Claude Code VSCode Extension Stream Stall — SSE Dies After tool_use, UI Hangs, Work Silently Lost

What this error means

v2.1.141 regression: VSCode stream stalls at ~670 bytes after tool_use; UI hangs in thinking 5 min, work silently lost is a Claude Code failure pattern reported for developers trying to fix claude code vscode stream stalling after tool_use block, ui stuck in thinking state. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

SSE stream sends ~650-700 bytes (tool_use block dispatched), then goes silent. Files modified server-side but assistant output lost. 5-minute idle timeout. Regression in v2.1.141.

Common causes

• After upgrading Claude Code VSCode extension to v2.1.141, streaming responses die mid-turn at ~650-700 bytes. SSE stream stalls, webview shows ‘thinking’ for 5 minutes until timeout. Server-side tool_use already modified files on disk, but work is silently lost. Data loss regression in paid tool.
• SSE stream sends ~650-700 bytes (tool_use block dispatched), then goes silent. Files modified server-side but assistant output lost. 5-minute idle timeout. Regression in v2.1.141.

Quick fixes

1. Confirm the exact error signature matches v2.1.141 regression: VSCode stream stalls at ~670 bytes after tool_use; UI hangs in thinking 5 min, work silently lost.
2. Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/anthropics/claude-code/issues/58916

Evidence note: SSE stream sends ~650-700 bytes (tool_use block dispatched), then goes silent. Files modified server-side but assistant output lost. 5-minute idle timeout. Regression in v2.1.141.

Related errors

• Claude Code VSCode extension crash
• Claude Code stream timeout
• Claude Code tool execution silent failure

FAQ

What should I check first?

Start with the exact v2.1.141 regression: VSCode stream stalls at ~670 bytes after tool_use; UI hangs in thinking 5 min, work silently lost text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Claude Code workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without v2.1.141 regression: VSCode stream stalls at ~670 bytes after tool_use; UI hangs in thinking 5 min, work silently lost.