, limit {MAX_EVAL_RESULT_LEN})",
                        raw.len()
                    ));
                }
                unwrap_eval_envelope(raw)
            }
            Ok(Err(_)) => Err("eval callback channel closed".to_string()),
            Err(_) => {
                self.state.pending_evals.lock().await.remove(&id);
                Err(format!(
                    "eval timed out after {}s — the code never resolved. Common causes: a \
                     JavaScript syntax error in the injected code (parse errors cannot be \
                     reported by the webview and surface only as this timeout), an unresolved \
                     promise, or an infinite loop. Verify the code parses and resolves.",
                    timeout.as_secs()
                ))
            }
        }
    }

    #[cfg(feature = "sqlite")]
    async fn run_db_health(&self, db_path: Option<&str>) -> Result<serde_json::Value, String> {
        // Roots: configured db_search_paths first, then app directories.
        let mut roots: Vec<std::path::PathBuf> = self.state.db_search_paths.clone();
        for d in [
            self.bridge.app_data_dir(),
            self.bridge.app_local_data_dir(),
            self.bridge.app_config_dir(),
        ]
        .into_iter()
        .flatten()
        {
            roots.push(d);
        }

        let path = if let Some(p) = db_path {
            let candidate = std::path::Path::new(p);
            if candidate.is_absolute() {
                if !roots
                    .iter()
                    .any(|r| Self::safe_within(r, candidate).is_ok())
                {
                    return Err(format!(
                        "absolute path '{p}' is not within an allowed directory; \
                         register its parent via VictauriBuilder::db_search_paths"
                    ));
                }
                candidate.to_path_buf()
            } else {
                roots
                    .iter()
                    .map(|r| r.join(p))
                    .find(|c| c.exists())
                    .ok_or_else(|| format!("database not found: {p}"))?
            }
        } else {
            roots
                .iter()
                .flat_map(|r| crate::database::discover_databases(r))
                .next()
                .ok_or_else(|| {
                    "no database found in app directories or configured db_search_paths".to_string()
                })?
        };
        // No further containment check needed: the path is either discovered
        // within an allowed root, an existing relative file joined onto an
        // allowed root, or an absolute path already verified above. (A
        // safe_within check against app_data_dir would fail when that directory
        // does not exist — common for apps that store data elsewhere.)
        let path_str = path
            .to_str()
            .ok_or_else(|| "invalid path encoding".to_string())?
            .to_string();

        tokio::task::spawn_blocking(move || {
            let conn = rusqlite::Connection::open_with_flags(
                &path_str,
                rusqlite::OpenFlags::SQLITE_OPEN_READ_ONLY,
            )
            .map_err(|e| format!("cannot open database: {e}"))?;

            let journal_mode: String = conn
                .pragma_query_value(None, "journal_mode", |r| r.get(0))
                .unwrap_or_else(|_| "unknown".to_string());

            let page_count: i64 = conn
                .pragma_query_value(None, "page_count", |r| r.get(0))
                .unwrap_or(0);

            let page_size: i64 = conn
                .pragma_query_value(None, "page_size", |r| r.get(0))
                .unwrap_or(0);

            let freelist_count: i64 = conn
                .pragma_query_value(None, "freelist_count", |r| r.get(0))
                .unwrap_or(0);

            let wal_checkpoint: String = if journal_mode == "wal" {
                let mut info = String::from("n/a");
                let _ = conn.pragma_query(None, "wal_checkpoint", |r| {
                    let busy: i64 = r.get(0)?;
                    let checkpointed: i64 = r.get(1)?;
                    let total: i64 = r.get(2)?;
                    info = format!("busy={busy}, checkpointed={checkpointed}, total={total}");
                    Ok(())
                });
                info
            } else {
                "n/a (not WAL mode)".to_string()
            };

            let integrity: String = conn
                .pragma_query_value(None, "quick_check", |r| r.get(0))
                .unwrap_or_else(|_| "failed".to_string());

            let db_size_bytes = page_count * page_size;
            let db_size_mb = db_size_bytes as f64 / (1024.0 * 1024.0);

            let mut tables = Vec::new();
            if let Ok(mut stmt) =
                conn.prepare("SELECT name FROM sqlite_master WHERE type='table' ORDER BY name")
                && let Ok(rows) = stmt.query_map([], |r| r.get::<_, String>(0))
            {
                for name in rows.flatten() {
                    let count: i64 = conn
                        .query_row(&format!("SELECT count(*) FROM [{name}]"), [], |r| r.get(0))
                        .unwrap_or(0);
                    tables.push(serde_json::json!({
                        "name": name,
                        "row_count": count,
                    }));
                }
            }

