feat(subagent): make final reports the continuable return contract

A continuable child could finish without giving its parent a usable
result: the report tool was described as optional and its default
delivery stayed quiet. Install the child-scoped report obligation (tool
description plus the tool:report prompt section), default reportDelivery
to wakeup, bind shipped subagent_fork delegations to one-shot so fork
keeps its prefix reuse, and extend the ACP snapshot harness to pin child
system prompts alongside child tool schemas.
This commit is contained in:
Hypatia May
2026-08-11 11:50:39 +08:00
parent 6d3cabf295
commit 76cf6cbd0b
79 changed files with 916 additions and 326 deletions
@@ -124,14 +124,12 @@ interface ToolArgsMap {
/** Run as a background subagent that keeps its conversation and return only its subagent id. This call never returns its result; send it more work with send_message. */
run_in_background?: boolean;
} & Record<string, JsonValue>;
/** Delegate a task to a subagent that inherits this conversation: a child agent seeded with all completed turns so far (it does not see the current in-flight turn), returning only its final result. Use this when the subtask builds on this conversation's context — a follow-up analysis, a review, a continuation — without consuming this conversation's context for the work itself. You receive only its final answer, not its intermediate steps. Set `run_in_background: true` to start a background subagent that keeps its conversation: you receive only its subagent id, never its result, and it works on its own. Use this for work whose result you do not need returned by this call; `send_message` sends it more work. */
/** Delegate a task to a subagent that inherits this conversation: a child agent seeded with all completed turns so far (it does not see the current in-flight turn), returning only its final result. Use this when the subtask builds on this conversation's context — a follow-up analysis, a review, a continuation — without consuming this conversation's context for the work itself. You receive only its final answer, not its intermediate steps. */
subagent_fork: {
/** A short (3-5 word) description of the delegated task, for display. */
description: string;
/** The task for the subagent. It already sees this conversation's completed turns, so build on them freely and state only what is new. */
prompt: string;
/** Run as a background subagent that keeps its conversation and return only its subagent id. This call never returns its result; send it more work with send_message. */
run_in_background?: boolean;
} & Record<string, JsonValue>;
/** Request cancellation of a running background task by task id. Returns immediately; the task settles as killed once its work actually stops. */
task_kill: {