v2.33.0

pydantic/pydantic-aiv2.33.0Aug 21, 2026by dsfaccini

AI Summary

This release addresses compatibility issues caused by the `anthropic` library upgrading to version 1.0.0, which removed support for legacy `httpx`. It updates dependencies to support the new SDK and modifies the `AnthropicProvider` to require `httpx2.AsyncClient` for custom clients.

Key Highlights

Support for `anthropic>=1.0.0` and `httpx2`
Requires `httpx2.AsyncClient` for custom Anthropic clients
Fixes runtime failures with Anthropic models

Breaking Changes

AnthropicProvider now requires `httpx2.AsyncClient` instead of legacy `httpx` clients

Full Release Notes

<!-- Release notes generated using configuration in .github/release.yml at main -->

## ⚠️ If Anthropic stopped working for you in the last day

`anthropic` 1.0.0 — rebuilt on `httpx2`, with legacy `httpx` support removed — reached PyPI on August 20. Every earlier pydantic-ai release, including v2.32.2 cut a few hours before this one, allowed that version without supporting it: a fresh or unpinned install of `pydantic-ai[anthropic]` could resolve `anthropic` 1.0.0 and then fail at runtime when using an Anthropic model. Apologies for the breakage window.

- **Fix**: upgrade to `pydantic-ai` v2.33.0, which requires and supports `anthropic>=1.0.0`.
- **If you need to stay on an older pydantic-ai**: pin `anthropic<1`.

If you pass your own `http_client` to `AnthropicProvider`, it must now be an `httpx2.AsyncClient` — the 1.x SDK rejects legacy `httpx` clients at construction.

## What's Changed
### ⚠️ Compatibility Notes
* Use `httpx2` for Anthropic clients by @dsfaccini in https://github.com/pydantic/pydantic-ai/pull/7657


**Full Changelog**: https://github.com/pydantic/pydantic-ai/compare/v2.32.2...v2.33.0