sdk: v0.128.0
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.
Why this signal matters
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.
Actionable 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.
- Agent usefulness
- 82/100
- Confidence
- 96%
- Canonical data
- JSON + Markdown
What builders should check
- 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.