lean_ctx_server/tools/registered/

ctx_shell.rs

// SPDX-License-Identifier: Apache-2.0
use rmcp::ErrorData;
use rmcp::model::Tool;
use serde_json::{Map, Value, json};

use crate::server::tool_trait::{
    BackgroundJobState, BackgroundShellOutcome, McpTool, ShellOutcome, ToolContext, ToolOutput,
    get_bool, get_int, get_str,
};
use lean_ctx::tool_defs::tool_def;

use super::ctx_shell_background::{format_background_snapshot, redact_shell_output_secrets};

pub struct CtxShellTool;

/// Shell execution must never wait through the general-purpose session-lock
/// recovery window. The command can run without bookkeeping; cwd validation
/// cannot, so it fails promptly and lets the client retry.
const SESSION_LOCK_BUDGET: std::time::Duration = std::time::Duration::from_millis(250);

impl McpTool for CtxShellTool {
    fn name(&self) -> &'static str {
        "ctx_shell"
    }

    fn tool_def(&self) -> Tool {
        tool_def(
            "ctx_shell",
            "WORKFLOW: preferred — auto-compresses output (build/test/log).\n\
             Big logs: narrow the command (grep, sed -n, head/tail).\n\
             [exit:N] on errors (lossless).\n\
             POLICY: allowlisted read-only path.\n\
             A [BLOCKED] command is permanent; ctx_execute shares the same allowlist — fix with \
             `lean-ctx allow <cmd>`.\n\
             ANTIPATTERN: multi-line scripts, sh/bash script.sh, $var-as-command → ctx_execute \
             (when exposed).",
            json!({
                "type": "object",
                "properties": {
                    "command": { "type": "string", "description": "Shell command" },
                    "raw": { "type": "boolean", "description": "Exact bytes; only for diffs to apply, hashes, encoded output" },
                    "inline": { "type": "boolean", "description": "Verbatim up to archive.inline_max_bytes, else archived" },
                    "cwd": { "type": "string", "description": "Working dir (persists across calls)" },
                    "timeout_ms": { "type": "integer", "description": "Job lifetime in ms (max 3600000) — NOT the inline wait. A command still running at the ~110s foreground cap detaches to a pollable shell_* job and keeps running up to timeout_ms. Overridden by LEAN_CTX_SHELL_TIMEOUT_MS." },
                    "env": { "type": "object", "description": "Extra env vars", "additionalProperties": { "type": "string" } },
                    "run_in_background": { "type": "boolean", "description": "Detach immediately and return a job id. The command keeps timeout_ms (default here: the 1 h ceiling); poll or cancel with background_action and job_id." },
                    "background_action": { "type": "string", "enum": ["status", "cancel"], "description": "Inspect or cancel a background ctx_shell job; terminal status may include archiveId. Evicted/expired jobs return a structured lookup error." },
                    "job_id": { "type": "string", "description": "Job id returned by run_in_background." }
                }
            }),
        )
    }

    fn handle(
        &self,
        args: &Map<String, Value>,
        ctx: &ToolContext,
    ) -> Result<ToolOutput, ErrorData> {
        if let Some(message) = shell_access_denial(ctx) {
            return Ok(ToolOutput {
                shell_outcome: Some(ShellOutcome::Blocked),
                content_blocks: None,
                ..ToolOutput::simple(message)
            });
        }

        if let Some(action) = get_str(args, "background_action") {
            let id = get_str(args, "job_id").ok_or_else(|| {
                ErrorData::invalid_params("job_id is required with background_action", None)
            })?;
            let is_cancel = action == "cancel";
            let state = match action.as_str() {
                "status" => crate::server::background_shell::snapshot(&id),
                "cancel" => crate::server::background_shell::cancel_snapshot(&id),
                _ => {
                    return Err(ErrorData::invalid_params(
                        "background_action must be status or cancel",
                        None,
                    ));
                }
            };
            let (text, outcome) = format_background_snapshot(&id, is_cancel, state);
            return Ok(ToolOutput {
                shell_outcome: Some(outcome),
                content_blocks: None,
                // Looking after a running job is no new command: the session
                // stats leave it out (`server_metrics::counts_in_session`).
                mode: Some(crate::tools::server_metrics::BACKGROUND_POLL_MODE.to_string()),
                ..ToolOutput::simple(text)
            });
        }
        let command = get_str(args, "command")
            .ok_or_else(|| ErrorData::invalid_params("command is required", None))?;
        let timeout_ms = get_int(args, "timeout_ms").and_then(|n| u64::try_from(n).ok());

        // #1811: the write-doctrine guard classifies the *destination*, so a
        // relative redirect target only means something once it is placed
        // against the directory the command runs in. That directory is not the
        // `cwd` argument: `effective_cwd_checked` replaces a jail-rejected one
        // with the project root, and falls back to the session cwd when none
        // was passed. So it is resolved once, here, and the same value feeds
        // both the guard and the run below — resolving it twice would let the
        // two answers drift, and a guard that judged a directory the command
        // never ran in is exactly the bug #1811 reports.
        let explicit_cwd = get_str(args, "cwd");
        let had_explicit_cwd = explicit_cwd.is_some();
        // Without a session (one-shot CLI contexts) the run directory cannot be
        // resolved here. That is not an error yet — the cat-redirect below never
        // needs one — so the guard is simply told nothing and keeps its stricter
        // pre-#1811 refusal, and the session requirement is raised further down,
        // where running the command actually depends on it.
        let resolved_cwd = match ctx.session.as_ref() {
            Some(session_lock) => Some(tokio::task::block_in_place(|| {
                let guard = crate::server::bounded_lock::read_for(
                    session_lock,
                    "ctx_shell_cwd",
                    SESSION_LOCK_BUDGET,
                );
                resolve_effective_cwd(guard, explicit_cwd.as_deref())
            })?),
            None => None,
        };

