supercode-harness 0.4.6

//! Tools the agent can call.
//!
//! A [`Tool`] is a named capability with a JSON-Schema input and an async
//! `execute`. The [`ToolRegistry`] holds the set offered to a model; built-ins
//! cover file read/write/edit, directory listing, glob, content search, and
//! shell execution. Every tool can be disabled or re-described per
//! [`crate::Config`], so the capability surface is entirely yours to shape.

mod builtins;
pub(crate) mod tiers;

use std::collections::HashMap;
use std::collections::HashSet;
use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex};

use async_trait::async_trait;

use crate::config::Config;
use crate::error::Result;
use crate::modules::ModuleId;

pub use builtins::{
    ApplyPatchTool, BashTool, EditFileTool, GlobTool, ListDirTool, PersistentShellTool,
    ReadFileTool, SearchTool, UpdatePlanTool, ViewImageTool, WebFetchTool, WebSearchTool,
    WriteFileTool, WEB_SEARCH_URL_ENV,
};
// P5-1 F4: `crate::agent`'s permissions gate needs to check an
// `apply_patch` envelope's write surface against `protected_paths` — not
// part of the crate's public tool-registration API, so `pub(crate)` rather
// than folded into the `pub use` list above.
pub(crate) use builtins::patch_target_paths;
// P5-6 (§2 module 4 `tools.background`): `crate::agent::Agent`'s
// `background_exec` intrinsic reuses `BashTool`'s own sandboxed-spawn
// builder rather than duplicating it — see that function's doc comment.
pub(crate) use builtins::build_sandboxed_sh;
pub use tiers::{minify as minify_tool_schema, SchemaTier};
// `SandboxPolicy` and `ToolContext` are defined below in this module.

/// P4c (COMPOSABLE-HARNESS-DESIGN.md S1.2/S3.1 `core.tools.read_file
/// multimodal`, S1.2 `view_image`): the sentinel prefix a tool's plain
/// `String` result carries when it is actually an image data URL rather
/// than ordinary text — `Agent::run_loop` detects this prefix (before
/// `cap_tool_output` ever sees it) and builds a `content_parts` image
/// block instead of a plain-text tool result. Using a control character
/// (`\u{1}`, SOH) as part of the marker keeps a false-positive collision
/// with real tool output astronomically unlikely without requiring a new
/// `Tool::execute` return type across all ten built-ins (an L-sized
/// trait-signature change this S-sized catalog item does not call for).
pub const MULTIMODAL_IMAGE_MARKER: &str = "\u{1}SUPERCODE_IMAGE_DATA_URL\u{1}";

/// P4c (S1.2 `core.tools.read_file.multimodal` / `view_image`): recognized
/// image file extensions (lowercase, no dot) — the same set CC/pi treat as
/// "images" for multimodal read (catalog D1 row 2's `✓*`/`✓*` variants).
pub const IMAGE_EXTENSIONS: &[&str] = &["png", "jpg", "jpeg", "gif", "webp", "bmp"];

/// Whether `path`'s extension is a recognized image type (case-insensitive).
pub fn is_image_path(path: &Path) -> bool {
    path.extension()
        .and_then(|e| e.to_str())
        .map(|e| IMAGE_EXTENSIONS.contains(&e.to_ascii_lowercase().as_str()))
        .unwrap_or(false)
}

/// The `image/<subtype>` MIME type for a recognized image extension, for
/// the `data:` URL — falls back to `png` for anything [`is_image_path`]
/// didn't already gate (defensive; never actually hit through
/// [`is_image_path`]'s own extension list).
pub fn image_mime_for(path: &Path) -> &'static str {
    match path
        .extension()
        .and_then(|e| e.to_str())
        .map(|e| e.to_ascii_lowercase())
        .as_deref()
    {
        Some("jpg") | Some("jpeg") => "image/jpeg",
        Some("gif") => "image/gif",
        Some("webp") => "image/webp",
        Some("bmp") => "image/bmp",
        _ => "image/png",
    }
}

/// P4c (S1.2 `core.tools.edit_file.notebook_aware`): the extension that
/// gates `EditFileTool`'s Jupyter cell-surgery branch.
pub const NOTEBOOK_EXTENSION: &str = "ipynb";

