Web plan-mode feature with two lifecycle-coupled halves. The node entry mounts @deepseek-ai/dsh-plan-mode with the Web product policy; the browser entry contributes a session-scoped selector to conversation.composer.controls.

The selector distinguishes unavailable capability (planMode === null), committed mode (active), and the target queued for the next model-request boundary (pending, including pending: false). Selecting a mode never cancels a running turn. It remains available while generation is running, disables only during its own RPC, and displays the host-confirmed pending target until a logged plan/mode event commits it.

The model exits plan mode through the stable exit_plan_mode tool. Its plan review uses the composed Web question channel: approval schedules default mode for the next step, while rejection or custom feedback keeps plan mode active and returns the feedback to the model.

Model Experience

Indirectly, through @deepseek-ai/dsh-plan-mode; that package owns policy activation, the exit-tool schema and rendering, logged state, and request-boundary transitions, while this package supplies the Web composition's section text.

KV Cache effect

Entering or leaving plan mode changes the active system-prompt section and therefore the request prefix. The stable exit-tool registration avoids an additional tool-catalog shape change across the same transition.

Known Limitations and Deferred Work

Plan mode is guidance, not an execution sandbox — deployments that require enforced read-only planning must compose the independent sandbox and approval policies.
The control belongs to the default composer — a pending whole-composer interaction such as plan review temporarily replaces the InputBar and its mode control.
An idle pending target is process-local until the next boundary — a process exit before another prompt loses that uncommitted intent; the committed mode remains durable in the session log.