anthropics/anthropic-sdk-go v1.20.0

on GitHub

1.20.0 (2026-01-29)

Full Changelog: v1.19.0...v1.20.0

Features

• api: add support for Structured Outputs in the Messages API (10c3821)
• api: migrate sending message format in output_config rather than output_format (f996db4)
• client: add a convenient param.SetJSON helper (427514e)
• encoder: support bracket encoding form-data object members (eaaeadf)

Bug Fixes

• accumulator: revert to marshal accumulator on stop events (#563) (096a8a8)
• client: retain streaming when user sets request body (6d073fe)
• docs: add missing pointer prefix to api.md return types (23aaf6d)
• mcp: correct code tool API endpoint (6c8a083)
• rename param to avoid collision (6d1cf75)
• streaming endpoints should pass through errors correctly (e584c87)
• to-param: remove panics and add cases (#524) (f689816)

Chores

• add float64 to valid types for RegisterFieldValidator (b6bec73)
• ci: Add Claude Code GitHub Workflow (a151836)
• client: improve example values (8af69b8)
• client: mark claude-3-5-haiku as deprecated (dcac65c)
• elide duplicate aliases (c8e2ee1)
• internal: codegen related update (931c976)
• internal: update actions/checkout version (3bd83ec)
• internal: use different example values for some enums (f2d46b8)