v2.44.0 v2.45.0
pydantic/pydantic-aiSep 17, 2026 → Sep 18, 20261 day between releases
What's New
Introduces TypeSafeModel and optimizes durable run performance
New Features
- Adds TypeSafeModel for TypeSafe's Jev
Improvements
- Optimizes DynamicToolset and MCP sessions to resolve once per durable run
- Removes legacy httpx imports for FastMCP 4 compatibility
Bug Fixes
- Supports xhigh effort and new GPT model variants on Bedrock
- Preserves tool history in MCPSamplingModel
- Fixes usage reporting on spans
Upgrade Notes
No breaking changes detected in this release. Ensure FastMCP 4 compatibility if using legacy httpx imports.
The Two Releases
v2.44.0 (2026-09-16)
Sep 17, 2026· 1 month ago
This release focuses on fixing four security vulnerabilities related to `web_fetch_tool`, `web_fetch`, and OpenTelemetry instrumentation, including fixes for IPv6 bypass and event loop blocking. It introduces new features such as Vercel AI SDK support and a stable serialized shape for `AgentRunResult`, alongside several compatibility updates.
Full release notesv2.45.0 (2026-09-17)
Sep 18, 2026· 1 month ago
This release introduces a new `TypeSafeModel` for TypeSafe's Jev and includes performance optimizations for durable runs. It also fixes compatibility issues with FastMCP 4 by removing legacy `httpx` imports and improves Bedrock support.
Full release notes