fix(gateway): persist streamed text when webchat final event lacks message by Sid-Qin · Pull Request #31920 · openclaw/openclaw

Sid-Qin · 2026-03-02T16:48:00Z

Summary

Problem: In the webchat interface, when an agent streams text then immediately runs tool calls, the streamed content is lost — the "final" event arrives with `message: undefined` (buffer consumed by sub-run), and the client clears `chatStream` without saving it.
Why it matters: Users see a thoughtful multi-paragraph response streaming in, start reading it, then it vanishes and gets replaced. This is the most-reported UX frustration in webchat.
What changed: Before clearing `chatStream` on a "final" event, check if the stream buffer has non-empty content. If no `finalMessage` was provided, synthesize an assistant message from the buffered text — mirroring the existing "aborted" handler's preservation logic.
What did NOT change: Server-side streaming, the "final" event emission, or the behavior when a proper `finalMessage` is present.

Change Type (select all)

Scope (select all touched areas)

Linked Issue/PR

Closes Bug: Webchat streaming responses get replaced/overwritten by subsequent tool calls #31895

User-visible / Behavior Changes

Streamed text responses in webchat are no longer lost when tool calls follow immediately.
The streamed content is persisted as a chat message before the stream state is cleared.

Security Impact (required)

New permissions/capabilities? `No`
Secrets/tokens handling changed? `No`
New/changed network calls? `No`
Command/tool execution surface changed? `No`
Data access scope changed? `No`

Repro + Verification

Environment

OS: Any
Runtime: Node.js + Browser
Integration/channel: Webchat

Steps

Open webchat session.
Ask a question that triggers text response followed by tool calls (e.g. "explain X and then search for Y").
Agent streams a text response, then immediately calls tools.

Expected

Streamed text persists in chat; tool results appear below.

Actual

Before fix: Streamed text vanishes, replaced by post-tool-call response.
After fix: Streamed text is saved as a message before clearing the stream.

Evidence

Client-side change follows the same pattern as the existing "aborted" handler which already persists streamed text. Added 4 tests: persist on missing finalMessage, skip empty/whitespace streams, skip null stream, prefer finalMessage over stream.

Human Verification (required)

Verified scenarios: text → tool call → final with no message, text → final with message, abort with stream
Edge cases checked: empty stream, whitespace-only stream, null stream, finalMessage takes priority
What I did not verify: Multiple sequential tool calls within a single turn, sub-agent streaming

Compatibility / Migration

Backward compatible? `Yes`
Config/env changes? `No`
Migration needed? `No`

Failure Recovery (if this breaks)

How to disable/revert: Revert the `else if` block in the "final" handler
Files/config to restore: `ui/src/ui/controllers/chat.ts`
Known bad symptoms: If broken, duplicate messages could appear (both stream text and final message)

Risks and Mitigations

Risk: Duplicate messages when both stream and finalMessage exist — Mitigated: `else if` ensures only one path executes
Risk: Empty/whitespace stream persisted — Mitigated: guard checks `state.chatStream?.trim()`

greptile-apps · 2026-03-02T16:52:33Z

Greptile Summary

Added client-side stream persistence logic to prevent loss of streamed text in webchat when tool calls follow immediately. The change mirrors the existing "aborted" handler's pattern.

Key Changes:

Modified chat.ts final event handler to persist chatStream content when finalMessage is undefined
Guard condition (state.chatStream?.trim()) prevents persisting empty/whitespace-only streams
Uses else if to ensure finalMessage always takes precedence, preventing duplicates
Added 4 comprehensive tests covering main use case and edge cases (empty, whitespace, null, precedence)
Updated vitest.config.ts to include the test file

Code Quality:

Follows existing pattern from "aborted" handler (lines 267-286)
Minimal, focused change addressing the reported UX issue
Good test coverage with edge case handling
Backward compatible, purely additive behavior