            Ok(serde_json::json!({
                "database": path_str,
                "journal_mode": journal_mode,
                "page_count": page_count,
                "page_size": page_size,
                "db_size_mb": (db_size_mb * 100.0).round() / 100.0,
                "freelist_count": freelist_count,
                "wal_checkpoint": wal_checkpoint,
                "integrity_check": integrity,
                "tables": tables,
            }))
        })
        .await
        .map_err(|e| format!("db health task failed: {e}"))?
    }

    fn check_bridge_version_once(&self) {
        if self.bridge_checked.swap(true, Ordering::Relaxed) {
            return;
        }
        let handler = self.clone();
        tokio::spawn(async move {
            match handler
                .eval_with_return_timeout(
                    "window.__VICTAURI__?.version",
                    None,
                    std::time::Duration::from_secs(5),
                )
                .await
            {
                Ok(v) => {
                    let v = v.trim_matches('"');
                    if v == BRIDGE_VERSION {
                        tracing::debug!("Bridge version verified: {v}");
                    } else {
                        tracing::warn!(
                            "Bridge version mismatch: Rust expects {BRIDGE_VERSION}, JS reports {v}"
                        );
                    }
                }
                Err(e) => tracing::debug!("Bridge version check skipped: {e}"),
            }
        });
    }
}

const SERVER_INSTRUCTIONS: &str = "Victauri is a FULL-STACK inspection AND INTERVENTION tool for Tauri applications. \
It provides simultaneous access to three layers: (1) the WEBVIEW (DOM, interactions, JS eval), \
(2) the IPC LAYER (command registry, invoke commands, intercept traffic), and \
(3) the RUST BACKEND (app config, file system, SQLite databases, process memory). \
\n\nBACKEND tools (direct Rust access, no webview needed): \
'app_info' (app config, directory paths, discovered databases, process info), \
'list_app_dir' (browse app data/config/log directories), \
'read_app_file' (read files from app directories), \
'query_db' (read-only SQLite queries with auto-discovery). \
\n\nBACKEND INTROSPECTION (CDP cannot do this — Victauri-exclusive): \
'introspect' (command_timings, coverage, contract_record/check/list/clear, startup_timing, \
capabilities, db_health, plugin_state, processes, plugin_tasks, event_bus, event_bus_clear) — \
Rust-side performance profiling, IPC contract testing, command coverage analysis, startup timing, \
capability/security auditing, database diagnostics, plugin state, child process enumeration, \
task tracking, and automatic Tauri event bus monitoring. \
'fault' (inject, list, clear, clear_all) — chaos engineering: inject delays, errors, \
drops, and response corruption into Tauri commands at the Rust layer. \
'explain' (summary, last_action, diff) — cross-layer activity correlation: summarizes recent \
activity across IPC + DOM + console + network + window events into a coherent narrative. \
\n\nWEBVIEW tools: \
'interact' (click, hover, focus, scroll, select), 'input' (fill, type_text, press_key), \
'inspect' (get_styles, get_bounding_boxes, highlight, audit_accessibility, get_performance), \
'css' (inject, remove), eval_js, dom_snapshot, find_elements, screenshot. \
\n\nIPC tools: invoke_command, get_registry, detect_ghost_commands, check_ipc_integrity. \
\n\nCOMPOUND tools with an 'action' parameter: \
'window' (get_state, list, manage, resize, move_to, set_title), \
'storage' (get, set, delete, get_cookies), 'navigate' (go_to, go_back, get_history, \
set_dialog_response, get_dialog_log), 'recording' (start, stop, checkpoint, list_checkpoints, \
get_events, events_between, get_replay, export, import, replay), \
'logs' (console, network, ipc, navigation, dialogs, events, slow_ipc). \
\n\nOTHER: verify_state, wait_for, assert_semantic, resolve_command, \
get_memory_stats, get_plugin_info, get_diagnostics.";

