Pydantic AI Updates: September 13, 2026

1. Pydantic AI 2.43.0 Opens clai Sessions With a Run Description Banner

Pydantic AI tagged v2.43.0, a small release whose one new feature is a first-run banner that describes the run, now shown when a clai session opens. Two fixes ship alongside it: OpenAIChatModel was losing text part boundaries after tool calls, and temporal tool opt-out checks were keyed off an MCP import rather than the operation kind, which is the more reliable signal. Source