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Pydantic AI Updates: May 27, 2026

pydantic-ai release mcp openrouter bedrock

1. Pydantic AI v1.103.0 adds MCP prompt support, OpenRouter eager streaming, and adaptive thinking detection

Pydantic AI. Pydantic AI shipped v1.103.0 with several MCP and model-integration improvements. The release adds list_prompts and get_prompt methods to McpServer, round-trips message timestamps through VercelAIAdapter’s UIMessage.metadata, and exposes an anthropic_eager_input_streaming parameter on the OpenRouter model. Bug fixes map Bedrock malformed_model_output and malformed_tool_use errors to FinishReason.error, recognize type='adaptive' thinking, strip force_download from client-submitted FileUrl parts in the UI adapter’s sanitize_messages, and warn when toolset prepare callbacks return None. Source