impl ServerHandler for VictauriMcpHandler {
    fn get_info(&self) -> ServerInfo {
        ServerInfo::new(
            ServerCapabilities::builder()
                .enable_tools()
                .enable_resources()
                .enable_resources_subscribe()
                .build(),
        )
        .with_instructions(SERVER_INSTRUCTIONS)
    }

    async fn list_tools(
        &self,
        _request: Option<PaginatedRequestParams>,
        _context: RequestContext<RoleServer>,
    ) -> Result<ListToolsResult, ErrorData> {
        let all_tools = Self::tool_router().list_all();
        let filtered: Vec<Tool> = all_tools
            .into_iter()
            .filter(|t| self.state.privacy.is_tool_enabled(t.name.as_ref()))
            .collect();
        Ok(ListToolsResult {
            tools: filtered,
            ..Default::default()
        })
    }

    async fn call_tool(
        &self,
        request: CallToolRequestParams,
        context: RequestContext<RoleServer>,
    ) -> Result<CallToolResult, ErrorData> {
        let tool_name: String = request.name.as_ref().to_owned();
        if !self.state.privacy.is_tool_enabled(&tool_name) {
            tracing::debug!(tool = %tool_name, "tool call blocked by privacy config");
            return Ok(tool_disabled(&tool_name));
        }
        self.state
            .tool_invocations
            .fetch_add(1, std::sync::atomic::Ordering::Relaxed);
        let start = std::time::Instant::now();
        tracing::debug!(tool = %tool_name, "tool invocation started");
        let ctx = ToolCallContext::new(self, request, context);
        let result = Self::tool_router().call(ctx).await;
        let elapsed = start.elapsed();
        tracing::debug!(
            tool = %tool_name,
            elapsed_ms = elapsed.as_millis() as u64,
            is_error = result.as_ref().map_or(true, |r| r.is_error.unwrap_or(false)),
            "tool invocation completed"
        );

        // Centralized output redaction: apply to all text content so no
        // individual tool can accidentally leak secrets.
        if self.state.privacy.redaction_enabled {
            result.map(|mut r| {
                for item in &mut r.content {
                    if let RawContent::Text(ref mut tc) = item.raw {
                        tc.text = self.state.privacy.redact_output(&tc.text);
                    }
                }
                r
            })
        } else {
            result
        }
    }

    fn get_tool(&self, name: &str) -> Option<Tool> {
        if !self.state.privacy.is_tool_enabled(name) {
            return None;
        }
        Self::tool_router().get(name).cloned()
    }

    async fn list_resources(
        &self,
        _request: Option<PaginatedRequestParams>,
        _context: RequestContext<RoleServer>,
    ) -> Result<ListResourcesResult, ErrorData> {
        Ok(ListResourcesResult {
            resources: vec![
                RawResource::new(RESOURCE_URI_IPC_LOG, "ipc-log")
                    .with_description(
                        "Live IPC call log — all commands invoked between frontend and backend",
                    )
                    .with_mime_type("application/json")
                    .no_annotation(),
                RawResource::new(RESOURCE_URI_WINDOWS, "windows")
                    .with_description(
                        "Current state of all Tauri windows — position, size, visibility, focus",
                    )
                    .with_mime_type("application/json")
                    .no_annotation(),
                RawResource::new(RESOURCE_URI_STATE, "state")
                    .with_description(
                        "Victauri plugin state — event count, registered commands, memory stats",
                    )
                    .with_mime_type("application/json")
                    .no_annotation(),
            ],
            ..Default::default()
        })
    }