/// P4c (S2 module 5 `tools.web`, S2.1 dep "network sandbox rules", S17):
/// the network-domain policy a caller (SDK embedder) may install on a
/// [`ToolContext`] so [`crate::tools::WebFetchTool`]/[`crate::tools::WebSearchTool`]
/// respect it — see [`ToolContext::check_network`]. `None` on the context
/// (the default) means no policy is configured, matching today's honest
/// gap (no P5 `capabilities.permissions.sandbox.network` engine exists
/// yet, C3 — tracked, not hidden).
#[derive(Debug, Clone, Default)]
pub struct NetworkPolicy {
    /// Whether the policy is enforced at all. `false` behaves exactly like
    /// `None` on the context.
    pub enabled: bool,
    /// If non-empty, only these hosts (exact match) are allowed.
    pub allow_domains: Vec<String>,
    /// These hosts (exact match) are always denied, even if also present in
    /// `allow_domains`.
    pub deny_domains: Vec<String>,
}

/// Filesystem confinement applied to write-capable tools — the analog of
/// Codex's `read-only` / `workspace-write` / `danger-full-access` sandbox modes.
///
/// Enforced at the tool layer for file operations (`write_file`, `edit_file`,
/// `apply_patch`). Note: this confines the *file tools*; it does not OS-sandbox
/// arbitrary subprocesses (`bash`/`shell`) — true process isolation needs
/// platform primitives (seatbelt/landlock) and is a separate concern. Use
/// [`shell_sandbox_unenforceable`] as the runtime check for whether that gap
/// applies to the current platform and enabled tools.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum SandboxPolicy {
    /// No file writes are permitted by the file tools.
    ReadOnly,
    /// Writes are permitted only inside the working directory.
    WorkspaceWrite,
    /// No confinement (default — preserves prior behavior).
    #[default]
    DangerFullAccess,
}

/// P5-9 (design §2 module 20 `checkpoint`, §2.1 D-5 "write-path
/// interception seam shared with `formatters`"): the ONE well-defined
/// interception point around every file-mutating built-in tool
/// (`write_file`/`edit_file`/`apply_patch`) — installed on
/// [`ToolContext::write_observer`], `None` by default. Both hooks fire
/// AFTER [`ToolContext::check_write`] has already approved the call (so an
/// observer never sees a write the sandbox itself refused) and BEFORE/AFTER
/// the actual mutation:
/// - [`Self::before_write`] — pre-image capture. `crate::checkpoint`'s
///   [`crate::checkpoint::CheckpointObserver`] is the only implementation
///   today: it snapshots `path`'s current on-disk content (or records "did
///   not exist") so a later `checkpoint restore` can undo the write.
/// - [`Self::after_write`] — post-write. A true no-op in every
///   implementation shipped so far; reserved for `formatters` (P5-11,
///   design line 510 "shared seam with checkpoint") to run format-on-write
///   from, without needing a SECOND interception point wired through the
///   same three tools.
///
/// `None` (the default — `[capabilities.checkpoint]` off and no formatters
/// module yet) means neither hook is ever consulted: every write-tool
/// call-site's observer check is `if let Some(obs) = &ctx.write_observer`,
/// a branch that's simply never taken, so behavior is byte-identical to
/// before this seam existed.
///
/// P5-11 (§2 modules 28/29 `lsp`/`formatters`, C10): `async_trait` (rather
/// than the plain sync methods P5-9 originally shipped) because BOTH new
/// observers need real async I/O in `after_write` — `formatters` spawns and
/// awaits a subprocess, `lsp` writes/reads framed JSON-RPC over a child's
/// stdio — and neither can block the tokio runtime thread the way a
/// synchronous call from inside an already-`async fn execute()` would.
/// `CheckpointObserver`'s own hooks stay synchronous *internally* (plain
/// blocking `std::fs` calls); wrapping them in `async fn` changes nothing
/// observable for it, since that blocking work already ran on the calling
/// task before this signature changed. `after_write` now RETURNS
/// `Option<String>` — an annotation to append to the calling tool's result
/// string (formatter diff-back content, or LSP diagnostics) — `None` when
/// the observer has nothing to report, which is the only value
/// `CheckpointObserver::after_write` (still a no-op) ever returns, keeping
/// today's tool-result text byte-identical whenever checkpoint is the only
/// observer installed.
#[async_trait]
pub trait WriteObserver: Send + Sync + std::fmt::Debug {
    /// `path` (already resolved + sandbox-checked) is about to be
    /// created/overwritten/deleted. Implementations must be fast and must
    /// never propagate a failure as a tool error — a capture failure should
    /// degrade the OBSERVER (e.g. disable itself with a one-time warning),
    /// never block or fail the user's actual edit.
    async fn before_write(&self, path: &Path);
    /// `path` was just written/deleted successfully. Not called when the
    /// tool call itself failed (e.g. the write errored before completing).
    /// Returns an optional annotation for the calling tool's result text —
    /// see the trait doc comment above.
    async fn after_write(&self, path: &Path) -> Option<String>;
}

