pydantic/pydantic-ai v2.53.0: v2.53.0 (2026-10-01)

Key points

• <!-- Release notes generated using configuration in .github/release.yml at main -->1
• Repeated streams could then block every request sharing the limiter.1
• Agent-level maxconcurrency and non-streaming requests are not affected.1
• The fix also changes how limiters are shared: a model wrapper now raises UserError when it shares a limiter with the agent making the request or with an enclosing model wrapper, ConcurrencyLimiter.acquire() takes a slot on every call, even on the same task, and a custom AbstractConcurrencyLimiter must allow release() from another task.1

Sources (1)

• [1]pydantic/pydantic-ai v2.53.0: v2.53.0 (2026-10-01)
  GitHub: pydantic/pydantic-ai · Oct 2, 02:52 AM

  This release fixes one security issue in `ConcurrencyLimitedModel`.

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

Extractive summary: sentences quoted from the sources.