Pydantic AI v2.55.0 (2026-10-09)

Pydantic AI releases published Pydantic AI v2.55.0 (2026-10-09). This automated release-watch entry was generated from the project's official GitHub release feed and is kept separate from human-reviewed editorial analysis. Release notes: What's Changed ⚠️ Compatibility Notes Require Python 3.11 or newer in every package; Python 3.10 installs resolve to 2.54.0 and earlier by @Kludex in 9526 Record the tool requests of ExaSearch , YouSearch , LocalStack and other harness capabilities under durable execution by @DouweM in 9705 Bound retained realtime audio like retained images with retain audio max seconds by @DouweM in 9702 Prefix LogfireMCP tool names with logfire by @mpfaffenberger in 9868 Serialize FileUrl.media type as null for extensionless URLs instead of raising by @pydanty in 8405 Take realtime history, usage, and reply waits from the session core on OpenAI, Azure OpenAI, and xAI by @DouweM in 9612 Keep default run id and conversation id stable when a durable run is re-executed by @DouweM in 9701 Record each failed FallbackModel attempt with its model, timing, error and usage, and count rejected responses in…

• Review the official Pydantic AI releases release notes before upgrading.
• Check compatibility, migration, and security notes against your current agent stack.
• Run focused regression tests before production rollout.