Add a Custom language option to OpenAPI code samples

[zenoachtig]

Overview

• Adds a Custom language option to the language dropdown of OpenAPI code-sample blocks. Selecting it opens the GitBook Assistant pre-filled as a draft (not sent) — with the current request staged as a reference and the prompt "Rewrite this in the following language: " — so readers can get the request in any language they want.
• The Custom option shows the primary Assistant logo, a Custom language label, and a Rewrite with {assistantName} subtitle, set apart from the built-in languages by a separator.
• Every other option (HTTP, cURL, JavaScript, Python, and custom x-codeSamples languages) now shows a language icon in the dropdown.

Implementation notes

• @gitbook/react-openapi renders the dropdown but can't import the app's AI code, so the assistant is bridged in through a new OpenAPICodeSampleAssistant React context ({ label, icon, onRewrite }). The Custom option only appears when that context is provided.
  • OpenAPISelect gains an action/onAction concept so an item can trigger a side effect without changing the persisted selection (the dropdown stays on the previously selected language).
  • Per-language icons come from a new optional getCodeSampleIcon on the render context; the currently displayed code is read from the panel at click time.
  • Adds 3 translation keys across all 9 locales.
• gitbook: a new setDraft controller method + inputDraft state lets the chat input be pre-filled without sending (this didn't exist before). OpenAPICodeSampleAIProvider supplies the assistant logo/name and the addReference + setDraft + open action, mounted once in SpaceLayout (covers both the site and the embed). getOpenAPIContext maps languages to icons.

Demo

Verified locally against GitBook's own API reference (assistant enabled):

• The dropdown shows HTTP / cURL / JavaScript / Python — each with a language icon — then a separator and Custom language with the assistant logo and the Rewrite with GitBook Assistant subtitle.

• Clicking Custom language opens the assistant with the code staged as a </> HTTP reference chip and the input pre-filled with "Rewrite this in the following language: " — not sent (no message posted), with the code-sample selector still on the previously selected language.

Validated with bun run typecheck, bun run build, Biome, and the react-openapi unit suite (196 passing).

— Authored by Claude

[changeset-bot]

🦋 Changeset detected

Latest commit: ac15ae7

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@gitbook/react-openapi	Minor
gitbook	Patch

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[github-actions]

Summary of the deployments:

Version	URL	Status
Vercel	https://gitbook-v2-ig5ev288d-gitbook.vercel.app	✅
Cloudflare	https://363e7734-gitbook-open-v2-preview.gitbook.workers.dev	✅

Test content

Site	2v	2c
GitBook	https://gitbook-v2-ig5ev288d-gitbook.vercel.app/url/gitbook.com/docs	https://363e7734-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.com/docs
E2E	https://gitbook-v2-ig5ev288d-gitbook.vercel.app/url/gitbook.gitbook.io/test-gitbook-open	https://363e7734-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.gitbook.io/test-gitbook-open

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Build	Status	Details	Updated (UTC)
customers-v2-cloudflare (Inspect)	✅ No changes detected	-	Jun 25, 2026, 2:08 PM
customers-v2-vercel (Inspect)	✅ No changes detected	-	Jun 25, 2026, 2:08 PM
v2-cloudflare (Inspect)	✅ No changes detected	-	Jun 25, 2026, 2:15 PM
v2-vercel (Inspect)	⚠️ Changes detected (Review)	4 changed	Jun 25, 2026, 2:15 PM