fix: make agent_end auto-capture hook non-blocking (fire-and-forget)

[qingshuicn]

Problem

The agent_end hook for auto-capture (index.ts:2191) is async and awaits multiple slow operations:

• smartExtractor.filterNoiseByEmbedding() — embedding API call
• smartExtractor.extractAndPersist() — LLM call (6-category extraction + dedup)
• embedder.embedPassage() — embedding for regex fallback
• store.vectorSearch() — vector similarity search for dedup

When OpenClaw's hook system awaits the returned promise, it holds the session lock for the entire duration of these API calls (potentially 30+ seconds with default LLM timeout). This causes downstream channel deliveries (particularly Telegram) to be silently dropped when subsequent messages hit session store lock timeouts.

Symptoms

• First message in a Telegram session gets a response
• All subsequent messages are received and processed (tools.profile loads, memory plugin runs) but sendMessage never fires
• No errors logged anywhere — completely silent failure
• Disabling autoCapture and smartExtraction immediately resolves the issue

Fix

Wrap the async capture work inside the agent_end handler in a void IIFE so the hook returns immediately. The capture work continues in the background without blocking the session.

// Before: blocks session until all API calls complete
api.on("agent_end", async (event, ctx) => {
  // ... slow embedding/LLM/vector calls ...
});

// After: returns immediately, work runs in background
api.on("agent_end", (event, ctx) => {
  void (async () => {
    // ... same work, but non-blocking ...
  })();
});

Change: 8 lines added, 1 line modified. The early-return guard (!event.success) stays synchronous for efficiency.

Testing

Verified on OpenClaw v2026.3.13 with Telegram channel (long-polling, streaming: "partial"):

• Before fix: Bot responds to first message only; all follow-ups silently dropped
• After disabling autoCapture/smartExtraction: All messages get responses (confirmed workaround)
• Fix approach: Same behavioral result as the workaround, but with auto-capture still active

Related

• Fixes autoCapture + smartExtraction agent_end hook causes Telegram messages to be silently dropped #260
• Related to [Bug] autoRecall in before_agent_start can stall agent startup / Control UI when retrieval is unhealthy #253 (autoRecall stalling agent startup — same pattern, different hook)