/// P5-11 (§2 modules 28/29, D-5 "shared write-path interception seam"): an
/// ORDERED chain of [`WriteObserver`]s installed as a single
/// `ToolContext::write_observer`, so the ONE seam P5-9 built keeps
/// supporting exactly one call site per tool while now composing multiple
/// concerns. Order is caller-determined (`crate::agent::build_tool_context`
/// builds it `checkpoint → formatters → lsp`, design's own required
/// ordering: checkpoint must capture the PRE-image before anything mutates
/// the file; formatters must run before lsp so diagnostics reflect the
/// FINAL, formatted file, not the model's pre-format draft).
/// `before_write` runs every observer in order; `after_write` runs every
/// observer in order too and joins any non-empty annotations with a blank
/// line, so a formatter's diff-back and an LSP diagnostics block can both
/// appear in one tool result without one silently discarding the other.
#[derive(Debug)]
pub struct WriteObserverChain(Vec<Arc<dyn WriteObserver>>);

impl WriteObserverChain {
    /// Build a chain that runs `observers` in order for both hooks.
    pub fn new(observers: Vec<Arc<dyn WriteObserver>>) -> Self {
        WriteObserverChain(observers)
    }
}

#[async_trait]
impl WriteObserver for WriteObserverChain {
    async fn before_write(&self, path: &Path) {
        for obs in &self.0 {
            obs.before_write(path).await;
        }
    }
    async fn after_write(&self, path: &Path) -> Option<String> {
        let mut notes: Vec<String> = Vec::new();
        for obs in &self.0 {
            if let Some(note) = obs.after_write(path).await {
                if !note.is_empty() {
                    notes.push(note);
                }
            }
        }
        if notes.is_empty() {
            None
        } else {
            Some(notes.join("\n\n"))
        }
    }
}