        // The write-doctrine check (no `>`, `tee`, heredoc-to-file, curl -o, …)
        // is an MCP-payload-safety convention, not a security boundary, so it is
        // opt-out via `shell_allow_writes` (#523). The real command gating
        // (`check_shell_allowlist`, below) is NOT affected by this flag.
        let config = lean_ctx::core::config::Config::load();
        let mut write_allow_paths = config.shell_write_allow_paths_effective();
        // The session's project and the jail's allow entries are capture
        // targets too, so no project root is passed as a refusal below.
        write_allow_paths.extend(crate::tools::ctx_shell::capture_roots(
            &ctx.project_root,
            &ctx.extra_roots,
            &config,
        ));
        if !lean_ctx::core::config::shell_policy::allow_writes()
            && let Some(rejection) = crate::tools::ctx_shell::validate_command_in_cwd(
                &command,
                &write_allow_paths,
                None,
                resolved_cwd.as_ref().map(|(cwd, _)| cwd.as_str()),
            )
        {
            // The command never ran — report as a tool error so MCP clients
            // (guards, retry logic) can detect it programmatically (#389).
            return Ok(ToolOutput {
                shell_outcome: Some(ShellOutcome::Blocked),
                content_blocks: None,
                ..ToolOutput::simple(rejection)
            });
        }

        if let Some((lang, code, remainder)) = detect_heredoc_reroute(&command) {
            return tokio::task::block_in_place(|| {
                handle_interpreter_heredoc_reroute(args, ctx, &lang, &code, remainder)
            });
        }

        let grant = crate::server::shell_approval::current_grant();
        // Relative paths in the command resolve where it runs, not where
        // this server runs.
        let run_cwd = resolved_cwd
            .as_ref()
            .map(|(cwd, _)| std::path::PathBuf::from(cwd));
        if let Err(msg) = lean_ctx::core::shell_allowlist::with_run_cwd(run_cwd, || {
            lean_ctx::core::shell_allowlist::check_shell_allowlist_granted(&command, &grant)
        }) {
            // Independent `;`/newline statements: run the allowed ones and
            // name each skipped one, instead of refusing the whole line.
            if let Some(plan) = lean_ctx::core::shell_allowlist::partial_run(&command, &grant) {
                let mut sub = args.clone();
                sub.insert("command".into(), Value::String(plan.run));
                let mut output = self.handle(&sub, ctx)?;
                for note in &plan.skipped {
                    output.text.push('\n');
                    output.text.push_str(note);
                }
                // Part of the line did not run: never report the call as a
                // success. 126 is the shell's "found but cannot execute"; a
                // failure of the part that ran keeps its own code. The
                // ShellBlocked event was counted by the refusal above.
                if matches!(output.shell_outcome, None | Some(ShellOutcome::Exit(0))) {
                    output.shell_outcome = Some(ShellOutcome::Exit(126));
                }
                return Ok(output);
            }
            return Ok(ToolOutput {
                shell_outcome: Some(ShellOutcome::Blocked),
                content_blocks: None,
                ..ToolOutput::simple(msg.to_string())
            });
        }

        warn_shell_secret_paths(&command);

        // #842: a bare `cat <file>` is better served by ctx_read — it delivers
        // content inline instead of firewalling/archiving the output, avoiding
        // a mandatory ctx_expand round-trip for agents with cat-muscle-memory.
        if let Some(read_path) = detect_bare_cat_file(&command)
            && let Some(cache_lock) = ctx.cache.as_ref()
            && let Some(mut cache) = crate::server::bounded_lock::write(cache_lock, "cat_redirect")
        {
            let result = crate::tools::ctx_read::handle_with_task_resolved(
                &mut cache,
                &read_path,
                "full",
                crate::tools::CrpMode::Off,
                None,
            );
            let note = format!(
                "\n[ctx_shell: bare `cat` redirected to ctx_read for inline delivery. \
                         Use ctx_read(path=\"{read_path}\") directly next time.]"
            );
            let out = format!("{}{note}", result.content);
            let sent = lean_ctx::core::tokens::count_tokens(&out);
            return Ok(ToolOutput {
                text: out,
                original_tokens: sent,
                saved_tokens: 0,
                mode: Some("cat-redirect".to_string()),
                path: Some(read_path),
                changed: false,
                shell_outcome: Some(ShellOutcome::Exit(0)),
                content_blocks: None,
            });
        }

        tokio::task::block_in_place(|| {
            let session_lock = ctx
                .session
                .as_ref()
                .ok_or_else(|| ErrorData::internal_error("session not available", None))?;
            let Some((effective_cwd, cwd_jail_reason)) = resolved_cwd else {
                return Err(ErrorData::internal_error("session not available", None));
            };
            // A `cwd` rejected by the project-root jail is silently replaced with
            // the root (deliberate sandboxing). Surface that swap as a one-line
            // hint so the caller does not mistake the run dir for the requested
            // one (#629); appended at the end of the output like the other hints.
            let cwd_jail_reason_was_none = cwd_jail_reason.is_none();
            let cwd_jail_hint = cwd_jail_reason.map_or_else(String::new, |reason| {
                format!(
                    "\n[cwd: requested path rejected by project-root jail ({reason}) \u{2014} ran in {effective_cwd} instead]"
                )
            });

