Bug Description

When spawning a subagent using sessions_spawn, the documentation states it will "auto-announces on completion", but the completion notification is never sent to the requester session.

Expected Behavior

According to the tool response:

{
  "note": "auto-announces on completion, do not poll/sleep. The response will be sent back as an user message."
}

When a subagent completes its task, a notification should be automatically sent to the requester session.

Actual Behavior

• Subagent completes successfully
• No notification is sent to the requester session (neither in group chats nor in DMs)
• User must manually ask or check subagents list to discover completion

Steps to Reproduce

1. In a Telegram group chat, use sessions_spawn to start a subagent
2. Wait for the subagent to complete
3. Observe: no completion notification is received

Test Cases

Case 1: Memory Sync System Implementation

• Subagent: opus1
• Label: memory-sync-system-impl
• Runtime: 6 minutes
• Result: Completed successfully, but NO notification sent

Case 2: Memory Sync System Testing

• Subagent: sonnet1
• Label: memory-sync-test
• Runtime: 2 minutes
• Result: Completed successfully, but NO notification sent

Environment

• OpenClaw version: 2026.2.19-2
• OS: macOS Darwin 24.6.0 (arm64)
• Channel: Telegram
• Session type: Group chat (forum topic)

Impact

High - This breaks the entire subagent workflow. Users have no way to know when tasks complete without constantly polling, defeating the purpose of async task delegation.

Workaround

Currently using manual polling with subagents list, but this is inefficient and user-unfriendly.

Additional Context

• Verified notification is missing in both group chats AND private messages
• subagents list correctly shows status as "done"
• Problem affects all subagent spawns, not just specific tasks