@deepseek-ai/dsh-bash
The bash executor seam: an abstract BashExecutor service (ctx.bash) defining WHAT a bash backend does — run commands, manage background tasks — without saying HOW.
This package is the interface quarter of the bash capability, split so each concern can evolve (and be swapped) independently:
| Package | Role |
|---|---|
@deepseek-ai/dsh-bash (this) |
the interface: abstract service + vocabulary types |
@deepseek-ai/dsh-bash-local |
an implementation: local subprocesses |
@deepseek-ai/dsh-bash-sandbox |
an implementation: dsh-bash-local's mechanics with every spawn confined via ctx.sandbox, denials reported as result facts |
@deepseek-ai/dsh-tool-bash |
the model-facing tool schemas over ctx.bash |
The split mirrors the LLM seam (LlmService/LlmAdapter) and the agent-tool survey: pi hides execution behind a BashOperations interface (local shell / SSH / VM backends), Codex behind an exec-server protocol. dsh-bash-sandbox is exactly that swap in action — a sandboxing executor behind the same interface, tool schemas untouched; a containerized or remote executor slots in the same way.
Service API (ctx.bash)
| Member | Semantics |
|---|---|
run(spec) |
Foreground execution. Resolves when the command finishes. Rejects only for infrastructure failures (unusable workdir, missing shell, pre-aborted signal); nonzero exits, timeout kills, and abort kills resolve with a descriptive BashRunResult. |
start(spec) |
Background execution. Returns a BashTask handle immediately; no timeout applies (stop tasks via kill). |
get(id) / list() |
Task lookup. |
sandboxMode |
The capability fact for the tool layer: the default mode a SANDBOXING executor confines under (undefined in the base class — "this executor does not sandbox"). dsh-tool-bash reads it at registration to advertise the escalation fields only when the composition honors them. |
ownerOf(id) |
The opaque OWNER token recorded for a background task at start (from the spec's owner), or undefined for an unknown id OR a known-but-ownerless task. The executor stores/returns it verbatim and NEVER interprets it — the access POLICY lives in the consumer (dsh-tool-bash), which compares ownerOf(id) to the caller's token. Storing ownership here (disposed with the executor's fiber) is what makes it survive a consumer HMR reload. |
readOutput(id) |
Incremental output read — consecutive reads never re-deliver. Reads that lost data to buffer bounds flag lossy and point at full-stream spill files. Throws for unknown ids. |
kill(id) |
Kill a running task. Returns false when it already finished; throws for unknown ids. |
onTaskDone(listener) |
Completion listener (effect-based, disposer returned). Fires exactly once per task; never after the service is disposed. |
Implementations subclass BashExecutor, implement the abstract methods, and call notifyTaskDone(task) on background completion. Disposal must kill every running task (no orphan processes) — see the HMR-safety tests.
Vocabulary
BashExecRequest (command, workdir?, timeoutMs?, signal?, stdin?, env?, owner?, sandboxMode?) resolves to BashExecSpec (command, workdir, timeoutMs, signal?, stdin?, env?, owner, sandboxMode) before execution; owner and sandboxMode are optional on the request and required-but-nullable on the resolved spec, so a forgotten one is a visible undefined rather than a silently-absent property. sandboxMode is the explicit per-call sandbox-policy input: an escalation grant a human just issued (the sandbox RFC § Escalation, which outranks) or the session's standing override (the sandbox RFC § Per-session mode switching); a sandboxing executor's resolve() stamps its configured default when the request carries none, and a non-sandboxing executor carries the field verbatim and confines nothing.
The seam also owns the per-session mode override vocabulary (the sandbox RFC § Per-session mode switching): the log-only 'bash/sandbox-mode' session event, the pure fold effectiveSandboxMode(events) (last event wins; undefined means "apply the executor default"), and THE write path setSandboxMode(session, mode) — the session log is the store, so an override survives restart by replay and two sessions can never see each other's mode. Writers must respect turn-enclosure: the ACP bridge anchors an idle switch at the next turn rather than appending between turns. The task id (BashTaskId) and the owner token (OwnerToken) are branded — OwnerToken is a DISTINCT brand from SessionId (the seam never imports dsh-session; the dsh-tool-bash consumer is the single boundary that casts its SessionId into one). run() returns BashRunResult (exitCode, signal, timedOut, aborted, timeoutMs, stdout/stderr as CollectedOutput) and start()/readOutput() use BashTask/BashTaskRead for the background side. A sandboxing executor additionally stamps sandbox result facts on results and settled tasks (BashSandboxInfo: the mode it executed under, the conservative denied classification, and — for confined modes — the backend's enforcement completeness); the mode/enforcement vocabulary is owned by the dsh-sandbox seam, and the facts are documented in core-data-structures/bash.md. See src/types.ts for the full contracts.
stdin and env are set by in-process plugins (the hooks bridges, native plugins) to feed a hook command its JSON payload on stdin and its CLAUDE_PROJECT_DIR/CLAUDE_PLUGIN_ROOT env. The model-facing dsh-tool-bash tool does not expose them as parameters — a model already has equivalent power through shell syntax (FOO=bar cmd, a heredoc), so they would be redundant tool params. This is not a security boundary: the implementation's credential scrub (not these fields) is what keeps the harness's ambient secrets out of a spawned command. They are plain optionals on the resolved spec (unlike owner's required-but-nullable): a missing one means "none", the safe default. See the bash-stdin-env RFC.