fix(xai): translate Codex namespace tools for Responses

[kakaholigan]

Summary

• flatten Codex 0.148 namespace tool containers only for xAI Responses transports
• preserve every callable child and restore non-builtin namespaces on JSON/SSE tool calls
• fail closed on malformed, unsupported, duplicate, or colliding namespace catalogs
• keep non-xAI Responses requests byte-compatible

Verification

• bun test tests/xai-responses-namespace-tools.test.ts (6 pass)
• related xAI/Responses suites (86 pass)
• bun run typecheck
• bun run privacy:scan

The full repository suite was also started; the host run reports pre-existing environment failures in GUI tests because React dependencies are not installed and Bun 1.3.14 EEXIST: epoll_ctl test-runner errors. The focused and adjacent suites are green.

Review readiness checklist

This PR stays in draft until every box below is ticked. Tick all four boxes once the requirements are met:

• All CI tests are green on my local testing.

• I pushed my PR to the latest dev commit.

• I resolved all correct Codex and CodeRabbit findings.

• My PR is ready for review.

[coderabbitai]

Important

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: aed32c38-4cde-46e3-91ef-cbdc3d7d157f

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

✅ Deterministic PR hygiene checks passed.

[github-actions]

⏳ DRAFT

• review readiness checklist open (0/4 boxes ticked).

What to do

• Tick all four boxes in the PR description once you're done (currently 0/4).

Review readiness checklist

• ⬜ All CI tests are green on my local testing.
• ⬜ I pushed my PR to the latest dev commit.
• ⬜ I resolved all correct Codex and CodeRabbit findings.
• ⬜ My PR is ready for review.

0/4 boxes ticked.

This PR stays in draft until every box above is ticked.

[Ingwannu]

Thanks for working on the Grok Responses regression. I am closing this as superseded by #2217 rather than asking both branches to evolve in parallel.

The two PRs own the same namespace-tool translation boundary and would conflict. #2217 is already the reviewed sequential fix for the first-turn failure in #2240, has exact-head green CI, and covers the full observed request shape: namespace declaration/selector/replay/SSE restoration plus removal of the Codex-private external_web_access and defer_loading fields. This draft currently handles the namespace container but does not remove those additional fields, so it would not by itself repair the captured first-turn request.

The xAI-specific transport classifier here is a reasonable design idea, but it is not enough reason to maintain a second incompatible implementation. Please move any concrete edge case that #2217 does not cover into that PR or #2240 instead.