            {
                let Some(mut session) = crate::server::bounded_lock::write_for(
                    session_lock,
                    "ctx_shell_write",
                    SESSION_LOCK_BUDGET,
                ) else {
                    tracing::debug!("[ctx_shell: session lock timeout, proceeding without update]");
                    let cmd_clone = command.clone();
                    let cwd_clone = effective_cwd.clone();
                    let extra_env = match collect_extra_env(args) {
                        Ok(env) => env,
                        Err(message) => {
                            return Ok(ToolOutput {
                                shell_outcome: Some(ShellOutcome::Blocked),
                                content_blocks: None,
                                ..ToolOutput::simple(message)
                            });
                        }
                    };
                    let execution = crate::server::execute::execute_command_with_env_captured(
                        &cmd_clone, &cwd_clone, &extra_env, timeout_ms,
                    );
                    let admission = lean_ctx::core::context_admission::admit_tool_output(
                        &execution.output,
                        execution.completeness,
                    );
                    let output = redact_shell_output_secrets(&admission.rendered());
                    // Keep failure reporting consistent on this degraded path:
                    // same [exit:N] footer and the same structured outcome (#389).
                    let exit_suffix =
                        lean_ctx::shell::exit_status::exit_footer(execution.exit_code);
                    let final_text = format!("{output}{exit_suffix}");
                    let final_admission = lean_ctx::core::context_admission::admit_tool_output(
                        &final_text,
                        execution.completeness,
                    );
                    return Ok(ToolOutput {
                        shell_outcome: Some(ShellOutcome::Exit(execution.exit_code)),
                        content_blocks: None,
                        // Q13: the call's notice goes in front last, after
                        // admission; nothing above has seen it.
                        ..ToolOutput::simple(crate::server::execute::with_notice(
                            execution.notice,
                            final_admission.rendered(),
                        ))
                    });
                };
                // #707: a jail-accepted explicit `cwd` param is the client
                // telling us where it now works (worktree switches arrive
                // this way, not as `cd` commands) — persist it so path
                // resolution's divergence check tracks the live checkout.
                if had_explicit_cwd && cwd_jail_reason_was_none {
                    session.note_explicit_cwd(&effective_cwd);
                }
                session.update_shell_cwd(&command);
                let root_missing = session
                    .project_root
                    .as_deref()
                    .is_none_or(|r| r.trim().is_empty());
                if root_missing {
                    let home = dirs::home_dir().map(|h| h.to_string_lossy().to_string());
                    if let Some(root) =
                        lean_ctx::core::protocol::detect_project_root(&effective_cwd)
                        && home.as_deref() != Some(root.as_str())
                    {
                        session.project_root = Some(root.clone());
                        lean_ctx::core::index_orchestrator::ensure_all_background(&root);
                    }
                }
            }

            let arg_raw = get_bool(args, "raw").unwrap_or(false);
            let arg_bypass = get_bool(args, "bypass").unwrap_or(false);
            let env_disabled = std::env::var("LEAN_CTX_DISABLED").is_ok();
            let env_raw = std::env::var("LEAN_CTX_RAW").is_ok();
            let (raw, bypass) = resolve_shell_raw_flags(arg_raw, arg_bypass, env_disabled, env_raw);

            let crp_mode = ctx.crp_mode;
            let cmd_clone = command.clone();
            let cwd_clone = effective_cwd;
            let proactive_block = if raw
                || !lean_ctx::core::profiles::active_profile()
                    .output_hints
                    .proactive_context()
            {
                None
            } else {
                lean_ctx::core::relevance_tracker::proactive_context(&format!(
                    "ctx_shell command={cmd_clone} cwd={cwd_clone}"
                ))
            };

            let extra_env = match collect_extra_env(args) {
                Ok(env) => env,
                Err(message) => {
                    return Ok(ToolOutput {
                        shell_outcome: Some(ShellOutcome::Blocked),
                        content_blocks: None,
                        ..ToolOutput::simple(message)
                    });
                }
            };

            let inline = get_bool(args, "inline").unwrap_or(false);

            let auto_background = should_auto_background(&cmd_clone, timeout_ms);
            let detached = get_bool(args, "run_in_background").unwrap_or(false);
            if detached || auto_background {
                // A job the agent detached on purpose is long work: without a
                // stated lifetime it gets the ceiling, not the 2/10-minute
                // foreground default (25.10.: a release install was killed
                // after 10 of its ~35 minutes and nothing was installed).
                let lifetime = if detached {
                    timeout_ms.or(Some(lean_ctx::shell::exec::MAX_CALL_TIMEOUT_MS))
                } else {
                    timeout_ms
                };
                let job_id = crate::server::background_shell::start(
                    cmd_clone, cwd_clone, extra_env, lifetime,
                );
                let mode = if auto_background {
                    "auto-background"
                } else {
                    "background"
                };
                return Ok(ToolOutput {
                    shell_outcome: Some(ShellOutcome::Background(BackgroundShellOutcome {
                        state: BackgroundJobState::Running,
                        exit_code: None,
                        job_id: job_id.clone(),
                        archive_id: None,
                        archive_truncated: None,
                        captured_chars: None,
                        archived_chars: None,
                        summary: format!("{mode} job started"),
                        is_error: false,
                        display: None,
                    })),
                    content_blocks: None,
                    ..ToolOutput::simple(format!(
                        "[{mode}:{job_id} started — use ctx_shell(background_action=\"status\", job_id=\"{job_id}\") to poll or background_action=\"cancel\" to stop it]"
                    ))
                });
            }

