Summary

When a task is delegated via sessions_spawn with runtime="acp", the ACP session has no completion notification mechanism — the requester channel (Discord, WhatsApp, etc.) never receives a push notification when the task finishes. Users have to manually ask for status updates.

Even for runtime="subagent", agents will sometimes promise "I'll ping you when done" but the delivery silently fails if the origin resolution can't establish a clear channel+target at announce time.

Root Cause

In src/agents/tools/sessions-spawn-tool.ts, the spawnAcpDirect path does not pass expectsCompletionMessage: true (unlike spawnSubagentDirect):

// runtime === 'acp'
const result = await spawnAcpDirect({ task, label, agentId, ... });
// ^^^^ no expectsCompletionMessage, no completion announce wired up

// runtime === 'subagent'
const result = await spawnSubagentDirect({
  ...
  expectsCompletionMessage: true,  // subagent gets this
});

Additionally, in src/agents/acp-spawn.ts, the only lifecycle hook called is parentRelay?.notifyStarted() — there is no equivalent notifyCompleted() that feeds back into the announce pipeline.

Reproduction

1. Be in a Discord channel with OpenClaw connected
2. Ask the agent to do a long-running task (e.g. "implement feature X, full test coverage, push to branch")
3. Agent spawns an ACP session (runtime="acp")
4. Task completes ✅ — no message is sent to Discord
5. User has to manually ask "are you done?"

Expected Behavior

When an ACP (or subagent) session completes, the requester channel should automatically receive a push notification with the result — the same way the runtime="subagent" path works when expectsCompletionMessage: true and the announce pipeline successfully resolves the delivery origin.

Proposed Fix

Option A (minimal): Wire up a completion announce for ACP sessions in acp-spawn.ts, similar to how subagent-registry-runtime.ts triggers runSubagentAnnounceFlow when a subagent run ends.

Option B (explicit hook in sessions_spawn): Add an onComplete parameter to sessions_spawn that lets the calling agent (or system prompt) explicitly declare a delivery target:

sessions_spawn({
  task: "...",
  runtime: "acp",
  onComplete: {
    channel: "discord",
    target: "#general",  // or a session key
    message: "optional override message"
  }
})

This would be stored on the run record and fired by the announce pipeline regardless of runtime type.

Option C (agent-side workaround): Document a reliable pattern for agents to self-schedule a completion check (e.g. a cron job that monitors the ACP session and fires a message when it detects completion). This is fragile and puts the burden on the agent.

Option A is the most conservative fix; Option B gives callers explicit control and works for both runtimes.

Environment

• OpenClaw v2026.3.2
• Channel: Discord (ACP thread sessions)
• Also reproducible with WhatsApp as the requester channel

Related

• Issue Agent executes code block contents as shell commands instead of writing to files #39233 (agent executes code block contents as shell commands)