Summary

In group/channel contexts, background ACP/subagent completions can surface only a generic lifecycle message such as:

• Background task done: ...
• Background task failed: ...
• Background task timed out: ...

without a real follow-up reply from the parent agent explaining the actual result.

This leaves the user with completion telemetry but not the conversational answer they were waiting for.

Why this is a problem

For background/delegated work in group channels, the desirable flow is:

1. child/background task stays internal
2. parent conversation receives completion context
3. parent agent sends the user-facing summary

Instead, the current behavior can stop after step 1 with only a raw completion marker visible in the channel.

Reproduction

1. Start a conversation in a group/channel context.
2. Ask the agent to delegate a meaningful task through a background ACP or subagent run.
3. Wait for the delegated task to complete.
4. Observe the visible channel output.

Actual behavior

The channel receives only a generic lifecycle line such as:

Background task done: <task summary>

or similar failed/timed out variants, with no real user-facing completion summary from the parent agent.

Expected behavior

When the background task completes:

• the child/background output should remain internal
• the parent session should receive the completion event/context
• the parent agent should send the actual user-facing summary

If a lifecycle marker is retained at all, it should be secondary telemetry rather than the only visible response.

Likely code area

The behavior appears related to the terminal task delivery path in src/tasks/task-registry.ts, where direct generic completion delivery to the requester origin can bypass a proper parent-agent conversational handoff.

Related context

Possibly adjacent to earlier UX issues around delegated/background output in group rooms, but this issue is specifically about the missing parent-agent completion summary rather than about adding config toggles.