            // Foreground runs still detach onto a pollable job if they outlast
            // the soft cap, so the MCP host's ~120s abort never strands the
            // result behind an unresolvable task id (#1106).
            //
            // #1173: `timeout_ms` is the *job's* lifetime, never the foreground
            // wait, so it must not raise this cap. Raising it bought no extra
            // inline wait — the host aborts at ~120s regardless — it only
            // suppressed our own detach, producing exactly the unresolvable
            // task id the cap exists to prevent. Separate knobs, one direction:
            // `LEAN_CTX_SHELL_FG_CAP_MS` moves the cap, `timeout_ms` does not.
            let soft_cap = std::time::Duration::from_millis(foreground_soft_cap_ms());
            let progress_sender = ctx.progress_sender.clone();
            let progress_label: String = cmd_clone.chars().take(60).collect();
            let cap_secs = soft_cap.as_secs_f64();
            let on_tick = |elapsed: std::time::Duration| {
                #[allow(clippy::unwrap_or_default)]
                if let Some(ref ps) = progress_sender
                    && let Some(sender) = ps
                        .lock()
                        .unwrap_or_else(std::sync::PoisonError::into_inner)
                        .as_ref()
                {
                    sender.send(
                        elapsed.as_secs_f64(),
                        Some(cap_secs),
                        Some(format!(
                            "ctx_shell: {}s elapsed — {progress_label}",
                            elapsed.as_secs()
                        )),
                    );
                }
            };
            let (process_output, exit_code, completeness, retained_withheld, containment_notice) =
                match crate::server::background_shell::run_foreground_or_detach_captured(
                    cmd_clone.clone(),
                    cwd_clone.clone(),
                    extra_env.clone(),
                    timeout_ms,
                    soft_cap,
                    Some(&on_tick),
                    ctx.cancel.as_ref(),
                ) {
                    crate::server::background_shell::CapturedForegroundResult::Finished {
                        output,
                        exit_code,
                        completeness,
                        retained_withheld,
                        notice,
                    } => (output, exit_code, completeness, retained_withheld, notice),
                    crate::server::background_shell::CapturedForegroundResult::Detached {
                        job_id,
                    } => {
                        return Ok(ToolOutput {
                            shell_outcome: Some(ShellOutcome::Background(BackgroundShellOutcome {
                                state: BackgroundJobState::Running,
                                exit_code: None,
                                job_id: job_id.clone(),
                                archive_id: None,
                                archive_truncated: None,
                                captured_chars: None,
                                archived_chars: None,
                                summary: "auto-detached job is still running".to_string(),
                                is_error: false,
                                display: None,
                            })),
                            content_blocks: None,
                            // #1173: a detach is not a failure — the command is
                            // alive and its output is recoverable, so say so
                            // rather than leaving the caller to infer a hang.
                            ..ToolOutput::simple(format!(
                                "[auto-background:{job_id} still running — passed the {}s foreground cap, not an error; output is kept and delivered by ctx_shell(background_action=\"status\", job_id=\"{job_id}\"), or background_action=\"cancel\" to stop it]",
                                soft_cap.as_secs()
                            ))
                        });
                    }
                };

            let display_input = if retained_withheld {
                "[lean-ctx gateway: retained output withheld by storage policy]".to_string()
            } else {
                process_output.clone()
            };
            let admission =
                lean_ctx::core::context_admission::admit_tool_output(&display_input, completeness);
            let output = redact_shell_output_secrets(&admission.rendered());
            let output = if raw {
                crate::server::walk_hint::strip_walk_hint(&output).to_string()
            } else {
                output
            };

            // Persistent diagnostics and derived stores require a separate,
            // pathless storage decision under one current policy epoch.
            let store = lean_ctx::core::context_admission::stores::StoreAdmission::current();
            let stored_command = store.admit_shell_command(&cmd_clone);
            let stored_output = (!retained_withheld)
                .then(|| store.admit_shell_output(&process_output, completeness))
                .flatten();
            let storage_allowed = !retained_withheld
                && store.is_current()
                && stored_command.is_some()
                && stored_output.is_some();
            let command_for_store = stored_command.as_deref().unwrap_or_default();
            let output_for_store = stored_output.as_deref().unwrap_or_default();
            if storage_allowed {
                lean_ctx::core::diagnostics_store::record_from_shell(
                    command_for_store,
                    output_for_store,
                    exit_code,
                );
            }

            let (result_out, original, saved, tee_hint) = if raw || inline {
                let tokens = lean_ctx::core::tokens::count_tokens(&output);
                (output, tokens, 0, String::new())
            } else {
                let _mode_guard = lean_ctx::core::savings_footer::ModeGuard::new("shell");
                let result =
                    crate::tools::ctx_shell::handle(&cmd_clone, &output, exit_code, crp_mode);
                let original = lean_ctx::core::tokens::count_tokens(&output);
                let sent = lean_ctx::core::tokens::count_tokens(&result);
                let saved = original.saturating_sub(sent);

                let cfg = lean_ctx::core::config::Config::load();
                // Shared tee policy (#811): identical decision to the CLI path —
                // `Failures` keys off the real exit code, not a substring match.
                let timeout_notice_only = is_timeout_notice_only(&output, exit_code);
                let tee_hint = if storage_allowed
                    && lean_ctx::shell::tee_policy::should_tee(
                        &cfg.tee_mode,
                        exit_code,
                        output.trim().is_empty() || timeout_notice_only,
                        lean_ctx::shell::tee_policy::output_was_elided(&output, &result),
                        original,
                        sent,
                    ) {
                    lean_ctx::shell::save_tee(command_for_store, output_for_store)
                        .map(|p| {
                            if lean_ctx::core::protected_store::enforce_protected_store_path(std::path::Path::new(&p)).is_err() {
                                format!("\n[full output: ctx_expand(id=\"{p}\", search=\"…\"|head=N|json_path=\"…\")]")
                            } else if matches!(cfg.tee_mode, lean_ctx::core::config::TeeMode::HighCompression)
                            {
                                let pct = lean_ctx::shell::tee_policy::savings_pct(original, sent);
                                // Recovery grammar is path-first: agents without ctx_expand
                                // can still read the saved artifact directly (#936).
                                format!(
                                    "\n[compressed {pct:.0}%: full output at {p} — read it directly (no MCP), or ctx_expand(id=\"{p}\", search=\"…\"|head=N|json_path=\"…\") for a slice]"
                                )
                            } else {
                                format!("\n[full output: {p} — read it directly (no MCP), or ctx_expand(id=\"{p}\")]")
                            }
                        })
                        .unwrap_or_default()
                } else {
                    String::new()
                };

                (result, original, saved, tee_hint)
            };

            let mode = if bypass {
                Some("bypass".to_string())
            } else if raw {
                Some("raw".to_string())
            } else {
                None
            };

            let shell_mismatch = if cfg!(windows) && !raw {
                shell_mismatch_hint(&command, &result_out)
            } else {
                String::new()
            };

            let result_out = lean_ctx::core::redaction::redact_text_if_enabled(&result_out);
            // #815: exit 124 = timeout signal (from timeout(1) / lean-ctx
            // shell timeout). Make it explicit so agents don't confuse a
            // timed-out command with a successful empty result.
            let exit_suffix = lean_ctx::shell::exit_status::exit_footer(exit_code);
            let nudge = if raw { "" } else { search_tool_nudge(&command) };
            let final_out = format!(
                "{result_out}{tee_hint}{shell_mismatch}{cwd_jail_hint}{nudge}{exit_suffix}"
            );
            let final_out = if let Some(block) = proactive_block {
                format!("{final_out}{block}")
            } else {
                final_out
            };
            let final_admission =
                lean_ctx::core::context_admission::admit_tool_output(&final_out, completeness);
            let final_out = final_admission.rendered();