    async fn read_resource(
        &self,
        request: ReadResourceRequestParams,
        _context: RequestContext<RoleServer>,
    ) -> Result<ReadResourceResult, ErrorData> {
        let uri = &request.uri;
        let json = match uri.as_str() {
            RESOURCE_URI_IPC_LOG => {
                if let Ok(json) = self
                    .eval_with_return("return window.__VICTAURI__?.getIpcLog()", None)
                    .await
                {
                    json
                } else {
                    let calls = self.state.event_log.ipc_calls();
                    serde_json::to_string_pretty(&calls)
                        .map_err(|e| ErrorData::internal_error(e.to_string(), None))?
                }
            }
            RESOURCE_URI_WINDOWS => {
                let states = self.bridge.get_window_states(None);
                serde_json::to_string_pretty(&states)
                    .map_err(|e| ErrorData::internal_error(e.to_string(), None))?
            }
            RESOURCE_URI_STATE => {
                let state_json = serde_json::json!({
                    "events_captured": self.state.event_log.len(),
                    "commands_registered": self.state.registry.count(),
                    "memory": crate::memory::current_stats(),
                    "port": self.state.port.load(Ordering::Relaxed),
                });
                serde_json::to_string_pretty(&state_json)
                    .map_err(|e| ErrorData::internal_error(e.to_string(), None))?
            }
            _ => {
                return Err(ErrorData::resource_not_found(
                    format!("unknown resource: {uri}"),
                    None,
                ));
            }
        };

        let json = if self.state.privacy.redaction_enabled {
            self.state.privacy.redact_output(&json)
        } else {
            json
        };

        Ok(ReadResourceResult::new(vec![ResourceContents::text(
            json, uri,
        )]))
    }

    async fn subscribe(
        &self,
        request: SubscribeRequestParams,
        _context: RequestContext<RoleServer>,
    ) -> Result<(), ErrorData> {
        let uri = &request.uri;
        match uri.as_str() {
            RESOURCE_URI_IPC_LOG | RESOURCE_URI_WINDOWS | RESOURCE_URI_STATE => {
                self.subscriptions.lock().await.insert(uri.clone());
                tracing::info!("Client subscribed to resource: {uri}");
                Ok(())
            }
            _ => Err(ErrorData::resource_not_found(
                format!("unknown resource: {uri}"),
                None,
            )),
        }
    }

    async fn unsubscribe(
        &self,
        request: UnsubscribeRequestParams,
        _context: RequestContext<RoleServer>,
    ) -> Result<(), ErrorData> {
        self.subscriptions.lock().await.remove(&request.uri);
        tracing::info!("Client unsubscribed from resource: {}", request.uri);
        Ok(())
    }
}

/// Build a JS expression that takes an array of log entries (`source_expr`),
/// keeps at most `limit` of the most recent, and truncates any per-entry field
/// larger than [`MAX_LOG_FIELD_BYTES`]. This keeps IPC/network log results under
/// the eval size cap on busy apps where individual entries carry large bodies.
///
/// The returned code is a complete `return (...)` statement.
fn trimmed_log_js(source_expr: &str, limit: usize) -> String {
    let mb = MAX_LOG_FIELD_BYTES;
    format!(
        r"return (function() {{
            var MB = {mb};
            function trimField(v) {{
                if (typeof v === 'string') {{
                    return v.length > MB ? (v.slice(0, MB) + '…[+' + (v.length - MB) + ' bytes truncated]') : v;
                }}
                if (v && typeof v === 'object') {{
                    var s; try {{ s = JSON.stringify(v); }} catch (e) {{ s = ''; }}
                    if (s.length > MB) {{ return '[truncated ' + s.length + ' bytes]'; }}
                }}
                return v;
            }}
            function trimEntry(e) {{
                if (e == null || typeof e !== 'object') return e;
                var out = Array.isArray(e) ? [] : {{}};
                for (var k in e) {{ if (Object.prototype.hasOwnProperty.call(e, k)) out[k] = trimField(e[k]); }}
                return out;
            }}
            var arr = {source_expr} || [];
            if (arr.length > {limit}) arr = arr.slice(-{limit});
            return arr.map(trimEntry);
        }})()"
    )
}

