Long streamed messages show full text then get truncated to ...(truncated)... after completion

[meager moth]

OpenClaw Version: 2026.4.21 (f788c88)

Bug Description:
When receiving a relatively long reply from the model:

1. During streaming output, the entire content of the message is fully displayed normally on the web chat interface.
2. Immediately after the streaming response is fully completed, the web frontend automatically truncates the latter part of the message.
3. Only the beginning content is retained, followed by ...(truncated)....

Additional Important Observation:
The complete full response message can be viewed normally without any truncation on third-party client integrations such as Telegram and Discord.
This confirms that the backend has received and generated the complete response successfully. The truncation issue exists only on the official web frontend interface.

Expected Behavior
The full message content should remain fully visible on the web UI after streaming completes, and should not be truncated automatically.

[soft night]

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[scenic basin]

I’m checking the web UI path now, since your backend-vs-frontend observation is actually very useful.

Nice, I found the exact code path. This does not look like the model/backend losing content, it looks like WebChat replacing the live stream with a bounded chat.history snapshot after the run finishes.

Yep, this matches a WebChat history cap, not a backend/model loss bug.

What’s happening:

• during streaming, the web UI shows the live full stream
• after completion, it refreshes from chat.history
• chat.history intentionally truncates long text fields and appends exactly ...(truncated)...

That also explains why Telegram/Discord still show the full message.

Try bumping this:

openclaw config set gateway.webchat.chatHistoryMaxChars 50000
openclaw gateway restart

Docs:

• https://docs.openclaw.ai/web/webchat
• https://docs.openclaw.ai/gateway/configuration

So, short version: this is a WebChat/UI history limit issue. If raising gateway.webchat.chatHistoryMaxChars does not fix it, then I’d file it as a bug here: https://github.com/openclaw/openclaw/issues

If you want, I can help you pick a sane value for that limit.

[meager moth]

using openclaw config set gateway.webchat.chatHistoryMaxChars 50000 fixed,thank you @scenic basin