openclaw - 💡(How to fix) Fix [Bug]: WebChat duplicate/collapsed messages after tool calls [3 comments, 3 participants]

Description

Messages in the WebChat UI occasionally appear duplicated — both user messages and assistant responses are shown twice consecutively. The issue is intermittent (flaky). It tends to reappear after several tool invocations (especially exec). Restarting the Gateway temporarily resolves it until the next round of tool calls.

Sometimes the duplication manifests as a merge/collapse of two consecutive assistant replies into one garbled block, as if a race condition in websocket delivery combines them.

Steps to reproduce

1. Start a fresh WebChat session (Gateway restarted).
2. Exchange a few messages — everything looks normal.
3. Invoke a tool command (e.g., exec, write + reply in the same turn).
4. Observe: the user or assistant messages now appear twice in the chat.
5. Refreshing the page may temporarily clear it, but it returns after more tool calls.

Expected behavior

Each user message and each assistant reply should appear exactly once, in correct order, without duplication or merging.

Environment

• OpenClaw version: 2026.4.26 (be8c246)
• Installed via: npm (global)
• WebChat channel only (not tested on other channels)
• Model: deepseek/deepseek-chat (but likely unrelated — issue is in the webchat routing layer)
• Host: WSL2 (Ubuntu), Node v24.15.0

Additional notes

• First observed on 2026-04-16, returned after 2026-04-26 update.
• Seems exacerbated when multiple side-effects (exec, file write, text reply) happen within a single assistant turn.
• Not reliably reproducible on every tool call — flaky by nature.
• No error logs visible client-side.