/// Unwrap the `{"__victauri_ok": <val>, "__victauri_type": <t>}` (or
/// `{"__victauri_err": <msg>}`) envelope produced by the eval bridge into the
/// value/error string returned to callers.
///
/// Parsing uses `serde_json`'s default recursion limit (it is intentionally NOT
/// disabled — an unbounded recursive parse of a pathologically deep result
/// overflows the worker thread stack and crashes the host). When the parse
/// fails because the value is too deeply nested, the envelope is stripped by
/// string slicing (no recursion) so the actual value is still returned rather
/// than leaking the raw envelope string.
fn unwrap_eval_envelope(raw: String) -> Result<String, String> {
    if let Ok(envelope) = serde_json::from_str::<serde_json::Value>(&raw) {
        if let Some(err) = envelope.get("__victauri_err") {
            return Err(format!(
                "JavaScript error: {}",
                err.as_str().unwrap_or("unknown error")
            ));
        }
        if envelope.get("__victauri_ok").is_some() {
            let js_type = envelope
                .get("__victauri_type")
                .and_then(|t| t.as_str())
                .unwrap_or("value");
            return match js_type {
                "undefined" => Ok("undefined".to_string()),
                "null" => Ok("null".to_string()),
                _ => Ok(serde_json::to_string(&envelope["__victauri_ok"])
                    .unwrap_or_else(|_| "null".to_string())),
            };
        }
    }
    // Fallback for results too deeply nested for the recursion-limited parser.
    if let Some(after) = raw.strip_prefix(r#"{"__victauri_ok":"#)
        && let Some(idx) = after.rfind(r#","__victauri_type":"#)
    {
        return Ok(after[..idx].to_string());
    }
    if let Some(after) = raw.strip_prefix(r#"{"__victauri_err":"#) {
        let msg = after.trim_end_matches('}').trim_matches('"');
        return Err(format!("JavaScript error: {msg}"));
    }
    Ok(raw)
}

/// Statement keywords where a leading `return` would be a syntax error.
const STMT_STARTS: &[&str] = &[
    "return ",
    "return;",
    "return\n",
    "return\t",
    "if ",
    "if(",
    "for ",
    "for(",
    "while ",
    "while(",
    "switch ",
    "switch(",
    "try ",
    "try{",
    "const ",
    "let ",
    "var ",
    "function ",
    "function(",
    "function*",
    "class ",
    "throw ",
    "do ",
    "do{",
    "{",
    "async function",
    "debugger",
];

/// String/template/comment scan state for [`should_prepend_return`].
#[derive(PartialEq, Clone, Copy)]
enum ScanState {
    Code,
    SingleQuote,
    DoubleQuote,
    Template,
}

/// Decide whether to wrap `code` with a leading `return`.
///
/// Only a single bare expression should get `return` prepended. Code that is a
/// multi-statement block, contains an explicit top-level `return`, or starts
/// with a statement keyword is used as-is — prepending `return` to such code
/// would execute only the first statement and silently discard the rest.
///
/// The scan is string/template/comment-aware and only treats a `;` or an
/// explicit `return` token as significant when it occurs at bracket depth 0
/// outside of any string, template literal, or comment.
fn should_prepend_return(code: &str) -> bool {
    use ScanState::{Code, DoubleQuote, SingleQuote, Template};

    let code = code.trim();
    if code.is_empty() {
        return false;
    }

    if STMT_STARTS.iter().any(|k| code.starts_with(k)) {
        return false;
    }

    let bytes = code.as_bytes();
    let mut i = 0;
    let mut depth: i32 = 0;
    let mut state = ScanState::Code;

    let is_ident = |b: u8| b.is_ascii_alphanumeric() || b == b'_' || b == b'$';
    // Is there a top-level `return` token starting at byte `i` (word-bounded)?
    let is_return_token = |i: usize| -> bool {
        let prev_ok = i == 0 || !is_ident(bytes[i - 1]);
        prev_ok
            && code[i..].starts_with("return")
            && bytes.get(i + 6).copied().is_none_or(|b| !is_ident(b))
    };