            Ok(ToolOutput {
                // Q13: the call's notice goes in front last — after admission,
                // compression and the hints above, none of which has seen it.
                text: crate::server::execute::with_notice(containment_notice, final_out),
                original_tokens: original,
                saved_tokens: saved,
                mode,
                path: None,
                changed: false,
                shell_outcome: Some(ShellOutcome::Exit(exit_code)),
                content_blocks: None,
            })
        })
    }
}

/// Deny shell execution for explicitly restricted MCP clients. Missing client
/// context remains allowed so existing integrations retain their current access.
/// `ctx_execute` runs code too and applies the same gate (GHSA-rxv5-4c3x-g4q6 B).
pub(crate) fn shell_access_denial(ctx: &ToolContext) -> Option<String> {
    if let Some(role) = ctx.client_role.as_deref()
        && (role.eq_ignore_ascii_case("untrusted") || role.eq_ignore_ascii_case("readonly"))
    {
        return Some(format!(
            "[SHELL ACCESS DENIED] ctx_shell is unavailable to MCP clients with role '{role}'."
        ));
    }

    if ctx.shell_access == Some(false) {
        return Some(
            "[SHELL ACCESS DENIED] ctx_shell requires shell_access=true in the MCP session/request context."
                .to_string(),
        );
    }

    None
}

fn resolve_effective_cwd(
    session: Option<tokio::sync::OwnedRwLockReadGuard<lean_ctx::core::session::SessionState>>,
    explicit_cwd: Option<&str>,
) -> Result<(String, Option<String>), ErrorData> {
    match session {
        // A rejected directory fails here, before the write guard, the run,
        // a background job or the cache key see a substituted one.
        Some(session) => session
            .execution_cwd(explicit_cwd)
            .map(|cwd| (cwd, None))
            .map_err(|reason| {
                ErrorData::invalid_params(
                    format!("working directory rejected, command not run: {reason}"),
                    None,
                )
            }),
        None => Err(ErrorData::internal_error(
            "session lock timeout — cannot validate working directory",
            None,
        )),
    }
}

#[allow(clippy::fn_params_excessive_bools)]
fn resolve_shell_raw_flags(
    arg_raw: bool,
    arg_bypass: bool,
    _env_disabled: bool,
    env_raw: bool,
) -> (bool, bool) {
    let bypass = arg_bypass || env_raw;
    let raw = arg_raw || bypass;
    (raw, bypass)
}

/// A timeout notice is framework metadata, not recoverable command output. Do
/// not archive it as a tee artifact: expanding it cannot recover any bytes (#995).
///
/// Keyed on what precedes the marker rather than on the notice's exact shape,
/// so enriching it (the idle-timeout wording, the still-running segment list)
/// cannot silently turn every timeout back into an archived artifact (#1173).
fn is_timeout_notice_only(output: &str, exit_code: i32) -> bool {
    exit_code == 124
        && crate::server::execute::output_before_timeout_marker(output).is_some_and(str::is_empty)
}

fn search_tool_nudge(command: &str) -> &'static str {
    let cmd = command.trim();
    let first_word = cmd.split_whitespace().next().unwrap_or("");
    if !cmd.contains('|') {
        match first_word {
            "grep" | "rg" | "egrep" | "fgrep" | "ag" => {
                return "\n[hint: use ctx_search for structured, cached results with symbol/semantic modes]";
            }
            "find" => {
                return "\n[hint: use ctx_glob or ctx_tree for structured file discovery]";
            }
            "ls" | "exa" | "eza" => {
                return "\n[hint: use ctx_tree for structured directory listing]";
            }
            _ => {}
        }
    }
    ""
}

fn shell_mismatch_hint(command: &str, output: &str) -> String {
    let shell = lean_ctx::shell::shell_name();
    let is_posix = matches!(shell.as_str(), "bash" | "sh" | "zsh" | "fish");
    let has_error = output.contains("is not recognized")
        || output.contains("not found")
        || output.contains("command not found");

    if !has_error {
        return String::new();
    }

    let powershell_cmds = [
        "Get-Content",
        "Select-Object",
        "Get-ChildItem",
        "Set-Location",
        "Where-Object",
        "ForEach-Object",
        "Select-String",
        "Invoke-Expression",
        "Write-Output",
    ];
    let uses_powershell = powershell_cmds
        .iter()
        .any(|c| command.contains(c) || command.contains(&c.to_lowercase()));

    if is_posix && uses_powershell {
        format!(
            "\n[shell: {shell} — use POSIX commands (cat, head, grep, find, ls) not PowerShell cmdlets]"
        )
    } else {
        String::new()
    }
}

/// Collect the caller's `env` overrides, refusing protected keys by name instead
/// of dropping them silently (#1771).
///
/// The inline-override refusal in `core/shell_allowlist/enforcement.rs` points the
/// caller at this parameter and uses `PATH` as its worked example — yet five of the
/// nine variables it blocks inline (`PATH`, `GIT_SSH`, `GIT_SSH_COMMAND`,
/// `LD_PRELOAD`, `DYLD_INSERT_LIBRARIES`) are also in [`is_dangerous_env_key`].
/// Filtering them away meant the recommended recovery ran the command with the
/// ambient value and reported success, which is worse than the refusal it replaced:
/// a wrong result that looks right. Naming the key is the only honest outcome.
fn collect_extra_env(
    args: &Map<String, Value>,
) -> Result<std::collections::HashMap<String, String>, String> {
    let mut accepted = std::collections::HashMap::new();
    let Some(obj) = args.get("env").and_then(|v| v.as_object()) else {
        return Ok(accepted);
    };
    let mut rejected: Vec<&str> = Vec::new();
    for (key, value) in obj {
        let Some(text) = value.as_str() else { continue };
        if is_dangerous_env_key(key) {
            rejected.push(key.as_str());
            continue;
        }
        accepted.insert(key.clone(), text.to_string());
    }
    if rejected.is_empty() {
        return Ok(accepted);
    }
    rejected.sort_unstable();
    let names = rejected
        .iter()
        .map(|k| format!("`{k}`"))
        .collect::<Vec<_>>()
        .join(", ");
    let plural = if rejected.len() == 1 { "key" } else { "keys" };
    Err(format!(
        "ERROR: ctx_shell refuses the `env` {plural} {names} — nothing was run. These keys can \
         redirect which binary executes, so lean-ctx never forwards them, and the command would \
         otherwise have used the inherited value while appearing to honor yours. This is the \
         same rule that blocks the inline `KEY=value cmd` form; `env` is not a way around it. \
         Invoke the binary by its full path instead, or drop the override."
    ))
}

