# sdk: v0.129.0

Category: model-behavior
Published: 2026-09-28T18:03:48Z
Source: [Anthropic TypeScript SDK releases](https://github.com/anthropics/anthropic-sdk-typescript/releases/tag/sdk-v0.129.0)
Agent usefulness: 77/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-09-29T00:17:29.259Z
Tags: anthropic, sdk, typescript

## Human Summary
Anthropic TypeScript SDK releases published sdk: v0.129.0. 0.129.0 (2026-09-28) Full Changelog: sdk-v0.128.0...sdk-v0.129.0 Features api: add between tools thinking type ( ab51075 ) api: add claude-sonnet-5-5 ( 4e77366 ) api: add ClientToolUnion type for client-executed tools ( 2c1d2d7 ) api: add include inherited and source to workspace rate limits (…

## Agent Summary
Treat sdk: v0.129.0 as an official release signal. Inspect the linked changelog for compatibility and migration details, then run targeted tests before upgrading.

## Body
Anthropic TypeScript SDK releases published sdk: v0.129.0. This automated release-watch entry was generated from the project's official GitHub release feed and is kept separate from human-reviewed editorial analysis. Release notes: 0.129.0 (2026-09-28) Full Changelog: sdk-v0.128.0...sdk-v0.129.0 Features api: add between tools thinking type ( ab51075 ) api: add claude-sonnet-5-5 ( 4e77366 ) api: add ClientToolUnion type for client-executed tools ( 2c1d2d7 ) api: add include inherited and source to workspace rate limits ( 66e925e ) api: add typed event type values to the Managed Agents events list filter ( 8ac4a26 ) api: cache diagnostics GA — diagnostics on Message / MessageCreateParams ( 5ba5f29 ) tools: optionally start tool calls while the reply streams ( 083969b ) Bug Fixes client: also send X-Stainless-Timeout for client-level timeouts ( b84783b ) client: send upload filenames as given, with no placeholder ( f9d3e98 ) helpers: degrade between tools thinking to disabled on fallback hops ( 841 ) ( edbbf05 ) internal: let bundlers drop unused classes with more than ten private-member assignments ( 67c7adb )…

## Recommended actions
- Review the official Anthropic TypeScript SDK releases release notes before upgrading.
- Check compatibility, migration, and security notes against your current agent stack.
- Run focused regression tests before production rollout.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.