    while i < bytes.len() {
        let c = bytes[i];
        match state {
            Code => match c {
                b'\'' => state = SingleQuote,
                b'"' => state = DoubleQuote,
                b'`' => state = Template,
                b'/' if i + 1 < bytes.len() && bytes[i + 1] == b'/' => {
                    while i < bytes.len() && bytes[i] != b'\n' {
                        i += 1;
                    }
                    continue;
                }
                b'/' if i + 1 < bytes.len() && bytes[i + 1] == b'*' => {
                    i += 2;
                    while i + 1 < bytes.len() && !(bytes[i] == b'*' && bytes[i + 1] == b'/') {
                        i += 1;
                    }
                    i += 2;
                    continue;
                }
                b'(' | b'[' | b'{' => depth += 1,
                b')' | b']' | b'}' => depth -= 1,
                // A top-level `;` with more code after it == multi-statement.
                b';' if depth <= 0 && !code[i + 1..].trim().is_empty() => return false,
                // An explicit top-level `return` token means the code already returns.
                b'r' if depth <= 0 && is_return_token(i) => return false,
                _ => {}
            },
            SingleQuote => {
                if c == b'\\' {
                    i += 1;
                } else if c == b'\'' {
                    state = Code;
                }
            }
            DoubleQuote => {
                if c == b'\\' {
                    i += 1;
                } else if c == b'"' {
                    state = Code;
                }
            }
            Template => {
                if c == b'\\' {
                    i += 1;
                } else if c == b'`' {
                    state = Code;
                }
            }
        }
        i += 1;
    }

    true
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn prepend_return_bare_expressions() {
        assert!(should_prepend_return("document.title"));
        assert!(should_prepend_return("5 + 5"));
        assert!(should_prepend_return("\"justexpr\""));
        assert!(should_prepend_return("await fetch('/x')"));
        assert!(should_prepend_return(
            "document.querySelectorAll('a').length"
        ));
        assert!(should_prepend_return("x ? a : b"));
        // Single trailing semicolon on a bare expression is still an expression.
        assert!(should_prepend_return("document.title;"));
        // Semicolons inside strings must not be treated as boundaries.
        assert!(should_prepend_return("'a;b;c'"));
        assert!(should_prepend_return("\"x;y\".length"));
        // IIFE workaround: the `;` lives inside the arrow body (depth > 0).
        assert!(should_prepend_return("(()=>{window.x=5; return 'ok'})()"));
    }

    #[test]
    fn no_prepend_for_statement_blocks() {
        // The original silent-corruption cases.
        assert!(!should_prepend_return(
            "localStorage.setItem('k','v'); return localStorage.getItem('k')"
        ));
        assert!(!should_prepend_return(
            "window.scrollTo(0,50); return window.scrollY"
        ));
        assert!(!should_prepend_return("console.log('x'); return 123"));
        assert!(!should_prepend_return("window.__z=7; return 'ok'"));
        // Explicit return without a preceding semicolon (newline-separated).
        assert!(!should_prepend_return("window.x = 5\nreturn window.x"));
    }

    #[test]
    fn no_prepend_for_statement_keywords() {
        assert!(!should_prepend_return("return 42"));
        assert!(!should_prepend_return("const x = 1; return x"));
        assert!(!should_prepend_return("let y = 2"));
        assert!(!should_prepend_return("var z = 3"));
        assert!(!should_prepend_return("if (x) { return 1 }"));
        assert!(!should_prepend_return("for (const x of y) doThing(x)"));
        assert!(!should_prepend_return("throw new Error('x')"));
        assert!(!should_prepend_return("function f(){}"));
        assert!(!should_prepend_return("{ a: 1 }")); // object-literal-as-block ambiguity → as-is
    }

    #[test]
    fn empty_code_no_prepend() {
        assert!(!should_prepend_return(""));
        assert!(!should_prepend_return("   "));
    }

    #[test]
    fn envelope_unwrap_value() {
        assert_eq!(
            unwrap_eval_envelope(r#"{"__victauri_ok":"4DA","__victauri_type":"value"}"#.into()),
            Ok("\"4DA\"".to_string())
        );
        assert_eq!(
            unwrap_eval_envelope(r#"{"__victauri_ok":42,"__victauri_type":"value"}"#.into()),
            Ok("42".to_string())
        );
    }

    #[test]
    fn envelope_unwrap_undefined_null() {
        assert_eq!(
            unwrap_eval_envelope(r#"{"__victauri_ok":null,"__victauri_type":"undefined"}"#.into()),
            Ok("undefined".to_string())
        );
        assert_eq!(
            unwrap_eval_envelope(r#"{"__victauri_ok":null,"__victauri_type":"null"}"#.into()),
            Ok("null".to_string())
        );
    }

