Run Claude 4.6+ reliably across Anthropic, Bedrock, Vertex AI, and LiteLLM

Claude 4.6 and later models do not support assistant message prefill, which previously caused silent failures or malformed requests when conversations ended with an assistant turn. Agno now automatically injects a trailing user message in these cases, with centralized detection logic shared across all Claude deployment paths, including Anthropic, AWS Bedrock, Vertex AI, and LiteLLM, so the fix applies consistently regardless of how Claude is served.

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Details:

Trailing user message injection is applied automatically when the last message in a conversation is an assistant message and the model does not support prefill
Prefill support detection is centralized and version-aware, covering Claude 4.6+ across Anthropic, Bedrock, Vertex AI, and LiteLLM providers
No configuration changes required; existing agents and teams using Claude are unaffected

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