# sdk: v0.128.0

Category: model-behavior
Published: 2026-09-22T16:27:55Z
Source: [Anthropic TypeScript SDK releases](https://github.com/anthropics/anthropic-sdk-typescript/releases/tag/sdk-v0.128.0)
Agent usefulness: 82/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-09-22T18:17:21.840Z
Tags: anthropic, sdk, typescript

## Human Summary
Anthropic TypeScript SDK v0.128.0 adds support for claude-opus-5-5, inline tool definitions, and MCP tool-list pinning (beta), alongside fixes for dynamic tool registration and compaction requests.

## Agent Summary
Anthropic TypeScript SDK updated to v0.128.0: added beta support for model claude-opus-5-5, inline tool definitions, and MCP tool-list pinning. Fixed addTools() immediate application bug, excluded reply-only params from compaction requests, and unified evaluated permission enums across Managed Agents events.

## Body
Anthropic TypeScript SDK v0.128.0 introduces several new features and bug fixes. Key additions include beta API support for claude-opus-5-5, inline tool definitions, and MCP tool-list pinning. The release also includes bug fixes: ensuring addTools() takes effect immediately ( 773), omitting reply-only parameters from the tool runner compaction requests ( 769), and standardizing an evaluated permission enum across Managed Agents events. Documentation updates cover the Dreams API, User Profiles API, and Managed Agents memory store descriptions.

## Recommended actions
- Upgrade @anthropic-ai/sdk to version 0.128.0 to use the new claude-opus-5-5 model or MCP tool-list pinning beta features.
- Verify tool runner workflows to benefit from immediate addTools() updates and cleaner compaction requests.

## 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.