pydantic-ai 2.50.0

v2.50.0 (2026-09-24)

on Python PyPI

What's Changed

⚠️ Compatibility Notes

• Ask a DecisionModel which route to take by name, with one label per route by @DouweM in #8733
• Make ModelSelectionContext.messages end with the request being routed, and add ModelSelectionContext.prompt by @DouweM in #8737
• Replace the decision model's tool-call lean with an opt-in decision_route_threshold by @DouweM in #8739

🚀 Features

• Expose OpenAI service_tier in provider details by @pydanty in #7945
• Add DecisionModel, a base for Decisions-protocol models, and make TypeSafeModel one by @DouweM in #8696
• Add RunContext.in_durable_context so hooks can tell they run in durable workflow code by @mpfaffenberger in #8723
• Add gemini-3.8-live and gemini-3.8-live-extended-thinking realtime support by @DouweM in #8393
• Ask a DecisionModel's route fields with the route question under a route premise, with nested-field context and a done state after tool calls by @DouweM in #8749
• Emit a decide span for every request a DecisionModel sends by @DouweM in #8698

🐛 Bug Fixes

• Keep the type variable of a generic OutputSpec[T] passed to Agent.run under mypy by @DouweM in #8730
• Send ThinkingParts in the history decision models judge by @DouweM in #8738
• Price Anthropic one-hour cache writes at the one-hour rate instead of the five-minute rate by @kazmer97 in #8666
• Price realtime image input at the image rate by @DouweM in #8741
• Add RequestUsage.audio_seconds so duration-billed voice models are priced by @DouweM in #8427
• Offer a decision model's unfillable output_type as a route beside other routes, and rename ToolCallProposed to UnfillableRoute under a DecisionHandOff base by @DouweM in #8744
• Keep realtime user turns whole when the microphone streams continuously on providers without input item IDs by @DouweM in #8746
• Roll back a realtime send the provider refuses, so wait_for_reply() no longer hangs on it by @DouweM in #8747
• Turn reasoning off for thinking=False on OpenAI Realtime by sending reasoning.effort: 'none' by @DouweM in #8753
• Take Jev's context_window from genai-prices and document compacting a Jev conversation by @DouweM in #8740
• Buffer five minutes of audio per stream_audio() view so speaker-paced playback gets whole replies by @DouweM in #8750
• Stop Google Search from crashing Gemini 2.5 native-audio realtime sessions by @DouweM in #8751
• Keep user speech out of Gemini 3.x realtime history when input transcription is off by @DouweM in #8754
• Surface a failed OpenAI realtime response's error as a RealtimeSessionErrorEvent by @DouweM in #8752

Full Changelog: v2.49.0...v2.50.0