Overview
dsh-tool-terminal
ctx.terminals: terminal_open, terminal_send, terminal_read, terminal_signal, terminal_close, and terminal_list. Every operation requires the exact initiating Agent, so a model cannot address another agent's terminal even if it learns the id.This is an atomic module already shipped with Harness, not a standalone profile layer.
Capabilities
What it contributes
README / EN
Package documentation
@deepseek-ai/dsh-tool-terminal
English | 中文
Six model-facing tools over ctx.terminals: terminal_open, terminal_send, terminal_read, terminal_signal, terminal_close, and terminal_list. Every operation requires the exact initiating Agent, so a model cannot address another agent's terminal even if it learns the id.
terminal_send(run_in_background: true) reuses ctx.jobs; job preflight and the PTY service's exclusive per-session send reservation occur before the job id is returned, completion is collected with job_output, and job_kill delivers SIGINT to the foreground process group. Foreground sends use terminal call/result cards. Background sends use a generic execute card; open, read, signal, close, and list use generic execute, read, execute, delete, and read cards respectively. None declares source locations.
Config
| key | default | meaning |
|---|---|---|
enableRunInBackground |
true |
expose and accept run_in_background; false omits the schema field and rejects a forced undeclared argument |
maxResultBytes |
262144 |
UTF-8 cap (minimum 64) for each complete terminal result or PTY job output after wait, session, pagination, truncation, and task-status metadata |
Both values are validated at load. The minimum result cap keeps every registry-issued session or job id visible in its creation acknowledgement. When a result exceeds maxResultBytes, rendering reserves space for control metadata and a truncation marker when they fit; cuts preserve UTF-8 boundaries. Each terminal definition's final-content callback applies the same cap after normalized pre-, around-, and post-execute policy failures, denials, short-circuits, replacements, or blocks; a structured multi-block policy result retains its shape.
Model Experience
System prompt
What the model sees
The plugin contributes this fixed guidance section:
Terminal guidance
Use a terminal session only when work needs persistent terminal state or interactive stdin; prefer shell/read/write/edit for bounded one-shot operations. Track every terminal session id and close sessions that no longer matter. An inferred_idle or timeout result does not prove the foreground command exited.
Token effect
Small fixed input cost on every request while the plugin is active.
KV Cache effect
Prefix-stable while the registration scope and guidance text are unchanged.
Tool schemas
What the model sees
The six generated schemas are listed in the dsh-tool-terminal catalog section. Their fixed schema tokens are present whenever this plugin is active; agent-scoped tool filtering may hide them.
Token effect
Fixed schema cost on requests where the tools are visible.
KV Cache effect
Prefix-stable while tool visibility and definitions are unchanged.
Tool results and task context
What the model sees
Spawn returns the id and bounded MOTD. Send/read return bounded terminal text plus readiness/history markers. Background mode returns a generic job id. Every terminal-owned or policy-produced single-text result is capped by maxResultBytes after normalized tool or pipeline errors, denials, short-circuits, replacements, blocks, and generic job status text. Structured multi-block policy results retain their shape. Results remain in session history until compaction; incremental task reads do not repeat consumed output. Programmatic callers receive typed session snapshots, bounded provider read/send DTOs, signal and close outcomes, or { kind: "background", jobId }; Native rendering applies the presentation cap above.
Token effect
Terminal-owned and policy-produced single-text results are data-dependent and bounded by maxResultBytes; a policy that deliberately substitutes structured multi-block content owns that content's bound. Each returned result remains in history until compaction.
KV Cache effect
Append-only; new results follow the reusable request prefix.
Known Limitations and Deferred Work
- No named key sequence, TUI, BEL, resize, auto-start, or cross-agent sharing schema is exposed.
- Background mode requires both
@deepseek-ai/dsh-jobsand its model-facing controller.
LIMITATIONS
Known limitations
- No named key sequence, TUI, BEL, resize, auto-start, or cross-agent sharing schema is exposed. - Background mode requires both `@deepseek-ai/dsh-jobs` and its model-facing controller.
