Pydantic AI v2.47.0 (2026-09-21)
Pydantic AI v2.47.0 brings compatibility changes around UserPromptPart validation and None route naming, improves TypeSafeModel routing and field handling, and fixes several edge-case crashes.
Why this signal matters
Pydantic AI released version v2.47.0 on 2026-09-21. Key compatibility changes include renaming None output routes from NoneType to None, and raising an error when UserPromptPart.content is neither a string nor a sequence (preventing silent transmission of dictionary keys). Features and bug fixes center around TypeSafeModel enhancements, such as supporting three additional field types, handling None routes/options with descriptions, supporting Choices sets as routes, and preventing crashes when encountering tuple output fields with self-contained models or oversized rubric levels. The ag-ui-protocol dependency has also been pinned to <1.
Actionable summary
Pydantic AI release v2.47.0 introduces breaking/compatibility changes (strict type checking on UserPromptPart.content and renaming NoneType routes to None), enhances TypeSafeModel field and route handling, and caps ag-ui-protocol to <1.
- Agent usefulness
- 82/100
- Confidence
- 96%
- Canonical data
- JSON + Markdown
What builders should check
- Verify UserPromptPart.content inputs: ensure passed values are strictly a str or sequence to avoid newly raised exceptions instead of dict keys being silently sent.
- Update any routing logic expecting the route name 'NoneType' to use 'None' instead.
- Ensure environment dependencies accommodate ag-ui-protocol pinned to <1.