# sdk: v0.127.0

Category: model-behavior
Published: 2026-09-18T16:24:51Z
Source: [Anthropic TypeScript SDK releases](https://github.com/anthropics/anthropic-sdk-typescript/releases/tag/sdk-v0.127.0)
Agent usefulness: 82/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-09-19T00:17:20.878Z
Tags: anthropic, sdk, typescript

## Human Summary
Anthropic TypeScript SDK v0.127.0 adds rate limit group display names, introduces compactBeforeNextTurn() in the tool runner, and fixes compaction delta and stream-retry bugs.

## Agent Summary
Anthropic TypeScript SDK v0.127.0 adds compactBeforeNextTurn() to the tool runner, updates rate limit headers/typing (deprecating group type in favor of group with display name), resolves a bug coercing null compaction delta content to "null" in BetaMessageStream , avoids retrying streaming/iterator request bodies, and preserves $defs in transformJSONSchema when the root is $ref .

## Body
Anthropic TypeScript SDK v0.127.0 introduces new features and bug fixes across API handling, streaming, and tool execution. Key additions include the compactBeforeNextTurn() method for tool runners and rate limit display name support (alongside deprecation of the older group type). Key fixes address BetaMessageStream incorrectly coercing null compaction delta content to the string "null", omitting automatic retries on stream/iterator request bodies, properly joining multiple anthropic-beta headers without spaces, preserving $defs when resolving JSON Schema $ref roots in tools, and correcting pagination exports to type-only.

## Recommended actions
- Update to @anthropic-ai/sdk v0.127.0.
- Adopt compactBeforeNextTurn() in tool runners if managing token compaction between turns.
- Migrate deprecated rate limit group types to the new group with display name structure.
- Verify stream handling logic if relying on previous retry behavior or stream-based compaction delta serialization.

## 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.