Retrospective Codify
mizchi/skills
Pair "what failed first" with "what finally worked" and codify the should-have-known-it insight as an ast-grep rule, a skill, or a CLAUDE.md rule.
A skill your agent uses when you want Codex to review its own recent history (last N days or specific period) and improve its behavior.
Install Codex Retrospective
$ npx skills add majiayu000/spellbook --skill codex-retrospective -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install majiayu000/spellbook codex-retrospective --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/codex-retrospective .claude/skills/codex-retrospective && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "codex-retrospective" agent skill from https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospective into .claude/skills/codex-retrospective/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-retrospective", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospectiveType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add majiayu000/spellbook --skill codex-retrospective -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install majiayu000/spellbook codex-retrospective --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/codex-retrospective .agents/skills/codex-retrospective && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "codex-retrospective" agent skill from https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospective into .agents/skills/codex-retrospective/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-retrospective", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add majiayu000/spellbook --skill codex-retrospective -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install majiayu000/spellbook codex-retrospective --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/codex-retrospective .cursor/skills/codex-retrospective && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "codex-retrospective" agent skill from https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospective into .cursor/skills/codex-retrospective/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-retrospective", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/majiayu000/spellbook.git --path skills/codex-retrospective--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add majiayu000/spellbook --skill codex-retrospective -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install majiayu000/spellbook codex-retrospective --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/codex-retrospective .gemini/skills/codex-retrospective && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "codex-retrospective" agent skill from https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospective into .gemini/skills/codex-retrospective/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-retrospective", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install majiayu000/spellbook codex-retrospectiveInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add majiayu000/spellbook --skill codex-retrospective -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/codex-retrospective .github/skills/codex-retrospective && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "codex-retrospective" agent skill from https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospective into .github/skills/codex-retrospective/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-retrospective", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add majiayu000/spellbook --skill codex-retrospective -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install majiayu000/spellbook codex-retrospective --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/codex-retrospective .opencode/skills/codex-retrospective && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "codex-retrospective" agent skill from https://github.com/majiayu000/spellbook/tree/main/skills/codex-retrospective into .opencode/skills/codex-retrospective/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-retrospective", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
codex-retrospective- GitHub stars
- 287
- Token cost
- ~1.6k tokens
- SKILL.md length
- 835 words
- Files
- 5 (incl. references)
- Skills in repo
- 97
- Repo updated
- First seen
- Licence
- MIT
At a glance
A skill your agent uses when you want Codex to review its own recent history (last N days or specific period) and improve its behavior.
- Works in 5 steps: Scope Definition → Evidence Collection Preflight → History Analysis (The Skill Guides Codex) → …
- You want Codex to review its own recent history (last N days
- SKILL.md covers Why This Exists, Core Principle, When to Trigger and The Retrospective Process, plus 5 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Codex Retrospective is an agent skill from majiayu000/spellbook. Use when you want Codex to review its own recent history (last N days or specific period) and improve its behavior. Produces minimal, high-signal updates to AGENTS.md and tiny reusable skills. The goal is long-term fluency — Codex gradually becomes better at your specific style, constraints, and workflows.
Its SKILL.md is about 1.6k tokens, which your agent loads only when the skill is triggered. The skill folder holds 6 other files, including reference files (for example `references/agents-md-update-rules.md`, `references/examples/good-retrospective-output.md` and `references/minimal-skill-criteria.md`).
It sits in Product & Project Management, covering Retrospectives and Agent instruction files. The repository describes itself as: Cross-runtime skills for Claude Code, Codex, and multi-agent workflows. The licence is MIT.
When your agent uses it
- You want Codex to review its own recent history (last N days
- Specific period) and improve its behavior
Example prompts
- “/codex-retrospective”
Workflow steps
5 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit ed52af7. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Codex Retrospective loads about 1.6k tokens when it runs, and up to ~3.8k if it reads all its reference files. Until then it costs about 82 tokens; SKILL.md has 835 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from majiayu000/spellbook at commit ed52af7, republished under its MIT licence (© majiayu000). 835 words, ~1,573 tokens.
Download SKILL.mdSave it as
.claude/skills/codex-retrospective/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.- name
- codex-retrospective
- description
- Use when you want Codex to review its own recent history (last N days or specific period) and improve its behavior. Produces minimal, high-signal updates to AGENTS.md and tiny reusable skills. The goal is long-term fluency — Codex gradually becomes better at your specific style, constraints, and workflows.