/// Ambient context passed to every tool invocation.
#[derive(Debug, Clone)]
pub struct ToolContext {
    /// The working directory tools resolve relative paths against.
    pub cwd: PathBuf,
    /// Filesystem confinement for write-capable tools.
    pub sandbox: SandboxPolicy,
    /// P4c (S1.2 `core.tools.read_file.multimodal`): whether `read_file`
    /// (and `view_image`, unconditionally) returns a recognized image file
    /// as a model-visible image content block. `false` (the default) is
    /// byte-identical to today's UTF-8-lossy-decode behavior.
    pub multimodal_read: bool,
    /// P4c (S1.2 `core.tools.edit_file.require_read_before_edit`, UNIQUE CC
    /// row): whether `edit_file` refuses a path not yet read this
    /// conversation. `false` (the default) is byte-identical to today's
    /// behavior — [`Self::read_paths`] is simply never consulted.
    pub require_read_before_edit: bool,
    /// P4c: canonicalized paths `read_file` has successfully read so far
    /// this conversation — shared (via `Arc<Mutex<_>>`) across every clone
    /// of this context, since `Agent` constructs one `ToolContext` at
    /// startup and reuses it for every tool call. Consulted by `EditFileTool`
    /// only when [`Self::require_read_before_edit`] is `true`.
    pub read_paths: Arc<Mutex<HashSet<PathBuf>>>,
    /// P4c (S1.2 `core.tools.edit_file.notebook_aware`, UNIQUE CC row
    /// "NotebookEdit"): whether `edit_file` accepts Jupyter cell
    /// replace/insert/delete operations against a `.ipynb` target. `false`
    /// (the default) is byte-identical to today's exact-string-replace-only
    /// behavior.
    pub notebook_aware: bool,
    /// P4c (S1.2 `core.shell_env_snapshot`): the user's captured
    /// interactive-shell environment, if [`crate::Config::shell_env_snapshot`]
    /// is on — `BashTool`/`PersistentShellTool` merge this into the spawned
    /// process's environment. `None` (the default) is byte-identical to
    /// today's behavior: no extra environment is injected.
    pub shell_env: Option<Arc<HashMap<String, String>>>,
    /// P4c (S1.4 `core.nested_instructions`, deferred from P4b): whether a
    /// file-touching tool injects an as-yet-unseen subdirectory's own
    /// `CLAUDE.md`/`AGENTS.md` into its result the first time a path under
    /// it is touched. `false` (the default) is byte-identical to today's
    /// behavior.
    pub nested_instructions: bool,
    /// P4c: subdirectories (relative to [`Self::cwd`]) whose nested
    /// instructions have already been injected this conversation — shared
    /// across clones, same rationale as [`Self::read_paths`]. Consulted only
    /// when [`Self::nested_instructions`] is `true`.
    pub injected_instruction_dirs: Arc<Mutex<HashSet<PathBuf>>>,
    /// P4c (S2 module 5 `tools.web`, S17): the network-domain policy
    /// `web_fetch`/`web_search` must respect, if one is configured. `None`
    /// (the default) means no policy is enforced — see [`NetworkPolicy`]'s
    /// doc comment for the honest-gap rationale.
    pub network_policy: Option<NetworkPolicy>,
    /// P4e (S3.1 `core.tools.bash.timeout_secs`, S14): the DEFAULT
    /// execution timeout (seconds) `BashTool::execute` falls back to when a
    /// model-issued call carries no `timeout_ms` argument of its own -- see
    /// `crate::config::ToolOverride::timeout_secs`. `None` (the default) is
    /// byte-identical to today's behavior: `BashTool`'s built-in
    /// `DEFAULT_BASH_TIMEOUT_MS` (120s) stands.
    pub bash_timeout_secs: Option<u64>,
    /// P5-9 (§2 module 20, D-5 shared write-path interception seam) — see
    /// [`WriteObserver`]'s doc comment. `None` (the default) is a true
    /// no-op: every write-tool call site's `if let Some(obs) = ...` branch
    /// is simply never taken.
    pub write_observer: Option<Arc<dyn WriteObserver>>,
    /// P5-10 (§2 module 12 `permissions.sandbox`): whether the OS-level
    /// backstop (Landlock/seatbelt) is engaged for the `bash`/`shell`
    /// subprocess — see `crate::sandbox::os_sandbox_active`. `None` (the
    /// default) preserves the pre-P5-10 trigger (confine whenever
    /// [`Self::sandbox`] isn't [`SandboxPolicy::DangerFullAccess`]).
    pub sandbox_os_enabled: Option<bool>,
    /// P5-10 (§2 module 12, `escalation`): what to do when a confining fs
    /// tier can't actually be enforced on this platform/kernel — see
    /// `crate::sandbox::SandboxEscalation`. Defaults to `Deny`
    /// (fail-closed).
    pub sandbox_escalation: crate::sandbox::SandboxEscalation,
    /// P5-10 (§2 module 12, `env_policy`): child-process environment
    /// sanitization for the spawned subprocess — see
    /// `crate::sandbox::SandboxEnvPolicy`. Defaults to `Inherit`
    /// (byte-identical to pre-P5-10 behavior).
    pub sandbox_env_policy: crate::sandbox::SandboxEnvPolicy,
    /// P5-10 (§2 module 12, `escalation = "ask"` → `permissions.approvals`,
    /// P5-1): the ambient handler `crate::sandbox::decide_fs` consults for
    /// an `ask`-tier sandbox-unenforceable decision. `None` (the default —
    /// no handler installed) is fail-closed, same posture as the P5-1 rule
    /// engine's own `Ask` tier with no handler.
    pub sandbox_approval_handler: Option<crate::sandbox::SandboxApprovalHandler>,
}

impl ToolContext {
    /// A context rooted at `cwd` with no confinement.
    pub fn new(cwd: impl Into<PathBuf>) -> Self {
        ToolContext {
            cwd: cwd.into(),
            sandbox: SandboxPolicy::DangerFullAccess,
            multimodal_read: false,
            require_read_before_edit: false,
            read_paths: Arc::new(Mutex::new(HashSet::new())),
            notebook_aware: false,
            shell_env: None,
            nested_instructions: false,
            injected_instruction_dirs: Arc::new(Mutex::new(HashSet::new())),
            network_policy: None,
            bash_timeout_secs: None,
            write_observer: None,
            sandbox_os_enabled: None,
            sandbox_escalation: crate::sandbox::SandboxEscalation::default(),
            sandbox_env_policy: crate::sandbox::SandboxEnvPolicy::default(),
            sandbox_approval_handler: None,
        }
    }

    /// P5-10: whether the OS-level backstop is active for this context —
    /// thin wrapper over `crate::sandbox::os_sandbox_active`.
    pub fn os_sandbox_active(&self) -> bool {
        crate::sandbox::os_sandbox_active(self.sandbox, self.sandbox_os_enabled)
    }

    /// P4c: record `path` (canonicalized if possible, else the resolved
    /// path as-is) as having been read this conversation — called by
    /// `ReadFileTool` on every successful read, unconditionally (cheap; the
    /// set is only ever CONSULTED when [`Self::require_read_before_edit`] is
    /// on, but recording it unconditionally means turning the knob on
    /// mid-conversation sees every read that already happened).
    pub fn mark_read(&self, path: &Path) {
        let key = std::fs::canonicalize(path).unwrap_or_else(|_| path.to_path_buf());
        if let Ok(mut set) = self.read_paths.lock() {
            set.insert(key);
        }
    }

