Add anthropic speed, `fast` mode for opus 4.6 by bohdanhr · Pull Request #4300 · pydantic/pydantic-ai

bohdanhr · 2026-02-11T15:55:26Z

Closes Enable fast mode with anthropic opus 4.6 #4298
Add the anthropic speed added in the new 0.79 release anthropics/anthropic-sdk-python@5953ba7

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Any AI generated code has been reviewed line-by-line by the human PR author, who stands by it.
No breaking changes in accordance with the version policy.
Linting and type checking pass per make format and make typecheck.
PR title is fit for the release changelog.

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New tests for any fix or new behavior, maintaining 100% coverage.
Updated documentation for new features and behaviors, including docstrings for API docs.

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dsfaccini · 2026-04-17T21:53:30Z

this is green now but the tests need to be made VCR

bohdanhr · 2026-04-21T13:27:21Z

@dsfaccini im consistently getting 429 throttled trying to make calls to anthropic with fast mode, would you be able to try?

dsfaccini · 2026-04-21T16:28:18Z

hey @bohdanhr I've actually been blocked for a couple days bc my personal org has no access to fast mode (waitlisted), I'm trying to use it through our gateway to see if that works

bohdanhr · 2026-04-21T17:04:26Z

@dsfaccini same here, we are not waitlisted either.

…gnore - Revert task budget changes merged in from another feature; they belong in pydantic#5140 - Restrict fast-mode support to Claude Opus 4.6 only (per Anthropic docs) - Silently ignore `anthropic_speed` on unsupported models (no UserWarning), per DouweM's review and models/AGENTS.md convention - OMIT `speed` on unsupported models regardless of value (not just for 'fast') - Document prompt-cache invalidation when switching speeds, and that fast mode is not available on Bedrock/Vertex - Fix docs example to use claude-opus-4-6 - Remove stale untracked cassettes from failed real-API recording attempts

Fast mode is only available on the direct Anthropic API. Even when the model supports it (Opus 4.6), sending `speed` via Bedrock, Vertex, or Foundry clients would likely error at the provider gateway. Add `_FAST_MODE_UNSUPPORTED_CLIENTS` and check client type in `_effective_speed` and the fast-mode beta gate.

The `_FAST_MODE_UNSUPPORTED_CLIENTS` tuple already blocks fast mode on Foundry clients, but the user-facing docstring and docs admonition only listed Bedrock and Vertex. Update both so Foundry users know `anthropic_speed` is silently omitted on their client too.

dsfaccini · 2026-04-23T22:21:44Z

+    from unittest.mock import AsyncMock, MagicMock
+
+    import anthropic


move these up top please

- _effective_speed emits UserWarning when 'fast' is set on an unsupported model or client (Bedrock/Vertex/Foundry); still omits `speed` from the request - Update anthropic_speed docstring to document the warning behavior - Move `import anthropic` and `AsyncMock, MagicMock` out of test_anthropic_speed_omitted_on_non_direct_clients to the top of tests/models/test_anthropic.py - Update tests to assert the warning (UserWarning with match) for the 'fast' + unsupported-model and non-direct-client cases

Reverts the UserWarning added in 015d076. Per DouweM's review (2026-02-13) and pydantic_ai/models/AGENTS.md, unsupported model settings must be silently ignored at runtime; the field docstring already documents the limit. Also reverts the docs note added in 71db952.

…rning)" This reverts commit cc9e2f7.

Per DouweM's review, the two-call split in `prepare_request` was deliberate: warn once against the user's input early, then silently scrub any sampling params re-introduced by the post-`super().prepare_request` merge of defaults. Earlier branch commits collapsed the two calls into one (e7aa77a) and then removed the now-unused `warn` param for coverage (a44ad41), which moved the warning point and could fire for params the user never set. This restores the original main-branch structure.

Co-authored-by: devin-ai-integration[bot] <158243242+devin-ai-integration[bot]@users.noreply.github.com> Co-authored-by: Cursor <[email protected]> Co-authored-by: David Sanchez <[email protected]>

Add anthropic speed

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github-actions Bot added size: S Small PR (≤100 weighted lines) feature New feature request, or PR implementing a feature (enhancement) labels Feb 11, 2026

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bohdanhr changed the title ~~Add anthropic speed~~ Add anthropic speed, fast mode for opus 4.6 Feb 11, 2026

more coverage

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fix coverage

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address pr comments

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bohdanhr commented Feb 12, 2026

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Comment thread pydantic_ai_slim/pydantic_ai/profiles/anthropic.py Outdated

Merge branch 'main' into add-anthropic-speed

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bohdanhr requested a review from DouweM February 12, 2026 10:58

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bohdanhr and others added 4 commits February 12, 2026 15:04

Update pydantic_ai_slim/pydantic_ai/profiles/anthropic.py

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hook up to check if model is supported

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format

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dsfaccini reviewed Apr 17, 2026

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Comment thread docs/models/anthropic.md Outdated

remove skip

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dsfaccini added 2 commits April 22, 2026 14:44

Merge branch 'main' into add-anthropic-speed

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dsfaccini reviewed Apr 23, 2026

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Revert unintended tests/AGENTS.md additions

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dsfaccini added 3 commits April 24, 2026 17:40

Align fast-mode docs with code: 'ignored with UserWarning'

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Merge branch 'main' into add-anthropic-speed

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dsfaccini and others added 6 commits April 26, 2026 17:50

Revert "Silently ignore unsupported anthropic_speed='fast' (revert wa…

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…rning)" This reverts commit cc9e2f7.

remove ignore

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improve readability

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Parametrize non-direct client test with class objects

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Merge branch 'main' into add-anthropic-speed

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dsfaccini merged commit f0b1947 into pydantic:main Apr 28, 2026
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		from unittest.mock import AsyncMock, MagicMock

		import anthropic

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bohdanhr commented Feb 11, 2026 •

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