Old Coder skill for Codex
An old coder's strategy for the agent era: don't read the code — make it run the gauntlet. Evidence-first development skill for coding agents, inspired by Uncle Bob.
How to install Old Coder in Codex
In Codex, ask the built-in skill installer for it:
$skill-installer install https://github.com/AmazingAng/old-coder/tree/main/skills/<skill>Type this in Codex and replace <skill> with a folder name from 'What it contains'. $skill-installer is the skill installer built into Codex, and it downloads the skill from GitHub. Restart Codex if the skill doesn't show up. Check the repo README for any setup it needs. Source: Codex skills docs.
Or copy the skill folder (the one with SKILL.md) into ~/.agents/skills to use it in every project, or into .agents/skills in a repo to share it with that repo. Codex picks up new skills automatically. (where Codex loads skills)
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What it contains
Skills (2)
old-coder-api— Design, change, or review an HTTP/JSON API surface — endpoints, request/response shapes, authentication and authorization, pagination, idempotency, rate limits, versioning, and deprecations. Use when adding or modifying an HTTP endpoint, reviewing an OpenAPI…old-coder— Evidence-first development — surround the implementation with an executable spec and a gauntlet of constraints (tests, types, coverage, mutation) so line-by-line review becomes optional. Use when the user explicitly asks for high-assurance or evidence-first…
About this listing
Old Coder is a community collection of agent skills on GitHub by AmazingAng: folders with a SKILL.md file, the format Codex loads skills from. Its README mentions Codex. It passed the CodexStacks quality filter for skills (at least 100 stars, pushed in the last 90 days, not a fork or a list, and at least one SKILL.md with a name and description). OpenAI hasn't reviewed it, but it passed our Codex install check on Oct 29, 2026 (an install and load check, not a code review). From its files we found 2 skills. It's one of 441 listings in the Developer Tools category (category assigned by CodexStacks from the repo's topics and description).
Old Coder FAQ
How do I install Old Coder in Codex?
In Codex, type $skill-installer install https://github.com/AmazingAng/old-coder/tree/main/skills/<skill>. $skill-installer is the skill installer built into Codex (Codex skills docs). Or copy the skill folder (the one with SKILL.md) into ~/.agents/skills to use it in every project, or into .agents/skills in a repo to share it with that repo. Codex picks up new skills automatically.
Is Old Coder an official Codex skill?
No. Old Coder is a community repo on GitHub by AmazingAng. It passed the CodexStacks quality filter, but OpenAI hasn't reviewed it, but it passed our Codex install check on Oct 29, 2026 (an install and load check, not a code review), so read the code before you install it.
What does Old Coder include?
From its manifest and repo files, Old Coder includes 2 skills: old-coder-api, old-coder.
Details
- Type
- Skill
- Category
- Developer Tools (assigned by us)
- Source
- Community
- Author
- AmazingAng
- License
- MIT
- GitHub stars
- 753 (at last sync)
- Last push
- 2026-08-18
- GitHub topics
- ai-agents, ai-coding, claude-code, code-quality, cursor, llm, mutation-testing, property-based-testing, software-testing, spec-driven-development, tdd
- Source
- https://github.com/AmazingAng/old-coder
- Listed via
- GitHub search: Codex skills (SKILL.md)
- Install check by CodexStacks
- Passed on Oct 29, 2026 with Codex CLI 0.163.0: Codex loaded its skills. proof · how we check
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For maintainers: badge and embeds
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Markdown
[](https://codexstacks.com/p/old-coder/)HTML
<a href="https://codexstacks.com/p/old-coder/"><img src="https://codexstacks.com/badge.svg" alt="Listed on CodexStacks" width="172" height="28"></a>Embed card (static HTML and inline CSS, no JavaScript). Preview:
<a href="https://codexstacks.com/p/old-coder/" style="display:block;max-width:380px;box-sizing:border-box;padding:14px 16px;border:1px solid #3a2c26;border-radius:12px;background:#0d0b0a;color:#f3ece6;font:14px/1.45 -apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;text-decoration:none"><span style="display:block;font-size:16px;font-weight:700;color:#f3ece6">Old Coder</span><span style="display:block;margin:2px 0 8px;font-size:12px;color:#b5a9a1">Community Codex skill · 2 skills</span><span style="display:block;margin:0 0 10px;color:#ddd3cc">An old coder's strategy for the agent era: don't read the code — make it run the gauntlet. Evidence-first development…</span><span style="font-size:12px;font-weight:600;color:#ffb347">View on CodexStacks →</span></a>Markdown summary
**[Old Coder on CodexStacks](https://codexstacks.com/p/old-coder/)**: Community Codex skill with 2 skills.More on badges, embeds and keeping your listing up to date: CodexStacks for plugin authors.
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