fn is_dangerous_env_key(key: &str) -> bool {
    const BLOCKED: &[&str] = &[
        // Dynamic linker injection
        "LD_PRELOAD",
        "LD_LIBRARY_PATH",
        "DYLD_INSERT_LIBRARIES",
        "DYLD_LIBRARY_PATH",
        "DYLD_FRAMEWORK_PATH",
        // Shell re-entry / startup injection
        "BASH_ENV",
        "ENV",
        "PROMPT_COMMAND",
        "SHELL",
        "IFS",
        "CDPATH",
        // Binary resolution hijacking
        "PATH",
        "GIT_EXEC_PATH",
        "GIT_SSH",
        "GIT_SSH_COMMAND",
        // Identity / home directory manipulation
        "HOME",
        "USER",
        "LOGNAME",
        "XDG_CONFIG_HOME",
        "XDG_DATA_HOME",
        "XDG_STATE_HOME",
        "XDG_CACHE_HOME",
        // Language runtime search path hijacking
        "PYTHONPATH",
        "PYTHONSTARTUP",
        "PYTHONHOME",
        "NODE_PATH",
        "NODE_OPTIONS",
        "RUBYOPT",
        "RUBYLIB",
        "GEM_PATH",
        "GEM_HOME",
        "PERL5LIB",
        "PERL5OPT",
        "CLASSPATH",
        "JAVA_HOME",
        "CARGO_HOME",
        "RUSTUP_HOME",
        "GOPATH",
        "GOROOT",
    ];
    let upper = key.to_uppercase();
    if BLOCKED.contains(&upper.as_str()) {
        return true;
    }
    if upper.starts_with("LD_") && upper.ends_with("_PATH") {
        return true;
    }
    // Block all lean-ctx config overrides from env
    if upper.starts_with("LEAN_CTX_") || upper.starts_with("LCTX_") {
        return true;
    }
    false
}

/// Warn when shell reads secret-like paths via cat/head/tail/less/more.
/// WARN-ONLY: command still executes, this is purely observational.
fn warn_shell_secret_paths(command: &str) {
    const READ_CMDS: &[&str] = &["cat", "head", "tail", "less", "more", "bat"];
    let segments = lean_ctx::core::shell_allowlist::extract_all_commands_pub(command);
    for seg in &segments {
        let trimmed = seg.trim();
        let tokens = lean_ctx::core::shell_allowlist::shell_tokenize(trimmed);
        if tokens.is_empty() {
            continue;
        }
        let base = tokens[0]
            .rsplit('/')
            .next()
            .unwrap_or(&tokens[0])
            .to_string();
        if !READ_CMDS.contains(&base.as_str()) {
            continue;
        }
        for tok in &tokens[1..] {
            if tok.starts_with('-') {
                continue;
            }
            let path = std::path::Path::new(tok.as_str());
            if lean_ctx::core::io_boundary::is_secret_like(path).is_some() {
                tracing::warn!(
                    "[SECURITY] Shell reading secret-like path: {tok} (command: {base})"
                );
            }
        }
    }
}

/// The Codex MCP client abandons a tool call after five minutes. A Cargo test
/// with an explicit five-minute-or-longer shell timeout cannot reliably finish
/// inside that transport deadline (and can wait on Cargo's target lock), so
/// detach it and return a pollable job instead.
fn should_auto_background(command: &str, timeout_ms: Option<u64>) -> bool {
    timeout_ms.is_some_and(|timeout| timeout >= 300_000)
        && command
            .lines()
            .any(|line| line.trim_start().starts_with("cargo test"))
}

/// Foreground wait budget before a still-running command is detached into a
/// pollable background job. Kept below the MCP host's ~120s tool-call abort so
/// the caller always receives a real `shell_*` job id instead of an
/// unresolvable task id (#1106). Override with `LEAN_CTX_SHELL_FG_CAP_MS`.
fn foreground_soft_cap_ms() -> u64 {
    std::env::var("LEAN_CTX_SHELL_FG_CAP_MS")
        .ok()
        .and_then(|v| v.parse().ok())
        .filter(|&ms| ms > 0)
        .unwrap_or(110_000)
}

/// Map an interpreter binary to a `ctx_execute` language name.
fn interpreter_to_execute_language(base: &str) -> Option<&'static str> {
    match base {
        "python" | "python2" | "python3" => Some("python"),
        "node" => Some("javascript"),
        "ruby" => Some("ruby"),
        _ => None,
    }
}

fn is_env_assignment_token(token: &str) -> bool {
    let unquoted: String = token.chars().filter(|c| *c != '"' && *c != '\'').collect();
    unquoted.contains('=')
        && !unquoted.starts_with('-')
        && !unquoted.starts_with('/')
        && !unquoted.starts_with('.')
}

/// Quote-aware scan for compound operators that would invalidate a reroute.
fn prelude_has_compound_operator(prelude: &str) -> bool {
    let bytes = prelude.as_bytes();
    let len = bytes.len();
    let mut i = 0;
    let mut in_single = false;
    let mut in_double = false;
    while i < len {
        let ch = bytes[i];
        if in_single {
            if ch == b'\'' {
                in_single = false;
            }
            i += 1;
            continue;
        }
        if in_double {
            if ch == b'\\' && i + 1 < len {
                i += 2;
            } else {
                if ch == b'"' {
                    in_double = false;
                }
                i += 1;
            }
            continue;
        }
        match ch {
            b'\'' => {
                in_single = true;
                i += 1;
            }
            b'"' => {
                in_double = true;
                i += 1;
            }
            b';' | b'|' | b'&' | b'(' | b'{' => return true,
            _ => i += 1,
        }
    }
    false
}