Codex Retrospective
A structured self-improvement loop for Codex.
This skill turns Codex from a one-off collaborator into a system that gets meaningfully better at working with you over time by systematically eating its own usage history.
Why This Exists
Most people improve their agent usage by manually maintaining AGENTS.md or skills when they notice problems. This skill makes that process deliberate, regular, and high-leverage.
It is directly inspired by strong practices from heavy users (especially Greg Brockman's emphasis on updating the "constitution" from real failures and friction), but executed as a repeatable arsenal-style workflow.
Core Principle
Minimal effective change, grounded in evidence from actual history.
Every output must be:
- The smallest possible useful addition or edit
- Backed by specific patterns observed in recent sessions
- Designed to prevent repetition of the same friction
When to Trigger
- After a painful or repetitive session ("Codex should have known better by now")
- Periodically (weekly or monthly): "Do a retrospective on the last 7/30 days of my Codex usage"
- When
codex-fluentreports that Codex is constantly re-asking for the same context or preferences - After you have manually corrected the same class of mistake multiple times
The Retrospective Process
1. Scope Definition
You specify the time window or focus area:
- "Last 14 days"
- "The three big auth + payments threads from last month"
- "All sessions involving the new Go service"
2. Evidence Collection Preflight
Before proposing any AGENTS.md update or tiny skill, Codex must build a small evidence inventory:
- Scope: repo/project, time window, and focus area.
- Sources checked: current AGENTS.md, relevant existing skills, repo docs, Memories/Chronicle, and local Codex session files when available.
- Evidence handles: session IDs, memory IDs, file paths, PR/issue numbers, or dated incidents that can be checked later.
- Runtime availability: distinguish "skill exists in source" from "skill is installed and triggerable in the active runtime" when that matters.
- No-change path: if evidence is weak, stop with a concise "no high-confidence change" result instead of manufacturing proposals.
Every proposed update must map back to at least one concrete evidence handle.
3. History Analysis (The Skill Guides Codex)
Codex is instructed to look for:
- Recurring mistakes or inefficient patterns
- Things the user had to explain or correct repeatedly
- High-friction moments (lots of back-and-forth, context loss, wrong assumptions)
- Successful patterns worth encoding so they happen by default
- Opportunities to extract tiny, reusable skills
4. Output — Strict Format
The skill forces Codex to produce output in this order:
- Evidence Inventory (scope, sources checked, and concrete handles)
- Retrospective Summary (short, evidence-based)
- Proposed AGENTS.md Updates (exact diff or append text only)
- New or Refined Minimal Skills (at most 1-2 tiny ones, full SKILL.md with frontmatter)
- Rationale + Evidence (which sessions/patterns drove each proposal)
- Application Plan (how to safely apply the changes)
5. Human Gate + Application
You review. The skill then helps you apply the minimal changes cleanly (never blindly overwriting large sections of AGENTS.md).
Show full SKILL.md (356 more words)Show less
Relationship with codex-fluent
These two skills are designed to be used together:
codex-retrospectivefinds behavioral and knowledge improvements (better defaults, new rules, extracted skills).codex-fluentfinds state and context hygiene improvements (session bloat, missing handoffs, archive opportunities).
A good monthly ritual for serious users:
- Run
codex-retrospectiveon the last 30 days. - Run
codex-fluentdiagnosis. - Apply the best changes from both.
Hard Constraints on Output
- Never propose large rewrites of AGENTS.md.
- Never create big new skills. Tiny, focused, high-ROI only.
- Every proposal must reference concrete history ("In the payment retry thread on May 3rd and the similar incident on May 18th...").
- Do not propose changes until the evidence inventory exists and each proposal maps to a concrete handle.
- If nothing high-confidence was found, say so clearly instead of manufacturing improvements.
Gotchas
- Do not turn a single annoying session into a permanent rule unless it was unusually high impact. Prefer "no change" over a weak constitution update.
- Do not rely on memory vibes. Each proposed update needs a concrete session, date range, file, PR, or repeated correction pattern that can be checked.
- Keep generated AGENTS.md text short. If the proposed rule needs multiple paragraphs, it probably belongs in a tiny skill or a project doc instead.