    /// P4c: whether `path` was previously recorded via [`Self::mark_read`].
    pub fn was_read(&self, path: &Path) -> bool {
        let key = std::fs::canonicalize(path).unwrap_or_else(|_| path.to_path_buf());
        self.read_paths
            .lock()
            .map(|set| set.contains(&key))
            .unwrap_or(false)
    }

    /// P4c (S2.1 S17): does `url` pass `Self::network_policy`, if one is
    /// configured? `Ok(())` when no policy is set (the honest-gap default)
    /// or the policy is present-but-disabled; `Err` names the reason
    /// otherwise. A URL with no parseable host is denied whenever a policy
    /// is actively enforced (fail closed — an unparseable host can't be
    /// matched against an allowlist).
    pub fn check_network(&self, url: &str) -> Result<()> {
        check_network_policy(self.network_policy.as_ref(), url)
    }

    /// Resolve a possibly-relative path against the working directory.
    pub fn resolve(&self, path: &str) -> PathBuf {
        let p = PathBuf::from(path);
        if p.is_absolute() {
            p
        } else {
            self.cwd.join(p)
        }
    }

    /// Enforce the sandbox policy for a write to `path`. `Err` if denied.
    pub fn check_write(&self, path: &Path) -> Result<()> {
        match self.sandbox {
            SandboxPolicy::DangerFullAccess => Ok(()),
            SandboxPolicy::ReadOnly => Err(crate::error::Error::tool(
                "sandbox",
                "write denied: sandbox is read-only",
            )),
            SandboxPolicy::WorkspaceWrite => {
                if path_within(&self.cwd, path) {
                    Ok(())
                } else {
                    Err(crate::error::Error::tool(
                        "sandbox",
                        format!(
                            "write denied: {} is outside the workspace {}",
                            path.display(),
                            self.cwd.display()
                        ),
                    ))
                }
            }
        }
    }
}

/// P5-2 (§2 module 15, security note "remote MCP over http/sse: respect the
/// NetworkPolicy from P5-1 if one is active"): the same policy-and-url check
/// [`ToolContext::check_network`] performs, factored out to a free function
/// so `crate::mcp::McpClient::connect_http`/`connect_sse` can enforce the
/// identical allow/deny/SSRF floor a `web_fetch` call would get — one
/// enforcement point, not a second parallel one that could silently drift
/// from it.
pub(crate) fn check_network_policy(policy: Option<&NetworkPolicy>, url: &str) -> Result<()> {
    let Some(policy) = policy else {
        return Ok(());
    };
    if !policy.enabled {
        return Ok(());
    }
    check_host_against_policy(policy, url_host(url).as_deref())
}

/// P4c-review (MEDIUM/LOW follow-up, dep 8's neighboring `tools.web` SSRF
/// gap): the SAME allow/deny decision [`ToolContext::check_network`] applies
/// to the INITIAL url, factored out so [`network_checked_redirect_policy`]
/// can apply it to every REDIRECT hop too. Without this, `check_network`
/// validated only the url the caller passed in — once a real network policy
/// is wired up (P5), a denied host reachable only via an allowed host's HTTP
/// redirect (reqwest follows up to 10 by default) bypassed the check
/// entirely. `host: None` (unparseable/absent) fails closed, exactly like
/// `check_network`'s own prior inline behavior.
fn check_host_against_policy(policy: &NetworkPolicy, host: Option<&str>) -> Result<()> {
    let Some(host) = host else {
        return Err(crate::error::Error::tool(
            "network",
            "cannot determine host from url; denied under an active network policy",
        ));
    };
    let host = host.to_ascii_lowercase();
    if policy.deny_domains.iter().any(|d| d == &host) {
        return Err(crate::error::Error::tool(
            "network",
            format!("host `{host}` is denied by the active network policy"),
        ));
    }
    if !policy.allow_domains.is_empty() && !policy.allow_domains.iter().any(|d| d == &host) {
        return Err(crate::error::Error::tool(
            "network",
            format!("host `{host}` is not on the network policy's allowlist"),
        ));
    }
    Ok(())
}

