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Python: feat(anthropic): Add response_format support for structured outputs#3301

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eavanvalkenburg merged 8 commits intomicrosoft:mainfrom
sukeesh:sukeesh/fix-structured-output-anthropic
Jan 21, 2026
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Python: feat(anthropic): Add response_format support for structured outputs#3301
eavanvalkenburg merged 8 commits intomicrosoft:mainfrom
sukeesh:sukeesh/fix-structured-output-anthropic

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@sukeesh sukeesh commented Jan 20, 2026

Motivation and Context

The Anthropic client was missing response_format handling, which is
supported by OpenAI and Azure AI clients. This adds structured output
support using Anthropic's tool use feature.

Changes:

  • Add _create_response_format_tool to convert Pydantic models to tool definitions
  • Force model to use the response format tool when response_format is provided
  • Convert tool call arguments to TextContent for JSON parsing
  • Pass response_format to ChatResponse constructor to trigger try_parse_value

This enables consistent response_format usage across all chat clients.

Contribution Checklist

  • The code builds clean without any errors or warnings
  • The PR follows the Contribution Guidelines
  • All unit tests pass, and I have added new tests where possible
  • Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

@github-actions github-actions bot changed the title fix(anthropic): Add response_format support for structured outputs Python: fix(anthropic): Add response_format support for structured outputs Jan 20, 2026
@sukeesh sukeesh changed the title Python: fix(anthropic): Add response_format support for structured outputs Python: feat(anthropic): Add response_format support for structured outputs Jan 20, 2026
eavanvalkenburg
eavanvalkenburg reviewed Jan 20, 2026
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eavanvalkenburg approved these changes Jan 20, 2026
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LGTM, thanks!

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markwallace-microsoft commented Jan 20, 2026 •
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Python Test Coverage

Python Test Coverage Report •
FileStmtsMissCoverMissing
packages/anthropic/agent_framework_anthropic
   _chat_client.py36015158%51, 361, 384, 386, 401, 423–426, 435, 437, 468–472, 474, 476–477, 479, 484–485, 487, 518–519, 528, 530–531, 536, 553–554, 596, 611, 615–616, 632, 641, 643, 647–648, 691–693, 695, 708–709, 716–718, 722–724, 728–731, 742, 744, 766, 776, 798–804, 811–812, 820–821, 829–832, 839–840, 846–847, 853–854, 860, 868–870, 874, 881–882, 888–889, 895–896, 902, 910–913, 920–921, 940, 947–948, 967, 989, 991, 1000–1001, 1007, 1029–1030, 1036–1037, 1046–1056, 1063–1069, 1076–1082, 1089–1098, 1105–1108
TOTAL17473271284% 

Python Unit Test Overview

Tests Skipped Failures Errors Time
3186 213 💤 0 ❌ 0 🔥 1m 9s ⏱️

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sukeesh commented Jan 21, 2026

@dmytrostruk / @victordibia / @moonbox3 Can I get your review as well on this?

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sukeesh commented Jan 21, 2026 •
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@dmytrostruk @eavanvalkenburg Can you please re-review? I fixed the ruff lint issue that it was complaining.

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sukeesh commented Jan 21, 2026

cc @moonbox3

@eavanvalkenburg eavanvalkenburg added this pull request to the merge queue Jan 21, 2026
Merged via the queue into microsoft:main with commit 082f39e Jan 21, 2026
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@sukeesh sukeesh deleted the sukeesh/fix-structured-output-anthropic branch January 22, 2026 06:08
arisng pushed a commit to arisng/agent-framework that referenced this pull request Feb 2, 2026
@sukeesh
Python: feat(anthropic): Add response_format support for structured o…
7d0f5fe 
…utputs (microsoft#3301)

* fix(anthropic): Add response_format support for structured outputs

* only use from options

* use native way of response format

* ruff lint fix

* address comment; handle dict
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@eavanvalkenburg eavanvalkenburg eavanvalkenburg approved these changes

@dmytrostruk dmytrostruk dmytrostruk approved these changes

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@sukeesh @markwallace-microsoft @eavanvalkenburg @dmytrostruk

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