Anthropic SDK Returns status_code=200 for Mid-Stream SSE Errors

What this error means

Anthropic APIStatusError with status_code=200 for mid-stream SSE overloaded_error is a Anthropic API failure pattern reported for developers trying to fix anthropic python sdk returning wrong status code 200 for streaming sse errors like overloaded_error. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Filed 2026-03-18, closed. Bug in _streaming.py passing original HTTP response (status 200) to _make_status_error instead of the SSE error’s actual status code. Affects all streaming users relying on error classification.

Common causes

• When the Anthropic API streams fine initially but then sends an SSE error event (like overloaded_error/529), the SDK creates APIStatusError with status_code=200 instead of the actual error code. This breaks retry logic, error handling, and monitoring that rely on status codes.
• Filed 2026-03-18, closed. Bug in _streaming.py passing original HTTP response (status 200) to _make_status_error instead of the SSE error’s actual status code. Affects all streaming users relying on error classification.

Quick fixes

1. Confirm the exact error signature matches Anthropic APIStatusError with status_code=200 for mid-stream SSE overloaded_error.
2. Check the Anthropic API 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/anthropic-sdk-python/issues/1258

Evidence note: Filed 2026-03-18, closed. Bug in _streaming.py passing original HTTP response (status 200) to _make_status_error instead of the SSE error’s actual status code. Affects all streaming users relying on error classification.

Related errors

• Anthropic SDK streaming error wrong status code
• Anthropic APIStatusError status_code=200 overloaded_error
• Anthropic SDK SSE error handling bug

FAQ

What should I check first?

Start with the exact Anthropic APIStatusError with status_code=200 for mid-stream SSE overloaded_error text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Anthropic API 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 Anthropic APIStatusError with status_code=200 for mid-stream SSE overloaded_error.