Confidence Score: 5/5

This PR is safe to merge with minimal risk
The change is well-implemented with comprehensive test coverage, follows existing patterns in the codebase, and addresses a legitimate UX issue. The else if structure prevents duplicate messages, the trim check handles edge cases properly, and the logic mirrors the battle-tested "aborted" handler. All tests pass and cover main use case plus edge cases.
No files require special attention

_{Last reviewed commit: 52cd5cc}

…ssage When an agent streams text and then immediately runs tool calls, the webchat UI drops the streamed content: the "final" event arrives with message: undefined (buffer consumed by sub-run), and the client clears chatStream without saving it to chatMessages. Before clearing chatStream on a "final" event, check whether the stream buffer has content. If no finalMessage was provided but the stream is non-empty, synthesize an assistant message from the buffered text — mirroring the existing "aborted" handler's preservation logic. Closes openclaw#31895

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steipete · 2026-03-02T19:54:33Z

Landed via temp rebase onto main.

Gate: pnpm -s vitest run ui/src/ui/controllers/chat.test.ts
Land commit: a708323
Merge commit: a351ab2

Thanks @Sid-Qin!

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chatgpt-codex-connector · 2026-03-02T19:57:34Z

ui/src/ui/controllers/chat.ts

+    } else if (state.chatStream?.trim()) {
+      state.chatMessages = [


Prevent synthesized stream message from being overwritten

When a final chat event arrives without payload.message, this new branch appends state.chatStream locally, but handleChatEvent still returns "final", so ui/src/ui/app-gateway.ts immediately calls loadChatHistory because shouldReloadHistoryForFinalEvent returns true for missing messages; loadChatHistory replaces chatMessages wholesale, which drops the synthesized assistant message in the same text-then-tool-turn scenario this fix is targeting. Either skip that reload when we synthesize from chatStream, or persist/merge in a way that survives the reload.

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openclaw-barnacle bot added app: web-ui App: web-ui size: S experienced-contributor labels Mar 2, 2026

SidQin-cyber and others added 2 commits March 2, 2026 19:54

fix: persist webchat stream-only finals (openclaw#31920) (thanks @Sid…

a708323

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steipete force-pushed the fix/31895-webchat-streaming-persist branch from 52cd5cc to a708323 Compare March 2, 2026 19:54

steipete merged commit a351ab2 into openclaw:main Mar 2, 2026
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execute008 pushed a commit to execute008/openclaw that referenced this pull request Mar 2, 2026

fix: persist webchat stream-only finals (openclaw#31920) (thanks @Sid…

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github-actions bot mentioned this pull request Mar 2, 2026

📡 Upstream Digest — 2026-03-02 20:27 UTC curtismercier/openclaw-mods#166

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dawi369 pushed a commit to dawi369/davis that referenced this pull request Mar 3, 2026

fix: persist webchat stream-only finals (openclaw#31920) (thanks @Sid…

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OWALabuy pushed a commit to kcinzgg/openclaw that referenced this pull request Mar 4, 2026

fix: persist webchat stream-only finals (openclaw#31920) (thanks @Sid…

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zooqueen pushed a commit to hanzoai/bot that referenced this pull request Mar 6, 2026

fix: persist webchat stream-only finals (openclaw#31920) (thanks @Sid…

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fix(gateway): persist streamed text when webchat final event lacks message#31920

fix(gateway): persist streamed text when webchat final event lacks message#31920
steipete merged 2 commits intoopenclaw:mainfrom
Sid-Qin:fix/31895-webchat-streaming-persist

Sid-Qin commented Mar 2, 2026 •

edited

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		} else if (state.chatStream?.trim()) {
		state.chatMessages = [

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Sid-Qin commented Mar 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Change Type (select all)

Scope (select all touched areas)

Linked Issue/PR

User-visible / Behavior Changes

Security Impact (required)

Repro + Verification

Environment

Steps

Expected

Actual

Evidence

Human Verification (required)

Compatibility / Migration

Failure Recovery (if this breaks)

Risks and Mitigations

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greptile-apps bot commented Mar 2, 2026

Greptile Summary

Confidence Score: 5/5

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Sid-Qin commented Mar 2, 2026 •

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