/// P4c-review (MEDIUM/LOW follow-up): a `reqwest::redirect::Policy` for
/// `WebFetchTool`/`WebSearchTool`'s client that re-runs
/// [`check_host_against_policy`] (the exact same check
/// [`ToolContext::check_network`] applies to the initial url) against every
/// redirect hop's target host, refusing to follow one that a network policy
/// denies. `policy: None` (no policy configured) or a present-but-disabled
/// one behaves like reqwest's own default policy — follow, capped at the
/// same 10-hop limit `redirect::Policy::default()` uses (the crate's `custom`
/// variant does NOT enforce a redirect cap on its own — see its doc comment
/// — so this reimplements that cap by hand).
pub(crate) fn network_checked_redirect_policy(
    policy: Option<NetworkPolicy>,
) -> reqwest::redirect::Policy {
    const MAX_REDIRECTS: usize = 10; // matches reqwest::redirect::Policy::default()
    reqwest::redirect::Policy::custom(move |attempt| {
        if attempt.previous().len() >= MAX_REDIRECTS {
            return attempt.error("too many redirects");
        }
        if let Some(policy) = &policy {
            if policy.enabled {
                if let Err(e) = check_host_against_policy(policy, attempt.url().host_str()) {
                    return attempt.error(e.to_string());
                }
            }
        }
        attempt.follow()
    })
}

/// P4c (S2.1 S17): extract the host from an `http(s)://` URL — the smallest
/// parser that satisfies [`ToolContext::check_network`]'s needs without a
/// new `url`-crate dependency (matches this crate's existing `glob_match`
/// precedent of hand-rolling a small parser rather than reaching for a
/// dependency for an S-sized need). Returns `None` for anything that isn't
/// `http://`/`https://` or has an empty host component.
fn url_host(url: &str) -> Option<String> {
    let rest = url
        .strip_prefix("https://")
        .or_else(|| url.strip_prefix("http://"))?;
    let end = rest.find(['/', '?', '#']).unwrap_or(rest.len());
    let authority = &rest[..end];
    // Strip a `user:pass@` prefix and a `:port` suffix, keeping the host.
    let host_and_port = authority.rsplit('@').next().unwrap_or(authority);
    let host = host_and_port.split(':').next().unwrap_or(host_and_port);
    if host.is_empty() {
        None
    } else {
        Some(host.to_ascii_lowercase())
    }
}

/// True when the requested sandbox policy cannot be enforced for shell
/// subprocesses: a confining policy, a platform without an OS sandbox
/// primitive wired up (only macOS/seatbelt is, via `sandbox-exec`), and at
/// least one shell tool (`"bash"` or `"shell"`) enabled.
///
/// This is a pure function so it's mechanically testable on any host OS:
/// callers pass the platform (typically `std::env::consts::OS`) and the set
/// of enabled tool names rather than relying on `cfg!`/`target_os`. It does
/// not itself sandbox anything — it only tells embedders/CLIs whether the
/// gap documented on [`SandboxPolicy`] applies right now, so they can warn.
/// P5-10 (§2 module 12): `landlock_available` is the caller's REAL Linux
/// Landlock-availability probe (`crate::sandbox::landlock_available()`,
/// typically) — a PARAMETER, not an internal `cfg!`/probe call, same "pure,
/// mechanically testable" contract this function already had. Before
/// P5-10, `platform == "linux"` always meant "unenforceable" (no OS
/// primitive existed yet); now it means "unenforceable UNLESS Landlock is
/// actually available on this kernel" — a confining tier on a
/// Landlock-capable Linux box is REAL enforcement, not a gap, so this must
/// say `false` for it (never claim a gap that no longer exists).
/// `platform == "macos"` is unconditionally `false` regardless of this
/// parameter (seatbelt, a separate primitive, always exists there); every
/// other platform (including `platform == "linux"` with
/// `landlock_available == false`) is unaffected by this parameter and
/// keeps the pre-P5-10 "no primitive" answer.
pub fn shell_sandbox_unenforceable(
    policy: SandboxPolicy,
    platform: &str,
    tools_enabled: &[&str],
    landlock_available: bool,
) -> bool {
    policy != SandboxPolicy::DangerFullAccess
        && platform != "macos"
        && !(platform == "linux" && landlock_available)
        && tools_enabled.iter().any(|t| *t == "bash" || *t == "shell")
}

/// Whether `path` is inside `root`. SECURITY (safe-path consolidation,
/// LOWER-URGENCY fix folded into the permissions-gate CRITICAL fix): this
/// used to compare only LEXICALLY-normalized paths (`..` traversal caught,
/// but a pre-existing in-workspace symlink pointing outside `root` was NOT —
/// `link -> /etc` plus a write to `link/passwd` lexically normalizes to
/// `<root>/link/passwd`, which "starts with" `root` even though it actually
/// resolves outside it). Now delegates to `crate::safe_path::contained`,
/// which ALSO resolves symlinks along the longest existing ancestor (the
/// same proven dual lexical+resolved check `crate::checkpoint`'s P5-9 fix
/// uses), so a symlink escape is caught here too. A non-existent target
/// (e.g. a file about to be created) is still handled correctly.
fn path_within(root: &Path, path: &Path) -> bool {
    crate::safe_path::contained(root, path)
}