/// Detect interpreter heredoc patterns and extract the language + code body.
/// Returns `Some((language, code, remainder))` where remainder is any command
/// after the heredoc terminator that still needs shell execution.
fn detect_heredoc_reroute(command: &str) -> Option<(String, String, Option<String>)> {
    if !command.contains("<<") {
        return None;
    }

    let lines: Vec<&str> = command.lines().collect();
    if lines.is_empty() {
        return None;
    }

    let first_line = lines[0];
    let delims = lean_ctx::core::shell_allowlist::heredoc_delims(first_line, false);
    if delims.len() != 1 {
        return None;
    }
    let delim = delims[0].clone();

    let heredoc_pos = find_heredoc_operator(first_line)?;
    let prelude = first_line[..heredoc_pos].trim();
    if prelude_has_compound_operator(prelude) {
        return None;
    }

    let language = parse_interpreter_heredoc_prelude(prelude)?.to_string();

    if has_trailing_tokens_after_heredoc_delim(first_line, heredoc_pos) {
        return None;
    }

    let mut body = String::new();
    let mut remainder_start: Option<usize> = None;
    for (idx, line) in lines.iter().enumerate().skip(1) {
        if line.trim_start_matches('\t').trim() == delim {
            remainder_start = Some(idx + 1);
            break;
        }
        if !body.is_empty() {
            body.push('\n');
        }
        body.push_str(line);
    }
    let remainder_start = remainder_start?;
    let remainder = if remainder_start < lines.len() {
        let rest = lines[remainder_start..].join("\n");
        let rest = rest.trim();
        if rest.is_empty() {
            None
        } else {
            Some(rest.to_string())
        }
    } else {
        None
    };

    Some((language, body, remainder))
}

fn find_heredoc_operator(line: &str) -> Option<usize> {
    let bytes = line.as_bytes();
    let len = bytes.len();
    let mut i = 0;
    let mut in_single = false;
    let mut in_double = false;
    while i < len {
        let ch = bytes[i];
        if in_single {
            if ch == b'\'' {
                in_single = false;
            }
            i += 1;
            continue;
        }
        if in_double {
            if ch == b'\\' && i + 1 < len {
                i += 2;
            } else {
                if ch == b'"' {
                    in_double = false;
                }
                i += 1;
            }
            continue;
        }
        match ch {
            b'\'' => {
                in_single = true;
                i += 1;
            }
            b'"' => {
                in_double = true;
                i += 1;
            }
            b'<' if i + 1 < len && bytes[i + 1] == b'<' => {
                if i + 2 < len && bytes[i + 2] == b'<' {
                    i += 3;
                    continue;
                }
                return Some(i);
            }
            _ => i += 1,
        }
    }
    None
}

fn has_trailing_tokens_after_heredoc_delim(line: &str, heredoc_pos: usize) -> bool {
    let bytes = line.as_bytes();
    let mut i = heredoc_pos + 2;
    if i < bytes.len() && bytes[i] == b'-' {
        i += 1;
    }
    while i < bytes.len() && (bytes[i] == b' ' || bytes[i] == b'\t') {
        i += 1;
    }
    let Some((_, _, next)) = lean_ctx::core::shell_allowlist::read_heredoc_delim(bytes, i) else {
        return true;
    };
    !line[next..].trim().is_empty()
}

fn parse_interpreter_heredoc_prelude(prelude: &str) -> Option<&'static str> {
    let tokens = lean_ctx::core::shell_allowlist::shell_tokenize(prelude.trim());
    let mut idx = 0;
    while idx < tokens.len() && is_env_assignment_token(&tokens[idx]) {
        idx += 1;
    }
    if idx >= tokens.len() {
        return None;
    }
    let base = tokens[idx]
        .rsplit('/')
        .next()
        .unwrap_or(tokens[idx].as_str());
    let language = interpreter_to_execute_language(base)?;
    idx += 1;
    match tokens.get(idx) {
        None => Some(language),
        Some(dash) if dash == "-" => {
            if tokens.len() == idx + 1 {
                Some(language)
            } else {
                None
            }
        }
        Some(_) => None,
    }
}

/// The one working directory both halves of a rerouted heredoc call run in.
///
/// Resolution goes through the session so an explicit `cwd` is validated
/// against the configured roots, exactly as the non-rerouted path does. A `cwd`
/// the caller named that cannot be validated is an error, never a silent
/// substitution (#1666).
///
/// `Ok(None)` means only that no directory could be established without a
/// session. The heredoc-only path never needed one and must keep working; the
/// shell remainder always required a session and keeps requiring it.
fn resolve_reroute_cwd(
    ctx: &ToolContext,
    explicit_cwd: Option<&str>,
) -> Result<Option<String>, ErrorData> {
    let Some(session_lock) = ctx.session.as_ref() else {
        if explicit_cwd.is_some() {
            return Err(ErrorData::internal_error(
                "session not available — cannot validate the requested working directory",
                None,
            ));
        }
        return Ok(None);
    };
    let guard =
        crate::server::bounded_lock::read_for(session_lock, "ctx_shell_cwd", SESSION_LOCK_BUDGET);
    let (cwd, _) = resolve_effective_cwd(guard, explicit_cwd)?;
    Ok(Some(cwd))
}

fn handle_interpreter_heredoc_reroute(
    args: &Map<String, Value>,
    ctx: &ToolContext,
    language: &str,
    code: &str,
    remainder: Option<String>,
) -> Result<ToolOutput, ErrorData> {
    let timeout_ms = get_int(args, "timeout_ms").and_then(|n| u64::try_from(n).ok());
    let timeout_secs = timeout_ms.map(|ms| ms.div_ceil(1000).max(1));

