# Conflicts: # docs/rfc/proposed/2026-06-14-acp-multi-session.md # packages/acp/src/index.ts
@deepseek-ai/dsh-tool-bash
The model-facing bash tools — bash, bash_output, bash_kill — registered over the ctx.bash executor seam (@deepseek-ai/dsh-bash). Pure schema + text shaping; every process concern lives behind the seam, so sandboxed or remote executor implementations swap in without changing what the model sees.
Requires a loaded executor implementation (e.g. @deepseek-ai/dsh-bash-local); the plugin stays pending until ctx.bash exists (inject: ['tools', 'bash']).
Tools
bash
| Arg | Type | Notes |
|---|---|---|
command |
string (required) | Run via bash -c. No state persists between calls — use workdir, not cd. |
description |
string (required) | One-line, active-voice summary of the command (5-10 words), for UI/log display only — no effect on execution. |
timeoutMs |
number | Default/max from executor config (120s/600s for bash-local). |
workdir |
string | Working directory for this call. |
run_in_background |
boolean | Return a task id immediately; no timeout applies. |
command, workdir, and timeoutMs are resolved against the executor's config defaults via ctx.bash.resolve() before execution, so the executor seam (BashExecSpec) receives explicit workdir/timeoutMs values.
Result text: stdout, then a [stderr] section, then status markers — [timed out after Nms] whenever the executor's timer fired (reported independently of how the process ended, so a command that traps SIGTERM and exits 0 still shows it), [killed by signal: …] for a signal death, [exit code: N] for a non-zero exit (reported, not isError: the model decides how to react), and [output truncated; full output: <path>] when the tail was kept. Only infrastructure failures (spawn errors, aborts) surface as isError results.
bash_output
task_id → output produced since the previous bash_output call plus a status line (running / completed, exit code: N / killed). Reads that lost data to buffer bounds say so and point at the full-output spill file.
bash_kill
task_id → SIGTERM→SIGKILL on the task's process group. Killing an already-finished task is a reported no-op; unknown ids are errors.
Task ownership (cross-session isolation)
The owning agent is recorded per task id at spawn and kept for the lifetime of the loaded plugin instance (it is not cleared on completion). bash_output/bash_kill reject a task owned by a different agent with task <id> belongs to another session (a task started with no agent — a non-loop caller — has no owner and is open to anyone; a call with no exec.agent cannot access an owned task). Task ids are global and predictable, so under multi-session ACP this ownership check is the fence that stops one session's agent from reading or killing another session's background task. (TODO(tool-bash-owner-hmr): an independent HMR reload of this plugin starts a fresh map, so a task spawned before the reload becomes un-owned — acceptable as HMR is dev-only and the session boundary is one user's cooperative editor; a durable fix attaches ownership to the executor/task lifetime.)
Background completion notices
When a background task finishes, a short notice is injected into the owning agent's session (agent.inject(), source {kind: 'plugin', plugin: 'tool-bash'}). Injection is durable context for the next model request, not a wake-up — an idle agent stays idle until something sends a message. That's why the tool descriptions tell the model to poll with bash_output.
Permissions
TODO(permissions): commands run with the executor's full authority. The permission/sandbox seam is the tools/execute waterfall (veto or ask) plus sandboxing BashExecutor implementations — see docs/architecture.md. @cordisjs/plugin-capability (a named-permission service with a session test()) is a candidate building block for that work.