    #[test]
    fn envelope_unwrap_error() {
        let r = unwrap_eval_envelope(r#"{"__victauri_err":"boom"}"#.into());
        assert!(r.unwrap_err().contains("boom"));
    }

    #[test]
    fn envelope_unwrap_deeply_nested_does_not_leak() {
        // Build an envelope whose value is nested far deeper than serde_json's
        // default recursion limit (128). The full parse fails, so the slice
        // fallback must return the value — NOT the raw `__victauri_ok` envelope.
        let mut value = String::from("0");
        for _ in 0..300 {
            value = format!("{{\"n\":{value}}}");
        }
        let raw = format!(r#"{{"__victauri_ok":{value},"__victauri_type":"value"}}"#);
        let out = unwrap_eval_envelope(raw).unwrap();
        assert!(
            out.starts_with(r#"{"n":"#),
            "deep value should be unwrapped, got: {}",
            &out[..out.len().min(40)]
        );
        assert!(
            !out.contains("__victauri_ok"),
            "envelope must not leak into the result"
        );
    }

    #[test]
    fn js_string_simple() {
        assert_eq!(js_string("hello"), "\"hello\"");
    }

    #[test]
    fn js_string_single_quotes() {
        let result = js_string("it's a test");
        assert!(result.contains("it's a test"));
    }

    #[test]
    fn js_string_double_quotes() {
        let result = js_string(r#"say "hello""#);
        assert!(result.contains(r#"\""#));
    }

    #[test]
    fn js_string_backslashes() {
        let result = js_string(r"path\to\file");
        assert!(result.contains(r"\\"));
    }

    #[test]
    fn js_string_newlines_and_tabs() {
        let result = js_string("line1\nline2\ttab");
        assert!(result.contains(r"\n"));
        assert!(result.contains(r"\t"));
        assert!(!result.contains('\n'));
    }

    #[test]
    fn js_string_null_bytes() {
        let input = String::from_utf8(b"before\x00after".to_vec()).unwrap();
        let result = js_string(&input);
        // serde_json escapes null bytes as
        assert!(result.contains("\\u0000"));
        assert!(!result.contains('\0'));
    }

    #[test]
    fn js_string_template_literal_injection() {
        let result = js_string("`${alert(1)}`");
        // Should not contain unescaped backticks that could break template literals
        // serde_json wraps in double quotes, so backticks are safe
        assert!(result.starts_with('"'));
        assert!(result.ends_with('"'));
    }

    #[test]
    fn js_string_unicode_separators() {
        // U+2028 (Line Separator) and U+2029 (Paragraph Separator) are valid in
        // JSON strings per RFC 8259, and serde_json passes them through literally.
        // Since js_string is used inside JS double-quoted strings (not template
        // literals), they are safe in modern JS engines (ES2019+).
        let result = js_string("a\u{2028}b\u{2029}c");
        // Verify the string is valid JSON that round-trips correctly
        let decoded: String = serde_json::from_str(&result).unwrap();
        assert_eq!(decoded, "a\u{2028}b\u{2029}c");
    }

    #[test]
    fn js_string_empty() {
        assert_eq!(js_string(""), "\"\"");
    }

    #[test]
    fn js_string_html_script_close() {
        // </script> in a JS string inside HTML could break out of script tags
        let result = js_string("</script><img onerror=alert(1)>");
        assert!(result.starts_with('"'));
        // The string is JSON-encoded; verify it round-trips safely
        let decoded: String = serde_json::from_str(&result).unwrap();
        assert_eq!(decoded, "</script><img onerror=alert(1)>");
    }

    #[test]
    fn js_string_very_long() {
        let long = "a".repeat(100_000);
        let result = js_string(&long);
        assert!(result.len() >= 100_002); // quotes + content
    }

    // ── URL validation tests ────────────────────────────────────────────────

    #[test]
    fn url_allows_http() {
        assert!(validate_url("http://example.com", false).is_ok());
    }

    #[test]
    fn url_allows_https() {
        assert!(validate_url("https://example.com/path?q=1", false).is_ok());
    }

    #[test]
    fn url_allows_http_localhost() {
        assert!(validate_url("http://localhost:3000", false).is_ok());
    }