/// `pub(crate)`: also the lexical-`..`-collapse step
/// [`crate::checkpoint`]'s containment check builds on (P5-9) — one
/// normalizer, not a second hand-rolled one.
pub(crate) fn normalize(path: &Path) -> Option<PathBuf> {
    use std::path::Component;
    // Make absolute against CWD if needed (paths are already joined to cwd by
    // resolve(), but be defensive).
    let abs = if path.is_absolute() {
        path.to_path_buf()
    } else {
        std::env::current_dir().ok()?.join(path)
    };
    let mut out = PathBuf::new();
    for c in abs.components() {
        match c {
            Component::ParentDir => {
                out.pop();
            }
            Component::CurDir => {}
            other => out.push(other.as_os_str()),
        }
    }
    Some(out)
}

/// A callable capability.
#[async_trait]
pub trait Tool: Send + Sync {
    /// Stable, unique tool name (what the model calls).
    fn name(&self) -> &str;

    /// The built-in description. May be overridden via [`crate::Config`].
    fn description(&self) -> &str;

    /// JSON Schema describing the tool's input object.
    fn parameters(&self) -> serde_json::Value;

    /// Run the tool. Returns text to feed back to the model.
    async fn execute(&self, args: serde_json::Value, ctx: &ToolContext) -> Result<String>;
}

/// An ordered set of tools offered to the model.
#[derive(Default)]
pub struct ToolRegistry {
    tools: Vec<Box<dyn Tool>>,
}

impl ToolRegistry {
    /// An empty registry.
    pub fn new() -> Self {
        ToolRegistry::default()
    }

    /// A registry pre-populated with all built-in tools.
    pub fn with_builtins() -> Self {
        let mut r = ToolRegistry::new();
        r.register(ReadFileTool);
        r.register(WriteFileTool);
        r.register(EditFileTool);
        r.register(ListDirTool);
        r.register(GlobTool);
        r.register(SearchTool);
        r.register(ApplyPatchTool);
        r.register(BashTool::default());
        r.register(PersistentShellTool::default());
        r.register(UpdatePlanTool::default());
        r
    }

    /// P3 (COMPOSABLE-HARNESS-DESIGN.md §5.2 phase P3): build a registry
    /// from a resolved [`Config`]'s module-activation set, the intended
    /// replacement for unconditional [`Self::with_builtins`] call sites.
    ///
    /// **Mandatory risk-2 mitigation (§5.3 risk 2 — "land P3 behind
    /// `[experimental] module_registry = true`"):** when
    /// [`Config::module_registry`] is `false` (the default), this returns
    /// EXACTLY [`Self::with_builtins`] — same 10 tools, same order, zero
    /// behavior change. Only when the flag is explicitly on does
    /// [`Config::module_activation`]/[`Config::core_tools_enabled`] start
    /// shaping which tool objects get registered AT ALL: a disabled module
    /// contributes no tool (never registered, so never advertised and never
    /// mentioned anywhere) — e.g. `todos` off means `update_plan` is not in
    /// this registry; `tools_search` off (or its `list_dir`/`glob`/
    /// `content_search` sub-flags off) means the corresponding tool is
    /// absent too.
    pub fn from_config(config: &Config) -> Self {
        if !config.module_registry {
            return Self::with_builtins();
        }
        let mut r = ToolRegistry::new();
        let core_has = |name: &str| config.core_tools_enabled.iter().any(|t| t == name);
        let act = &config.module_activation;

