Summary

When a sub-agent spawned via sessions_spawn completes in a Telegram forum topic context, the announce step fails to deliver the result back to the requester chat. The system retries 3 times and gives up silently — the parent session never receives the completion notification.

Environment

• OpenClaw: Docker/Zeabur deployment
• Channel: Telegram (forum/supergroup with topics enabled)
• Sub-agent mode: sessions_spawn with mode: "run"

Steps to Reproduce

1. In a Telegram forum topic (not the General topic), spawn a sub-agent:

   sessions_spawn(task="...", label="test", mode="run", model="opus-4.6")
   

2. Note: thread=true fails immediately with "thread=true is unavailable because no channel plugin registered subagent_spawning hooks"
3. Fall back to thread=false — spawn succeeds, sub-agent runs and completes normally
4. Sub-agent finishes (outcome.status: "ok") but the announce never arrives in the forum topic

Evidence from ~/.openclaw/subagents/runs.json

{
  "runId": "<REDACTED_RUN_ID>",
  "requesterSessionKey": "agent:main:telegram:group:<REDACTED_GROUP_ID>:topic:<REDACTED_TOPIC_ID>",
  "requesterOrigin": {
    "channel": "telegram",
    "to": "telegram:<REDACTED_GROUP_ID>",
    "accountId": "default",
    "threadId": <REDACTED_TOPIC_ID>
  },
  "outcome": { "status": "ok" },
  "endedReason": "subagent-complete",
  "announceRetryCount": 3,
  "lastAnnounceRetryAt": <REDACTED_TIMESTAMP>
}

Key observations:

• announceRetryCount: 3 — all 3 retries failed
• requesterOrigin.threadId: <REDACTED_TOPIC_ID> — the target is a forum topic
• The sub-agent itself completed successfully (outcome.status: "ok")
• No error message is surfaced anywhere — the failure is completely silent

Expected Behavior

The announce message should be delivered to the same forum topic where the sub-agent was spawned, preserving the threadId / message_thread_id in the Telegram API call.

Actual Behavior

Announce delivery fails 3 times and is silently dropped. The parent session has no way to know the sub-agent finished unless it manually polls via subagents list.

Additional Context

• thread=true is not supported for Telegram at all ("no channel plugin registered subagent_spawning hooks"), so the only option is thread=false
• Regular (non-forum) Telegram groups may not have this issue — the problem appears specific to forum topics where message_thread_id routing is required
• This forces a workaround where sub-agents must write results to files instead of relying on the announce mechanism

Suggested Fix

The Telegram adapter's announce delivery path should:

1. Preserve threadId from requesterOrigin when posting the announce message
2. Pass message_thread_id to the Telegram Bot API sendMessage call
3. Surface announce delivery failures in logs or as a system message to the parent session (rather than silent drop)