fix(anthropic): constrain SDK below v1

[HareeshBahuleyan]

Description

Constrain the supported Anthropic SDK range to >=0.119.0,<1 until the SDK 1.x provider migration is complete (#1370).

Anthropic SDK 1.x removed temperature, top_p, and top_k from the Messages method signatures while the current provider still forwards those parameters directly. This causes common completion and native Messages requests to fail before reaching the transport. Version 0.119 and later retain the typed refusal and container functionality introduced through #1328.

This change:

• applies the upper bound to the core, Vertex Anthropic, and Azure Anthropic dependency declarations
• restores Anthropic transport tests to httpx, which is the transport used by SDK 0.x
• adds real SDK transport coverage for completion, native Messages, and streaming sampling parameters
• covers container and service tier serialization through the concrete SDK client

The upper bound can be removed when the SDK 1.x migration in #1347 is complete and released.

PR Type

• 🐛 Bug Fix

Relevant issues

• Preserves the functionality added in fix(providers): preserve typed safety refusals #1328
• Follow-up migration: fix(anthropic): align SDK v1 requests and effort controls #1347

Checklist

• I understand the code I am submitting.
• I have added unit tests that prove my fix/feature works
• I have run this code locally and verified it fixes the issue.
• New and existing tests pass locally
• Documentation was updated where necessary (no user-facing API or behavior documentation changed)
• I have read and followed the contribution guidelines
• AI Usage:
  • No AI was used.
  • AI was used for drafting/refactoring.
  • This is fully AI-generated.

AI Usage Information

• AI Model used: GPT-5
• AI Developer Tool used: Codex
• Any other info you would like to share: The Anthropic v1 migration notes were reviewed and the sampling-signature failure was reproduced against the concrete SDK client before adding the temporary compatibility bound.

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Summary by CodeRabbit

• Compatibility
  • Updated the supported Anthropic SDK range to versions from 0.119.0 up to, but not including, 1.0.0.
  • This compatibility range applies to core Anthropic integrations and the Vertex AI and Azure optional integrations.

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Team

Run ID: bbbf0ee8-3e11-4792-a870-63d87b0929ed

📥 Commits

Reviewing files that changed from the base of the PR and between c1f167b and 332d66f.

📒 Files selected for processing (2)

• pyproject.toml
• tests/unit/providers/test_anthropic_messages.py

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Walkthrough

Changes

The Anthropic dependency now has an upper version bound below 1. Messages API tests add parameter-forwarding coverage and migrate HTTP test clients and handlers from httpx2 to httpx.

Anthropic Messages API

Layer / File(s)	Summary
Anthropic dependency bounds pyproject.toml	The core dependency and optional Anthropic extras require >=0.119.0,<1.
Message parameter forwarding tests tests/unit/providers/test_anthropic_messages.py	Tests cover completion and native Messages API parameters, including sampling, container, and service tier values.
HTTP transport migration tests/unit/providers/test_anthropic_messages.py	Existing handlers, responses, and asynchronous clients use httpx instead of httpx2.
Streaming parameter assertions tests/unit/providers/test_anthropic_messages.py	The accumulated streaming test checks forwarded temperature, top-p, and top-k values.

Suggested reviewers: njbrake

Merge Risk: ⚪ Minimal · up to 332d6

This change prevents incompatible Anthropic SDK 1.x installations while retaining existing Messages sampling behavior, with coverage for normal and streaming requests. No current merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 10.71% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 28 functions across 1 files. (1 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the main change: constraining the Anthropic SDK below version 1.
Description check	✅ Passed	The description is complete and relevant. It explains the temporary SDK constraint, affected dependencies, compatibility reason, test coverage, related issues, checklist status, and AI usage.

Full details: Docstring Coverage

Explanation

Docstring coverage is 10.71% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 28 functions across 1 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/anthropic-pre-v1-constraint

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
see 32 files with indirect coverage changes

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[Copilot]

🟢 Approval recommended

The dependency constraint matches the stated incompatibility, and the updated unit tests provide direct coverage that the SDK 0.x transport path serializes the affected parameters correctly.

Pull request overview

Constrains the Anthropic Python SDK dependency to >=0.119.0,<1 across core and related extras to prevent runtime request failures caused by SDK 1.x signature changes, while keeping the 0.119+ features relied on by the current provider implementation.

Changes:

• Pin anthropic to >=0.119.0,<1 in core deps and the vertexaianthropic and azureanthropic optional dependency sets.
• Update Anthropic Messages unit tests to use httpx transport (SDK 0.x) instead of httpx2.
• Add unit tests that exercise real SDK request serialization for completion, native Messages, and streaming, including sampling and related parameters.

File summaries

File	Description
tests/unit/providers/test_anthropic_messages.py	Switches mocked transport to httpx and adds concrete SDK transport assertions for sampling and related request fields.
pyproject.toml	Adds an upper bound <1 to Anthropic SDK dependencies (core, Vertex Anthropic, Azure Anthropic) to avoid SDK 1.x incompatibilities.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Lite

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