        // Same relative order as `with_builtins()` for everything both paths
        // can register, so a partial activation set stays predictable.
        if core_has("read_file") {
            r.register(ReadFileTool);
        }
        if core_has("write_file") {
            r.register(WriteFileTool);
        }
        if core_has("edit_file") {
            r.register(EditFileTool);
        }
        // P4c (S1.2 `view_image`, S12): a fifth OPTIONAL default-tool name —
        // "recognized alongside read_file/bash/edit_file/write_file as a
        // fifth optional default-tool name, not a new module" — so it's
        // read from the SAME `core_tools_enabled` list as the other four,
        // not a `ModuleId`. Absent from the list by default (today's
        // `["read_file","bash","edit_file","write_file"]` default), so this
        // is a no-op unless a caller explicitly adds `"view_image"`.
        if core_has("view_image") {
            r.register(ViewImageTool);
        }
        if act.is_active(ModuleId::ToolsSearch) {
            if act.tools_search_list_dir {
                r.register(ListDirTool);
            }
            if act.tools_search_glob {
                r.register(GlobTool);
            }
            if act.tools_search_content_search {
                r.register(SearchTool);
            }
        }
        if act.is_active(ModuleId::ToolsApplyPatch) {
            r.register(ApplyPatchTool);
        }
        if core_has("bash") {
            r.register(BashTool::default());
        }
        if act.is_active(ModuleId::ToolsPersistentShell) {
            r.register(PersistentShellTool::default());
        }
        if act.is_active(ModuleId::Todos) {
            r.register(UpdatePlanTool::default());
        }
        // P4c (S2 module 5 `tools.web`, S4a "trivially addable"): single
        // tool each, gated by the module's own `fetch`/`search` sub-flags
        // (S3.1: `[capabilities.tools_web] { enabled = false, fetch = true,
        // search = true }`) exactly like `tools_search`'s three sub-flags.
        if act.is_active(ModuleId::ToolsWeb) {
            if act.tools_web_fetch {
                r.register(WebFetchTool);
            }
            if act.tools_web_search {
                r.register(WebSearchTool);
            }
        }
        r
    }

    /// Add a tool. A later registration with the same name shadows the earlier.
    pub fn register(&mut self, tool: impl Tool + 'static) {
        self.tools.push(Box::new(tool));
    }

    /// Look up a tool by name (last registration wins).
    pub fn get(&self, name: &str) -> Option<&dyn Tool> {
        self.tools
            .iter()
            .rev()
            .find(|t| t.name() == name)
            .map(|b| b.as_ref())
    }

    /// Iterate all tools.
    pub fn iter(&self) -> impl Iterator<Item = &dyn Tool> {
        self.tools.iter().map(|b| b.as_ref())
    }

    /// Number of registered tools.
    pub fn len(&self) -> usize {
        self.tools.len()
    }

    /// Whether the registry is empty.
    pub fn is_empty(&self) -> bool {
        self.tools.is_empty()
    }
}

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

    /// Truth table for [`shell_sandbox_unenforceable`]. Pure inputs — no
    /// `cfg!`/`target_os` gating — so this passes identically on macOS,
    /// Linux, and Windows CI hosts. P5-10 added the `landlock_available`
    /// parameter: a Linux host WITH Landlock is no longer a gap (this box
    /// IS one — see `sandbox::tests`/the integration test for the REAL
    /// enforcement proof); a Linux host WITHOUT it still is.
    #[test]
    fn shell_sandbox_unenforceable_truth_table() {
        // Confining policy + non-macOS + a shell tool enabled + Landlock
        // NOT available => true (still an honest gap).
        assert!(shell_sandbox_unenforceable(
            SandboxPolicy::ReadOnly,
            "linux",
            &["bash"],
            false,
        ));
        assert!(shell_sandbox_unenforceable(
            SandboxPolicy::WorkspaceWrite,
            "linux",
            &["shell"],
            false,
        ));
        // No Landlock concept on Windows at all — `landlock_available` is
        // irrelevant there (still unenforceable regardless of its value).
        assert!(shell_sandbox_unenforceable(
            SandboxPolicy::WorkspaceWrite,
            "windows",
            &["bash", "shell"],
            true,
        ));

        // P5-10: Linux WITH real Landlock support => NOT a gap anymore —
        // enforcement now exists, so this must say `false` (never claim a
        // gap that no longer applies).
        assert!(!shell_sandbox_unenforceable(
            SandboxPolicy::ReadOnly,
            "linux",
            &["bash"],
            true,
        ));
        assert!(!shell_sandbox_unenforceable(
            SandboxPolicy::WorkspaceWrite,
            "linux",
            &["shell"],
            true,
        ));

        // DangerFullAccess => false regardless of platform/tools/landlock.
        assert!(!shell_sandbox_unenforceable(
            SandboxPolicy::DangerFullAccess,
            "linux",
            &["bash", "shell"],
            false,
        ));

        // macOS => false regardless of policy (seatbelt sandboxes the
        // shell) — even with `landlock_available = true` passed in (an
        // impossible-in-practice combination, but the function must still
        // ignore it, since macOS's own primitive is what actually applies).
        assert!(!shell_sandbox_unenforceable(
            SandboxPolicy::ReadOnly,
            "macos",
            &["bash", "shell"],
            true,
        ));

        // No bash/shell in tools_enabled => false.
        assert!(!shell_sandbox_unenforceable(
            SandboxPolicy::ReadOnly,
            "linux",
            &[],
            false,
        ));
        assert!(!shell_sandbox_unenforceable(
            SandboxPolicy::ReadOnly,
            "linux",
            &["write_file"],
            false,
        ));
    }
}