# Anthropic TypeScript SDK v0.103.0 — sdk: v0.103.0

- Product: Anthropic TypeScript SDK (https://whatsnew.fyi/product/anthropic-sdk-typescript)
- Vendor: Anthropic
- Date: 2026-06-09
- Version: v0.103.0
- Original notes: https://github.com/anthropics/anthropic-sdk-typescript/releases/tag/sdk-v0.103.0
- Permalink: https://whatsnew.fyi/product/anthropic-sdk-typescript/releases/v0.103.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **added** — Add support for claude-mythos-5 and claude-fable-5 models with server-side fallbacks on refusal
- **added** — Add client-side fallbacks middleware for API providers that do not support server-side fallbacks
- **added** — Add ctx.logger to middleware
- **fixed** — Fix third-party middleware ordering

##### 0.103.0 (2026-06-09)

Full Changelog: [sdk-v0.102.0...sdk-v0.103.0](https://github.com/anthropics/anthropic-sdk-typescript/compare/sdk-v0.102.0...sdk-v0.103.0)

###### Features

* **api:** add support for claude-mythos-5 and claude-fable-5, with support for server-side fallbacks on refusal ([cc337f7](https://github.com/anthropics/anthropic-sdk-typescript/commit/cc337f72dcf22d2ffd92f511918330f37ffab652))
* **client:** adds client-side fallbacks middleware for API providers that do not support server-side fallbacks ([cc337f7](https://github.com/anthropics/anthropic-sdk-typescript/commit/cc337f72dcf22d2ffd92f511918330f37ffab652))
* **middleware:** add ctx.logger ([#55](https://github.com/anthropics/anthropic-sdk-typescript/issues/55)) ([edd1454](https://github.com/anthropics/anthropic-sdk-typescript/commit/edd14544173cf60ee2a2bf01acbf14e50bcfdaaa))


###### Bug Fixes

* **client:** 3p middleware ordering ([#53](https://github.com/anthropics/anthropic-sdk-typescript/issues/53)) ([2a4c339](https://github.com/anthropics/anthropic-sdk-typescript/commit/2a4c339e6887aa2e8e1278c7b22d3732cf64a76c))