- Application is gated by the user. The retrospective can propose exact diffs, but it must not silently rewrite AGENTS.md or existing skills.
References
references/retrospective-prompt.md— The core prompt template used to drive Codex's self-analysisreferences/agents-md-update-rules.md— Strict rules for what kind of changes are acceptablereferences/minimal-skill-criteria.md— What qualifies as a "tiny useful skill" worth extractingreferences/examples/— Real (sanitized) retrospective outputs and the resulting AGENTS.md diffs
Success Looks Like
After 4–8 weeks of regular use:
- Codex makes fewer basic assumption errors in your domain
- You spend less time re-explaining preferences and constraints
- Your AGENTS.md and skills folder feel like they were written by someone who has worked with you for a long time (because they were)
- New projects ramp up faster because the constitution already encodes hard-won lessons
Start with a focused 7- or 14-day retrospective on a project where you've felt the most friction recently. The pattern will become natural quickly.
© majiayu000, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 4 other files (references) in skills/codex-retrospective of majiayu000/spellbook.
- SKILL.md
- references/agents-md-update-rules.md
- references/examples/good-retrospective-output.md
- references/minimal-skill-criteria.md
- references/retrospective-prompt.md
Open the folder on GitHubat commit ed52af7
Compare with similar skills
Codex Retrospective next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Codex Retrospective this skillmajiayu000/spellbook | 287 | — | ~1.6k | Automated safety check: Pass | MIT | |
| Retrospective Codifymizchi/skills | 360 | — | ~3.2k | Automated safety check: Pass | None | |
| Feature LifecycleInebrio/Routerly | 101 | — | ~3k | Automated safety check: Pass | AGPL-3.0 | |
| Living Docs Governanceqshanx/docs-governance | 137 | — | ~3.7k | Automated safety check: Pass | MIT | |
| Weekly Engineering Retrogarrytan/gstack | 136k | — | ~2.4k | Automated safety check: Pass | MIT | |
| Dough Execute Planterryyin/lizard | 2.5k | — | ~4.3k | Automated safety check: Pass | Custom licence |
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Categories
Questions about Codex Retrospective
What does Codex Retrospective do?
A skill your agent uses when you want Codex to review its own recent history (last N days or specific period) and improve its behavior. Codex Retrospective is an agent skill from majiayu000/spellbook. Use when you want Codex to review its own recent history (last N days or specific period) and improve its behavior.
When should I use Codex Retrospective?
Codex Retrospective fits situations like: you want Codex to review its own recent history (last N days; specific period) and improve its behavior.
How do I install Codex Retrospective in Claude Code?
Run `npx skills add majiayu000/spellbook --skill codex-retrospective -a claude-code`. Or copy the skill folder (skills/codex-retrospective in majiayu000/spellbook) into .claude/skills/codex-retrospective in your project. Claude Code loads it when a task matches its description.
How do I install Codex Retrospective in Codex?
Run `npx skills add majiayu000/spellbook --skill codex-retrospective -a codex`. Or copy the skill folder (skills/codex-retrospective in majiayu000/spellbook) into .agents/skills/codex-retrospective in your project. Codex loads it when a task matches its description.
Can I use Codex Retrospective in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add majiayu000/spellbook --skill codex-retrospective -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/codex-retrospective, .gemini/skills/codex-retrospective, .github/skills/codex-retrospective and .opencode/skills/codex-retrospective in your project.
What does Codex Retrospective need to run?
SKILL.md names no scripts, command-line tools or credentials: Codex Retrospective is instructions for the agent only.
Does Codex Retrospective access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Codex Retrospective safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Codex Retrospective use?
Codex Retrospective is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Codex Retrospective use?
About 1.6k tokens (SKILL.md is roughly 6.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2.3k tokens, read only when the agent opens those files.
What are the alternatives to Codex Retrospective?
Skills that share tags, products or a category with Codex Retrospective: Retrospective Codify (mizchi/skills, 360 stars), Feature Lifecycle (Inebrio/Routerly, 101 stars), Living Docs Governance (qshanx/docs-governance, 137 stars) and Weekly Engineering Retro (garrytan/gstack, 136k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Codex Retrospective?
majiayu000 (a GitHub user) maintains it in majiayu000/spellbook, which has 287 GitHub stars. The repository holds 97 skills in this directory. The repository was last updated on October 8, 2026.
Source: majiayu000/spellbook on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.