deepseek-harness/packages/tasks/tool-tasks

@deepseek-ai/dsh-tool-tasks

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The model-facing control surface for ctx.tasks: three kind-independent tools, completion notices, and one background-work prompt section. Loading the plugin attaches the surface required by ctx.tasks.start().

Tools

• task_output(task_id, wait?, timeout_ms?) reads without blocking by default. Stream tasks return only the next delta; final-output tasks return their result after settlement. Every response ends with [status: ...]. wait: true waits up to the configured cap and leaves a still-running task alive on timeout.
• task_list() returns caller-visible tasks as <id> [<kind>] <status> — <label>.
• task_kill(task_id, reason?) requests cancellation immediately and forwards the logged reason. Terminal tasks return a non-consuming snapshot.

All three use generic UI cards: read for output and list, execute for kill.

Their canonical values are { text, task }, PublicTaskSnapshot[], and { outcome: 'cancellation-requested' | 'already-finished', task }. A public snapshot carries id, kind, label, status/detail, and start/finish times; it deliberately omits ownerSession and the internal reported notice bit. Native renderers preserve the status and acknowledgement text above.

When a producer supplies outputLimitBytes, task_output, terminal task_kill, and completion notices cap the complete Native UTF-8 result after adding status or notice text. Reads retain the output tail and control suffix when they fit; a bounded completion notice instead reserves background task <id> and the task_output collection instruction before spending remaining bytes on its variable kind, label, status, detail, and truncation marker. A prepended pre-execute listener captures the caller-visible task before policy, and each task-control definition's final-content callback applies its producer cap to single-text denials, short-circuits, normalized tool or pipeline failures, replacements, and blocks; structured multi-block policy results retain their shape. An existing producer truncation marker is reused rather than duplicated. Producers that omit the field retain the existing unbounded control-surface behavior.

Completion notices

An unreported completion injects background task <id> (<kind>: <label>) finished [status: ...]. Read its output with task_output. into the exact owner's session. When bounded, the stable id prefix and collection command outrank variable label/detail so the notice remains actionable at PTY's supported 64-byte minimum. Injection is durable context for the next request, not a wake-up. A kill or terminal read/wait marks delivery reported and suppresses the redundant notice; owner-disposal races are contained.

Config

key	default	meaning
waitTimeoutMs	30000	wait used when wait: true omits timeout_ms
maxWaitTimeoutMs	600000	cap for model-supplied waits

A default above the cap fails at load.

Model Experience

System prompt

What the model sees

Every request in this plugin's registration scope contains this guidance. Agent-scoped tool filtering may hide the tools without removing the independently registered prompt section.

Background-task guidance

Track every background task id you start. You are notified in-session when a task finishes — do not busy-poll or sleep on one; keep working on independent steps and do not duplicate a running task's work. Before giving a final answer, collect every still-relevant task with task_output (set wait: true only when you are genuinely blocked on it), and task_kill tasks that stopped mattering.

Token effect

Small fixed input cost per request while active.

KV Cache effect

Prefix-stable while the plugin scope and guidance text are unchanged. Activation or disposal may invalidate reuse from this prompt section.

Tool schemas

What the model sees

The generated task_output, task_list, and task_kill schemas while this surface is visible.

Token effect

Fixed schema cost on each request where the tools are visible.

KV Cache effect

Prefix-stable while tool definitions and visibility are unchanged. Registration lifecycle or scoped restrictions may invalidate reuse from the first changed schema token.

Results and notices

What the model sees

Reads return output or (no new output) followed by [status: <status>] and optional detail. An empty list returns (no background tasks). Kill returns requested cancellation of task <id> or the existing terminal status. Unreported owned completion uses the notice above.

Token effect

Results and notices remain in parent history until compaction. Stream reads do not repeat consumed output; a producer-supplied outputLimitBytes bounds each complete read or notice.

KV Cache effect

Append-only; newly visible content follows the reusable request prefix and does not invalidate existing KV-cache entries.

Known Limitations and Deferred Work

• Completion notices do not wake idle agents — callers needing an immediate result must use task_output.
• Stream reads are single-consumer — independent observers need another runtime API.
• Unowned tasks have no session fence — external surfaces must supply caller policy or avoid them.