Pydantic AI Updates: April 18, 2026

1. PydanticAI v1.84.1 Fixes Tool Hook Handling for Internal Output Tools

Pydantic AI. The patch release skips tool hooks for internal output tools and ensures validated arguments are correctly passed to hooks when a single-BaseModel tool is invoked. The fix closes a gap introduced in 1.84.0’s Claude Opus 4.7 support and stateful compaction work, and is a drop-in upgrade for anyone relying on custom pre- or post-tool hooks in agent graphs. Source