Pydantic AI v2.54.0 (2026-10-02)

Pydantic AI releases published Pydantic AI v2.54.0 (2026-10-02). 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 Handle draft-7 list-form items in JsonSchemaTransformer , TestModel and Mistral streamed output, and make TestModel accept boolean subschemas and cap prefixItems at maxItems by @dsfaccini in 9560 Fix ImageGeneration under FallbackModel and dataclasses.replace , and compare Embedder by identity by @dsfaccini in 9477 Refuse a second durable execution engine on an agent before either binds by @DouweM in 9391 Make wrap hooks enclose complete stage lifecycles by @adtyavrdhn in 7053 Re-raise model errors from Temporal model activities with their original type in workflow code by @DouweM in 9580 End the run when a BackgroundTools tool raises an unexpected exception, as a sequential tool does by @DouweM in 9434 Drop the SubAgents agent folders default-change warning: since v2.52.0 ( 9023 ) the agents folder is not loaded by default, so pass agent…

• 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.