docs: add Codex plugin installation instructions to README

[xingyaoww]

• A human has tested these changes.

---

Why

Users of OpenAI Codex should be able to discover how to install extensions from this repository, similar to the existing Claude Code instructions.

Summary

• Added a collapsible "Using Codex?" section to the README Quick Start area, right after the existing "Using Claude Code?" section.
• Documents the codex plugin marketplace add command and how to browse installed extensions via /plugins.

How to Test

Review the rendered README on the PR branch — the new <details> block should appear under Quick Start, after the Claude Code section.

Notes

This PR was created by an AI agent (OpenHands) on behalf of the user.

@xingyaoww can click here to continue refining the PR

[all-hands-bot]

🟡 Acceptable - Structure mirrors the Claude Code section well, but needs verification that Codex actually supports this feature.

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟡 MEDIUM
  Documentation-only change with no code impact, but unverified instructions could confuse users if the feature doesn't exist or the syntax is incorrect.

VERDICT:
⏸️ Needs verification: Please confirm Codex supports these commands before merging.

KEY INSIGHT:
Documentation accuracy is just as important as code correctness - unverified integration instructions can mislead users.

---

Improve this review? If any feedback above seems incorrect or irrelevant to this repository, you can teach the reviewer to do better:

1. Add a .agents/skills/custom-codereview-guide.md file to your branch (or edit it if one already exists) with the /codereview trigger and the context the reviewer is missing (e.g., "Security concerns about X do not apply here because Y"). See the customization docs for the required frontmatter format.
2. Re-request a review - the reviewer reads guidelines from the PR branch, so your changes take effect immediately.
3. When your PR is merged, the guideline file goes through normal code review by repository maintainers.

Resolve with AI? Install the iterate skill in your agent and run /iterate to automatically drive this PR through CI, review, and QA until it's merge-ready.

[all-hands-bot]

🟡 Acceptable structure - Documentation organization improved, but verification required before merge.

[CRITICAL ISSUES]

• [README.md, Lines 75-90] Unverified Feature: The Codex plugin marketplace commands are documented without evidence that this feature exists. See unresolved thread for details.

[IMPROVEMENT OPPORTUNITIES]

• [scripts/sync_extensions.py] The Quick Start section was removed from auto-generation and is now manually maintained. This is acceptable but should be documented in team knowledge.

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟡 MEDIUM
  Documentation-only change with no code impact, but unverified instructions could confuse users and damage credibility if the feature doesn't exist or syntax is incorrect.

VERDICT:
❌ Needs verification: Address the unresolved thread by providing evidence that Codex supports these commands, or remove the Codex section.

KEY INSIGHT:
Restructuring the README to prioritize Quick Start is good UX, but shipping unverified documentation is worse than not shipping it at all.

[xingyaoww]

Addressed feedback in 3f2a11a. The sync_extensions.py change is documented in AGENTS.md. Ready for another look.

[all-hands-bot]

🟡 Acceptable - Documentation structure improved, but Codex section needs more detail to match Claude Code completeness.

[IMPROVEMENT OPPORTUNITIES]

• [README.md, Lines 75-90] Incomplete Instructions: The Codex section only documents adding the marketplace and browsing plugins, but doesn't explain how to install specific plugins or activate them. The Claude Code section shows the full workflow including /plugin install and /reload-plugins. If Codex requires similar steps, add them for completeness.

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟢 LOW
  Documentation-only change with no code impact. If Codex instructions are incomplete, users may need to discover additional steps through trial-and-error, but this won't break any functionality.

VERDICT:
✅ Worth merging: Structure improvement is solid, minor completeness issue in new section

KEY INSIGHT:
Making Quick Start manually maintained gives better control over user-facing documentation presentation while keeping the catalog auto-generated.

[all-hands-bot]

---

Improve this review? If any feedback above seems incorrect or irrelevant to this repository, you can teach the reviewer to do better:

1. Add a .agents/skills/custom-codereview-guide.md file to your branch (or edit it if one already exists) with the /codereview trigger and the context the reviewer is missing (e.g., "Security concerns about X do not apply here because Y"). See the customization docs for the required frontmatter format.
2. Re-request a review - the reviewer reads guidelines from the PR branch, so your changes take effect immediately.
3. When your PR is merged, the guideline file goes through normal code review by repository maintainers.

