Incident Report: Invalid beta headers with Claude Code
Date: February 13, 2026 Duration: ~3 hours Severity: High Status: Resolved
Note: This fix will be available starting from
v1.81.13-nightlyor higher of LiteLLM.
Summary​
Claude Code began sending unsupported Anthropic beta headers to non-Anthropic providers (Bedrock, Azure AI, Vertex AI), causing invalid beta flag errors. LiteLLM was forwarding all beta headers without provider-specific validation. Users experienced request failures when routing Claude Code requests through LiteLLM to these providers.
- LLM calls to Anthropic: No impact.
- LLM calls to Bedrock/Azure/Vertex: Failed with
invalid beta flagerrors when unsupported headers were present. - Cost tracking and routing: No impact.


