Anthropic API / Anthropic API
Anthropic API strict: true Causes 500 Internal Server Error with Complex Tool Schemas
Fix Anthropic API 500 Internal Server Error when using strict: true with complex nested tool schemas Includes evidence for Anthropic API troubleshooting demand.
- Category
- Anthropic API
- Error signature
500 Internal Server Error- Quick fix
- Compare the failing environment with a known working setup, then change one configuration value at a time.
- Updated
What this error means
500 Internal Server Error is a Anthropic API failure pattern reported for developers trying to fix anthropic api 500 internal server error when using strict: true with complex nested tool schemas. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
GitHub issue #885 in anthropics/anthropic-sdk-typescript. Direct 500 error from Anthropic API when combining strict mode with complex nested tool schemas in structured outputs.
Common causes
- Using strict: true with Anthropic’s structured outputs beta (structured-outputs-2025-11-13) returns a 500 Internal Server Error when tool schemas contain complex nested objects. Developers using structured outputs with Claude need a workaround.
- GitHub issue #885 in anthropics/anthropic-sdk-typescript. Direct 500 error from Anthropic API when combining strict mode with complex nested tool schemas in structured outputs.
Quick fixes
- Confirm the exact error signature matches
500 Internal Server Error. - Check the Anthropic API account, local tool state, and provider configuration involved in the failing workflow.
- 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
- 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: GitHub issue #885 in anthropics/anthropic-sdk-typescript. Direct 500 error from Anthropic API when combining strict mode with complex nested tool schemas in structured outputs.
Related errors
- Anthropic structured outputs error
- Claude API tool use schema error
- Anthropic API 500 error
FAQ
What should I check first?
Start with the exact 500 Internal Server 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 500 Internal Server Error.