Yichen Jiang
a8dc6f9776
tool-bash-persistent overwrote the backend's PS1, so terminal-bash prompt readiness never matched and every send degraded to the 3.5s silence tier (idleSilenceMs + handoffGraceMs) under production defaults. The controlled PROMPT_COMMAND now re-asserts PS1 before every prompt, so an in-shell override never survives to the next prompt. The tool initializes with stty -echo alone and detects the no-end-marker fallback through the seam's stdin_read wait reason instead of matching its own prompt text. Tool calls drop from 7180/3560/3566 ms to 355/88/91 ms (spawn+init+echo, echo, pwd; darwin, production defaults). The loader composition suite now pins the fast path by pushing idleSilenceMs beyond the send bound, and a real-PTY case proves PS1 self-healing. Fixes #2585
3.1 KiB
@deepseek-ai/dsh-tool-bash-persistent
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Model-facing bash(command) backed by one owner-scoped ctx.terminals shell. The package owns the tool contract and shell reuse; deployments select the PTY backend and sandbox policy.
Config
| Key | Default | Meaning |
|---|---|---|
backendType |
shell |
Registered PTY backend used for each Agent shell. |
timeoutMs |
300000 |
Wall-clock limit for one command; timeout closes the shell. |
maxOutputChars |
16000 |
Maximum retained command-output characters; fixed diagnostics are added afterward. |
description |
Persistent-shell description | Model-facing environment contract. |
Model Experience
Tool schema
What the model sees
The generated bash schema, including the configured description. The plugin contributes no standalone system-prompt section; the deployment owns persona and environment guidance.
Token effect
Fixed schema cost while bash is visible.
KV Cache effect
Prefix-stable while the configured description and schema remain unchanged.
Tool results
What the model sees
Commands share one shell per Agent, so cwd, exported variables, activated environments, functions, and background jobs persist across calls. Results exclude private completion markers. When the shell reads stdin again without having printed the completion marker — after exec, an interrupt, or an interactive foreground child whose stdin wait the provider proves — the call returns the captured partial output, which can end with the backend's own prompt text. A nonzero wrapped command appends [exit code: N]; a shell that exits before reporting that status instead appends [shell exited: code N], [shell killed by signal: SIG], or [shell exited] when the backend supplies neither, then resets and tells the model that the next call starts fresh. Long output keeps the earliest retained prefix plus a clipping notice. If the PTY has already dropped that prefix, the result says so explicitly instead of presenting a tail as complete output. Timeout returns bounded partial output, closes the uncertain shell, and reports the reset.
Token effect
Data-dependent. maxOutputChars bounds retained command output; fixed clipping, lost-prefix, status, timeout, and reset diagnostics can extend the result.
KV Cache effect
Append-only tool results follow the reusable request prefix.
Known Limitations and Deferred Work
- The tool requires an owning Agent and a real PTY backend.
- An interactive foreground child (for example a REPL) returns early with partial output only where the subprocess provider proves its stdin wait; elsewhere the call runs to
timeoutMs. - Explicit
exitand timeout discard shell state. Cancellation also resets and discards the result, even when a complete status marker is already observable; the next call starts a fresh shell. - Environment facts such as network access and package mirrors belong in the configured
description, not this package's default.