Date: February 13, 2026
Duration: ~3 hours
Severity: High
Status: Resolved
Note: This fix will be available starting from v1.81.13-nightly or 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 flag errors when unsupported headers were present.
- Cost tracking and routing: No impact.