    // #1666: resolve the working directory *before* the interpreter runs. The
    // shell remainder below always ran in the call's `cwd`; the rerouted
    // interpreter ran wherever the server process happened to sit. One tool
    // call, two directories — and a script using relative paths silently read
    // and wrote the wrong tree while reporting success.
    let explicit_cwd = get_str(args, "cwd");
    let exec_cwd = resolve_reroute_cwd(ctx, explicit_cwd.as_deref())?;

    let (exec_text, exec_outcome) = crate::tools::ctx_execute::handle_in(
        language,
        code,
        None,
        timeout_secs,
        exec_cwd.as_deref().map(std::path::Path::new),
    );
    let reroute_note = format!(
        "\n[ctx_shell: interpreter heredoc auto-rerouted to ctx_execute(language=\"{language}\")]"
    );
    let exec_completeness = lean_ctx::core::context_admission::OutputCompleteness {
        reader_incomplete: true,
        ..lean_ctx::core::context_admission::OutputCompleteness::complete()
    };
    let exec_admission =
        lean_ctx::core::context_admission::admit_tool_output(&exec_text, exec_completeness);
    let exec_text = lean_ctx::core::redaction::redact_text_if_enabled(&exec_admission.rendered());

    let Some(rest_cmd) = remainder else {
        let final_text = format!("{exec_text}{reroute_note}");
        let final_admission =
            lean_ctx::core::context_admission::admit_tool_output(&final_text, exec_completeness);
        let text = final_admission.rendered();
        return Ok(ToolOutput {
            original_tokens: lean_ctx::core::tokens::count_tokens(&text),
            text,
            saved_tokens: 0,
            mode: Some("heredoc-reroute".to_string()),
            path: None,
            changed: false,
            shell_outcome: Some(exec_outcome),
            content_blocks: None,
        });
    };

    if let Err(msg) = lean_ctx::core::shell_allowlist::check_shell_allowlist_granted(
        &rest_cmd,
        &crate::server::shell_approval::current_grant(),
    ) {
        let blocked =
            format!("{exec_text}{reroute_note}\n\n[remainder blocked by shell allowlist]\n{msg}");
        return Ok(ToolOutput {
            shell_outcome: Some(ShellOutcome::Blocked),
            content_blocks: None,
            ..ToolOutput::simple(blocked)
        });
    }

    // Unchanged from before #1666: running the shell remainder requires a
    // validated working directory.
    let effective_cwd =
        exec_cwd.ok_or_else(|| ErrorData::internal_error("session not available", None))?;

    let extra_env = match collect_extra_env(args) {
        Ok(env) => env,
        Err(message) => {
            return Ok(ToolOutput {
                shell_outcome: Some(ShellOutcome::Blocked),
                content_blocks: None,
                ..ToolOutput::simple(message)
            });
        }
    };

    let shell_execution = crate::server::execute::execute_command_with_env_captured(
        &rest_cmd,
        &effective_cwd,
        &extra_env,
        timeout_ms,
    );
    let shell_exit = shell_execution.exit_code;
    let shell_admission = lean_ctx::core::context_admission::admit_tool_output(
        &shell_execution.output,
        shell_execution.completeness,
    );
    let shell_output = redact_shell_output_secrets(&shell_admission.rendered());
    let arg_raw = get_bool(args, "raw").unwrap_or(false);
    let arg_bypass = get_bool(args, "bypass").unwrap_or(false);
    let env_disabled = std::env::var("LEAN_CTX_DISABLED").is_ok();
    let env_raw = std::env::var("LEAN_CTX_RAW").is_ok();
    let (raw, _) = resolve_shell_raw_flags(arg_raw, arg_bypass, env_disabled, env_raw);

    let shell_text = if raw {
        shell_output
    } else {
        crate::tools::ctx_shell::handle(&rest_cmd, &shell_output, shell_exit, ctx.crp_mode)
    };
    let shell_text = lean_ctx::core::redaction::redact_text_if_enabled(&shell_text);
    let exit_suffix = lean_ctx::shell::exit_status::exit_footer(shell_exit);

    let combined = format!(
        "{exec_text}{reroute_note}\n\n[heredoc remainder via ctx_shell]\n{shell_text}{exit_suffix}"
    );
    let mut completeness = shell_execution.completeness;
    // ctx_execute currently exposes no raw-byte capture flags for the heredoc
    // half, so the combined output cannot claim full inspection coverage.
    completeness.reader_incomplete = true;
    let final_admission =
        lean_ctx::core::context_admission::admit_tool_output(&combined, completeness);
    // Q13: the shell half's notice goes in front last, after admission.
    let text =
        crate::server::execute::with_notice(shell_execution.notice, final_admission.rendered());
    let token_count = lean_ctx::core::tokens::count_tokens(&text);
    Ok(ToolOutput {
        text,
        original_tokens: token_count,
        saved_tokens: 0,
        mode: Some("heredoc-reroute".to_string()),
        path: None,
        changed: false,
        shell_outcome: Some(ShellOutcome::Exit(shell_exit)),
        content_blocks: None,
    })
}

/// #842: detect a bare `cat <single_file>` command (no pipes, redirects, flags).
fn detect_bare_cat_file(command: &str) -> Option<String> {
    let trimmed = command.trim();
    let rest = trimmed.strip_prefix("cat ")?;
    let rest = rest.trim();
    if rest.is_empty()
        || rest.contains('|')
        || rest.contains('>')
        || rest.contains('<')
        || rest.contains(';')
        || rest.contains('&')
        || rest.contains('$')
        || rest.starts_with('-')
    {
        return None;
    }
    let parts: Vec<&str> = rest.split_whitespace().collect();
    if parts.len() != 1 {
        return None;
    }
    let file_path = parts[0].trim_matches(|c: char| c == '\'' || c == '"');
    if file_path.is_empty() {
        return None;
    }
    Some(file_path.to_string())
}

#[cfg(test)]
#[path = "ctx_shell_tests.rs"]
mod tests;