Summary

When a sub-agent is spawned via sessions_spawn, the gateway's agent handler already receives and resolves to and threadId from the requester session context. However, resolvedTo was never mapped to runContext.currentChannelId, leaving the message tool's zero-param target inference with nothing to fall back on.

Symptom: Sub-agents calling message with action=send and no explicit to, channel, or threadId would fail with Action send requires a target — even though the parent session had a fully-resolved delivery target.

Root Cause

buildThreadingToolContext() (in agent-runner-utils.ts) sets currentChannelId = sessionCtx.To?.trim() for the main session. For sub-agents launched via sessions_spawn, sessionCtx.To is empty because the sub-agent session has no inbound message context — it only has the runContext passed from the gateway handler. resolvedTo was present in that handler but was never forwarded into runContext.currentChannelId.

Fix

One line added to src/gateway/server-methods/agent.ts:

// Before
runContext: {
  messageChannel: resolvedChannel,
  // ...
  currentThreadTs: resolvedThreadId != null ? String(resolvedThreadId) : undefined,
},

// After
runContext: {
  messageChannel: resolvedChannel,
  // ...
  currentThreadTs: resolvedThreadId != null ? String(resolvedThreadId) : undefined,
  currentChannelId: resolvedTo || undefined,
},

This flows through: agentCommand → runEmbeddedPiAgent → createOpenClawCodingTools → createMessageTool → tool context inference in message-action-runner.ts.

Verification

Tested end-to-end on Discord thread sessions:

• Sub-agent spawned with prompt Count to 10. Send each number as a separate message. — no thread info passed
• All 10 messages delivered to the correct Discord thread (channel:1474502983390593189)
• Zero explicit to, channel, or threadId params used by the sub-agent

Explicit routing params still take full precedence when provided. This change only affects the fallback inference path.

Drawbacks / Considerations

• Sub-agents now silently inherit the parent's delivery target. Previously they'd error if to was omitted; now they succeed and send to the parent thread. This is almost always desirable but worth noting as a behavior change for sub-agents intended to run silently.
• Cron/hook-spawned sub-agents will inherit whatever resolvedTo the triggering context resolves to, which may be an unrelated channel. Same mitigation as always: pass an explicit to to override.

AI-Submitted PR

⚠️ This PR was identified, implemented, and submitted by Cognis, an AI agent running on OpenClaw (user: Galygious). It has been manually end-to-end tested as described above but has not been run through the automated test suite. Please review accordingly.

A regression test covering sub-agent message tool target inference (verifying currentChannelId is populated from resolvedTo in the agent handler) would be a valuable addition.