feat(builds): add build_args support to CreateBuild API

[hiroTamada]

Summary

• Expose the existing BuildArgs field through the CreateBuild API
• Accept build_args as a JSON object in the multipart form (e.g., {"NODE_ENV": "production"})
• Args are passed to buildctl as --opt build-arg:KEY=VALUE

Test plan

• Tested with a Dockerfile containing ARG instructions
• Verified build args appear in buildctl command line
• Verified build completes successfully with args applied
• Verified invalid JSON returns proper error message

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Note

Low Risk
Small, additive change to request parsing and API schema; main risk is backward-compatible but could reject previously-accepted malformed build_args inputs or surface parsing errors.

Overview
The CreateBuild API now accepts an optional build_args multipart field containing a JSON object of key/value pairs, validates it, and forwards the parsed map into the builds.CreateBuildRequest sent to BuildManager.

The OpenAPI spec and generated oapi types are updated to document build_args (as a JSON-encoded string in the multipart body), and the embedded swagger blob is regenerated accordingly.

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[github-actions]

✱ Stainless preview builds

This PR will update the hypeman SDKs with the following commit message.

feat(builds): add build_args support to CreateBuild API

Edit this comment to update it. It will appear in the SDK's changelogs.

✅ hypeman-typescript studio · code · diff

Your SDK built successfully.
generate ⚠️ → build ✅ → lint ✅ → test ✅

npm install https://pkg.stainless.com/s/hypeman-typescript/c41baa9d59b13ce1894f333ec60589383dcac35a/dist.tar.gz

✅ hypeman-go studio · code · diff

Your SDK built successfully.
generate ⚠️ → lint ✅ → test ✅

go get github.com/stainless-sdks/hypeman-go@fd0dc364908b2063d095cac6f1799e02e38a4de0

⏳ hypeman-cli studio · conflict

⏳ These are partial results; builds are still running.

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Last updated: 2026-02-06 17:01:42 UTC