Executes bash command in shell session for terminal operations like git, bun, cargo, python.

- Use `cwd` to set working directory, not `cd dir && …` - Prefer `env: { NAME: "…" }` for multiline, quote-heavy, or untrusted values; reference as `$NAME` - Quote variable expansions like `"$NAME"` to preserve exact content - PTY mode is opt-in: set `pty: true` only when the command needs a real terminal (e.g. `sudo`, `ssh` requiring user input); default is `false` - Use `;` only when later commands should run regardless of earlier failures - Internal URIs (`skill://`, `agent://`, etc.) are auto-resolved to filesystem paths {{#if asyncEnabled}} - Use `async: true` for long-running commands when you don't need immediate output; the call returns a background job ID and the result is delivered automatically as a follow-up. {{/if}} - NEVER use Linux coreutils (`cat`, `head`, `tail`, `less`, `more`, `ls`, `grep`, `rg`, `awk`, `sed`, `find`, `fd`, etc.) when a dedicated tool suffices — ALWAYS prefer `read`, `search`, `find`, `edit`, `write`. - NEVER pipe through `| head -n N` or `| tail -n N` — output is already truncated with the full result available via `artifact://`. - NEVER redirect with `2>&1` or `2>/dev/null` — stdout and stderr are already merged. - Returns output and exit code. - Truncated output is retrievable from `artifact://` (linked in metadata) - Exit codes shown on non-zero exit

Timeout and async

timeout (seconds) caps the wall-clock duration of the command. When it elapses the process is killed and the call returns with a timeout annotation. Range: 1–3600s; default 300s (see clampTimeout("bash", …) in tool-timeouts.ts).
async: true only defers reporting of the result — it does NOT disable, extend, or detach the timeout. A daemon started with async: true is still killed when timeout elapses, regardless of how long the agent waits before reading the result.
For long-running daemons (dev servers, watchers): either pass an explicit large timeout (up to 3600), or fully detach the process from this shell using nohup … & / setsid … & / disown so it survives independent of the bash call's lifecycle. {{/if}}

Output minimizer

Bash stdout/stderr may be rewritten before you see it: long output is head/tail truncated, and test/lint runners (e.g. bun test, cargo test, ESLint) are passed through heuristic filters that drop noise and keep failures.
When the minimizer changes the visible text, the tool appends a [raw output: artifact://<id>] footer pointing at the full untouched capture. If a run looks suspicious (e.g. only a version banner) or you need the exact bytes, read that artifact.
If no footer is present, what you see is what the command actually emitted.