    #[test]
    fn url_blocks_file_by_default() {
        let err = validate_url("file:///etc/passwd", false).unwrap_err();
        assert!(err.contains("file"), "error should mention the file scheme");
    }

    #[test]
    fn url_allows_file_when_opted_in() {
        assert!(validate_url("file:///tmp/test.html", true).is_ok());
    }

    #[test]
    fn url_blocks_javascript() {
        assert!(validate_url("javascript:alert(1)", false).is_err());
    }

    #[test]
    fn url_blocks_javascript_case_insensitive() {
        assert!(validate_url("JAVASCRIPT:alert(1)", false).is_err());
    }

    #[test]
    fn url_blocks_data_scheme() {
        assert!(validate_url("data:text/html,<script>alert(1)</script>", false).is_err());
    }

    #[test]
    fn url_blocks_vbscript() {
        assert!(validate_url("vbscript:MsgBox(1)", false).is_err());
    }

    #[test]
    fn url_rejects_invalid() {
        assert!(validate_url("not a url at all", false).is_err());
    }

    #[test]
    fn url_strips_control_chars() {
        // Control characters should be stripped, leaving a valid URL
        let input = format!("http://example{}com", '\0');
        assert!(validate_url(&input, false).is_ok());
    }

    // ── CSS color sanitization tests ───────────────────────────────────────

    #[test]
    fn css_color_valid_hex() {
        assert_eq!(sanitize_css_color("#ff0000").unwrap(), "#ff0000");
        assert_eq!(sanitize_css_color("#FFF").unwrap(), "#FFF");
        assert_eq!(sanitize_css_color("#12345678").unwrap(), "#12345678");
    }

    #[test]
    fn css_color_valid_rgb() {
        assert_eq!(
            sanitize_css_color("rgb(255, 0, 0)").unwrap(),
            "rgb(255, 0, 0)"
        );
        assert_eq!(
            sanitize_css_color("rgba(0, 0, 0, 0.5)").unwrap(),
            "rgba(0, 0, 0, 0.5)"
        );
    }

    #[test]
    fn css_color_valid_named() {
        assert_eq!(sanitize_css_color("red").unwrap(), "red");
        assert_eq!(sanitize_css_color("transparent").unwrap(), "transparent");
    }

    #[test]
    fn css_color_valid_hsl() {
        assert_eq!(
            sanitize_css_color("hsl(120, 50%, 50%)").unwrap(),
            "hsl(120, 50%, 50%)"
        );
    }

    #[test]
    fn css_color_rejects_too_long() {
        let long = "a".repeat(101);
        assert!(sanitize_css_color(&long).is_err());
    }

    #[test]
    fn css_color_rejects_backslash_escapes() {
        assert!(sanitize_css_color(r"red\00").is_err());
        assert!(sanitize_css_color(r"\72\65\64").is_err());
    }

    #[test]
    fn css_color_rejects_url_injection() {
        assert!(sanitize_css_color("url(http://evil.com)").is_err());
        assert!(sanitize_css_color("URL(http://evil.com)").is_err());
    }

    #[test]
    fn css_color_rejects_expression_injection() {
        assert!(sanitize_css_color("expression(alert(1))").is_err());
        assert!(sanitize_css_color("EXPRESSION(alert(1))").is_err());
    }

    #[test]
    fn css_color_rejects_import() {
        assert!(sanitize_css_color("@import url(evil.css)").is_err());
    }

    #[test]
    fn css_color_rejects_semicolons_and_braces() {
        assert!(sanitize_css_color("red; background: url(evil)").is_err());
        assert!(sanitize_css_color("red} body { color: blue").is_err());
    }

    #[test]
    fn css_color_rejects_special_chars() {
        assert!(sanitize_css_color("red<script>").is_err());
        assert!(sanitize_css_color("red\"onload=alert").is_err());
        assert!(sanitize_css_color("red'onclick=alert").is_err());
    }

    #[test]
    fn css_color_trims_whitespace() {
        assert_eq!(sanitize_css_color("  red  ").unwrap(), "red");
    }

    #[test]
    fn css_color_empty_string() {
        assert_eq!(sanitize_css_color("").unwrap(), "");
    }
}