openclaw - 💡(How to fix) Fix Webchat long-running task completions often don't surface until refresh; embedded agent WS stream falls back with HTTP 500 [1 participants]

Summary

In OpenClaw 2026.3.28, long-running subagent / embedded-agent task completions are successfully persisted server-side, but the webchat UI often does not surface the completion live. Refreshing the webchat immediately causes the completed result to appear, suggesting backend persistence is fine but live event delivery or frontend subscription/reconciliation is broken.

The strongest correlated backend signal is repeated embedded agent websocket stream failures:

• agent/embedded [ws-stream] WebSocket connect failed ... falling back to HTTP
• Error: Unexpected server response: 500

At the same time, webchat disconnect/reconnect events occur, and on reconnect the UI issues chat.history, after which the missing completion becomes visible.

Version / Environment

• OpenClaw version: 2026.3.28
• Commit: f9b1079283a8ee25a7cee77c8f8225d5c813bc30
• Surface: local webchat / control UI
• Gateway mode: local loopback
• Gateway port: 18789

Observed behavior

When launching a long-running task from webchat:

1. task runs successfully
2. backend stores completion
3. webchat often appears stale / “stuck”
4. no live completion appears in the chat window
5. refresh or reconnect causes chat.history
6. completion becomes visible immediately

This creates the impression that the task is still running even though it already finished.

Expected behavior

When a long-running task completes:

• webchat should surface the completion live without requiring a manual refresh
• if WS streaming is degraded, frontend should reconcile automatically through fallback history/session refresh

Key log evidence

Observed repeatedly in gateway logs:

warn agent/embedded [ws-stream] WebSocket connect failed for session=...; falling back to HTTP. error=Error: Unexpected server response: 500

Also observed:

info gateway/ws webchat disconnected code=1001
info gateway/ws webchat connected ...
info gateway/ws ⇄ res ✓ chat.history ...

This pattern matches the user-facing symptom exactly:

• result exists
• live surfacing fails
• refresh/reconnect reloads history and reveals completion

Why this appears to be a live delivery / UI issue rather than task failure

• task completions are successfully persisted
• agent.wait completes successfully
• refresh recovers the “missing” completion
• therefore backend execution is not the primary failure
• the likely failure is:
  • embedded-agent websocket stream path
  • frontend live subscription/reconciliation
  • or both

Likely root cause

Most likely there are two related issues:

1. Embedded agent websocket stream upgrade failure

The embedded agent WS stream appears to be attempting a websocket connection and receiving HTTP 500 instead of a valid upgrade.

2. Webchat fallback / resubscribe weakness

When WS streaming fails or the chat reconnects, the webchat UI does not robustly reconcile long-running task completion state unless a full refresh/reconnect triggers chat.history.

Suggested areas to inspect

Backend

• embedded agent websocket route / upgrade handler
• why the route returns HTTP 500 on stream connect
• whether fallback-to-HTTP mode still emits completion events that webchat is expected to consume

Frontend / control UI

• live stream client for embedded/subagent events
• reconnection behavior after WS degradation
• whether webchat should trigger history/session refresh automatically after:
  • stream failure
  • agent.wait completion
  • reconnect after disconnect

Suggested fixes

Backend

• fix embedded-agent WS stream upgrade path so it does not 500
• improve logging to identify exact route / cause of failure

Frontend

• if stream degrades/fails, automatically reconcile via:
  • session refresh
  • chat history refresh
  • or lightweight polling while a run is active
• improve resubscription after reconnect
• optionally surface a “live updates degraded” banner instead of appearing stuck

Practical workaround

Current workaround:

• refresh/reopen the webchat when a long-running task appears stuck
• completion often appears immediately after chat.history reloads

Repro steps

1. Open local OpenClaw webchat/control UI
2. Launch a long-running subagent or other embedded-agent task
3. Leave the chat open while the task runs
4. Observe task completion may not appear live
5. Refresh the page
6. Observe the completion appears immediately
7. Check gateway logs for:
   • ws-stream ... Unexpected server response: 500
   • webchat disconnect/reconnect
   • chat.history immediately after reconnect