Anthropic API / Anthropic API
Anthropic SDK Bedrock streaming crashes on rate limit error with AttributeError
Producers using AsyncAnthropicBedrock cross-region inference profiles intermittently crash on first streaming event when Bedrock returns rate limit error as an SSE event stream; accessing event.message.model raises AttributeError. Includes evidence for Anthropic API troubleshooting demand.
- Category
- Anthropic API
- Error signature
AttributeError: 'NoneType' object has no attribute 'model' — first SSE frame is type=error rate_limit_error, but SDK yields BetaRawMessageStartEvent with message=None- Quick fix
- Reduce request pressure, check quota or plan limits, and retry with backoff instead of immediate repeated requests.
- Updated
What this error means
AttributeError: 'NoneType' object has no attribute 'model' — first SSE frame is type=error rate_limit_error, but SDK yields BetaRawMessageStartEvent with message=None is a Anthropic API failure pattern reported for developers trying to producers using asyncanthropicbedrock cross-region inference profiles intermittently crash on first streaming event when bedrock returns rate limit error as an sse event stream; accessing event.message.model raises attributeerror.. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
Source: anthropics/anthropic-sdk-python#1472 (opened Apr 29, 2026, eu-west-1). Reproduced with global.anthropic.claude-opus-4-7 endpoint. Bedrock returns HTTP 200 with error SSE frame; SDK decodes it but hands caller a BetaRawMessageStartEvent whose message field is None. Multiple PRs linked (#1475, #1479, #1572) indicating ongoing work. Category: Anthropic API — Bedrock integration, rate limit error handling.
Common causes
- Source: anthropics/anthropic-sdk-python#1472 (opened Apr 29, 2026, eu-west-1). Reproduced with global.anthropic.claude-opus-4-7 endpoint. Bedrock returns HTTP 200 with error SSE frame; SDK decodes it but hands caller a BetaRawMessageStartEvent whose message field is None. Multiple PRs linked (#1475, #1479, #1572) indicating ongoing work. Category: Anthropic API — Bedrock integration, rate limit error handling.
Quick fixes
- Confirm the exact error signature matches
AttributeError: 'NoneType' object has no attribute 'model' — first SSE frame is type=error rate_limit_error, but SDK yields BetaRawMessageStartEvent with message=None. - Check the Anthropic API account, local tool state, and provider configuration involved in the failing workflow.
- Reduce request pressure, check quota or plan limits, and retry with backoff instead of immediate repeated requests.
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
- Capture the exact error message and the command, editor action, or request that triggered it.
- Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
- Review the source evidence below and compare it with your environment.
- Apply one change at a time and rerun the smallest failing action.
- 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
Evidence note: Source: anthropics/anthropic-sdk-python#1472 (opened Apr 29, 2026, eu-west-1). Reproduced with global.anthropic.claude-opus-4-7 endpoint. Bedrock returns HTTP 200 with error SSE frame; SDK decodes it but hands caller a BetaRawMessageStartEvent whose message field is None. Multiple PRs linked (#1475, #1479, #1572) indicating ongoing work. Category: Anthropic API — Bedrock integration, rate limit error handling.
Related errors
- Anthropic API
FAQ
What should I check first?
Start with the exact AttributeError: 'NoneType' object has no attribute 'model' — first SSE frame is type=error rate_limit_error, but SDK yields BetaRawMessageStartEvent with message=None 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 AttributeError: 'NoneType' object has no attribute 'model' — first SSE frame is type=error rate_limit_error, but SDK yields BetaRawMessageStartEvent with message=None.