Resolve with AI? Install the iterate skill in your agent and run /iterate to automatically drive this PR through CI, review, and QA until it's merge-ready.

[all-hands-bot]

🟡 Acceptable - Documentation structure is clean and follows established patterns, with one minor inconsistency worth noting.

[IMPROVEMENT OPPORTUNITIES]

• [README.md, Line 77] Link Inconsistency: The Codex section links to the Codex homepage (https://codex.openai.com) while the Claude Code section links to specific plugin marketplace documentation (https://code.claude.com/docs/en/discover-plugins). For consistency, either link to Codex's plugin marketplace docs if they exist publicly, or consider removing the link if the feature isn't yet documented.

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟢 LOW
  Documentation-only change with no code impact. Structure mirrors the proven Claude Code section pattern. AGENTS.md update properly documents the manual maintenance approach. If commands are incorrect, users will quickly report it and the fix is trivial.

VERDICT:
✅ Worth merging - Clean documentation structure with a minor link discrepancy that doesn't block adoption.

KEY INSIGHT:
Proper documentation of the Quick Start section's manual maintenance in AGENTS.md prevents future confusion about sync script behavior.

---

Improve this review? If any feedback above seems incorrect or irrelevant to this repository, you can teach the reviewer to do better:

1. Add a .agents/skills/custom-codereview-guide.md file to your branch (or edit it if one already exists) with the /codereview trigger and the context the reviewer is missing (e.g., "Security concerns about X do not apply here because Y"). See the customization docs for the required frontmatter format.
2. Re-request a review - the reviewer reads guidelines from the PR branch, so your changes take effect immediately.
3. When your PR is merged, the guideline file goes through normal code review by repository maintainers.

Resolve with AI? Install the iterate skill in your agent and run /iterate to automatically drive this PR through CI, review, and QA until it's merge-ready.

[xingyaoww]

@OpenHands /iterate until this PR is approved

[openhands-ai]

I'm on it! xingyaoww can track my progress at all-hands.dev

[xingyaoww]

Addressed link inconsistency feedback in 267efa9 — Codex section now links to developers.openai.com/codex/plugins (the plugin docs page) instead of the generic homepage, matching the Claude Code section's pattern. Ready for another look.

This comment was generated by an AI agent (OpenHands).

[all-hands-bot]

🟢 Good taste - Clean reorganization with consistent structure.

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟢 LOW

Documentation-only change that improves README organization by moving Quick Start above the catalog and using consistent collapsible sections. Easy to fix if any issues arise.

VERDICT:
✅ Approve - Well-structured documentation improvement.

KEY INSIGHT:
Consistent collapsible sections for all platform-specific setup instructions (SDK, Claude Code, Codex) creates a cleaner, more navigable README.

[openhands-ai]

Summary

The /iterate request has been fully addressed. Here's what was done:

Checklist

• Checked CI status — all 5 checks were already passing on the previous SHA
• Reviewed bot feedback — the latest all-hands-bot review (COMMENTED, not APPROVED) flagged one improvement: the Codex section linked to the generic homepage (codex.openai.com) while the Claude Code section linked to specific plugin docs
• Fixed the link inconsistency — updated the Codex link to developers.openai.com/codex/plugins (the actual plugin documentation page), matching the Claude Code section's pattern of linking to plugin-specific docs
• Committed and pushed — single commit 267efa9 with a clear message
• Re-requested review from all-hands-bot
• Polled CI — all 5 checks passed on the new SHA
• Bot approved — all-hands-bot gave 🟢 Good taste and APPROVED the PR
• Verified merge readiness — mergeStateStatus: CLEAN, mergeable: MERGEABLE, 0 unresolved threads

Conciseness

The change is minimal — a single line edit in README.md updating one URL. No extraneous changes were made.

Result

PR #223 is now approved and merge-ready at #223.