Codex CLI Optimizer Skill

Rules and tracking for Codex CLI configuration optimization.

1. Config File Location

Config is managed declaratively via Nix (programs.codex home-manager module).

Source of truth:

• @~/ghq/github.com/i9wa4/dotfiles/nix/home-manager/modules/codex-cli.nix
• @~/ghq/github.com/i9wa4/dotfiles/agents/

Destination	Source	Managed by
~/.codex/config.toml	Generated by activation script	codex-cli.nix
~/.codex/AGENTS.md	agents/AGENTS.md	codex-cli.nix
~/.codex/rules/	agents/rules/	codex-cli.nix
~/.codex/skills/	Multiple flake inputs + local	agent-skills.nix
MCP servers	nix/home-manager/modules/mcp-servers.nix	codex-cli.nix

2. Config Management

Static settings (model, analytics, features, MCP servers) are defined as Nix
attributes in codex-cli.nix. Trusted projects are discovered dynamically
by fd at home-manager switch time and appended to config.toml.

To update settings, edit nix/home-manager/modules/codex-cli.nix and rebuild.

3. Fetch Releases

Use gh command to fetch the latest releases:

FILE=$(mkoutput --dir tmp --label output)
gh api repos/openai/codex/releases --jq '.[0:5]' > "$FILE"
cat "$FILE"

4. CHANGELOG Operations

4.1. Latest Release Summary

1. Fetch releases using the command above
2. Extract the first release entry
3. Categorize changes into:
   • New features (Added)
   • Bug fixes (Fixed)
   • Improvements (Improved/Changed)
   • Breaking changes
4. Present in Japanese with brief explanations

4.2. Version Diff

1. Ask user for start and end versions
2. Extract all releases between those versions
3. Summarize cumulative changes
4. Highlight breaking changes and deprecations

4.3. Breaking Changes Detection

1. Search for keywords: breaking, removed, deprecated,
   changed (behavior changes)
2. List affected commands and options
3. Provide migration guidance

5. Settings Categories

Category	Examples
Model	model, model_reasoning, model_reasoning_effort
Behavior	approval_mode, sandbox, network_access
Display	notify, tui.notifications_method
Shell	shell_environment_commands
History	history, project_doc_max_bytes
Features	features.skills, features.web_search_request
Disable	disable_response_storage, hide_agent_*
Analytics	analytics.enabled, feedback.enabled

6. AGENTS.md Design Guidelines

• YOU MUST: Focus only on persona and core guidelines
• YOU MUST: Keep instructions compatible with both Claude Code and Codex CLI
• NEVER: Include tool-specific syntax (e.g., Claude Code's TodoWrite)

7. Optimization Checklist

Check the following when editing AGENTS.md or config.toml:

• Is the persona definition concise?
• Are basic rules truly needed at all times?
• Can detailed explanations be moved to skills/?
• Is config.toml using appropriate approval_mode?

8. Optimization Tracking

Last reviewed Codex CLI version: v0.104.0 (2026-02-23)

8.1. Applied Optimizations

• AGENTS.md symlinked to CLAUDE.md (shared persona)
• skills/ symlinked to Claude Code skills
• config.common.toml for shared settings

8.2. Pending Considerations

• Create prompts/ symlink to ../claude/commands/ if needed
• Create generate-config.sh for automated config.toml generation
• Evaluate MCP server integration (AWS docs MCP etc.)
• Review tui.notifications_method config option (added in v0.93.0)
• Plan mode (/plan) - now stable and enabled by default (v0.94.0)
• Review smart approvals default behavior (enabled in v0.93.0)
• personality setting - now stable (default: "friendly"); consider
  setting explicitly or using personality = "pragmatic" (v0.94.0)
• AfterToolUse hook - new hook event for post-tool automation (v0.99.0)
• command_attribution = "disable" - co-author attribution disabled
  (v0.103.0)
• approval_policy: on-failure - deprecated; review if used (v0.102.0)
• log_dir config - redirect logs to custom directory (v0.97.0)

8.3. Version Notes

• v0.104.0: WS_PROXY/WSS_PROXY env for websocket proxying,
  ConfigChange hook from app-server, command approval ID plumbing
• v0.103.0: Commit co-author attribution via command_attribution config,
  richer app details in listings
• v0.102.0: Unified permissions flow with TUI history, slash command to grant
  sandbox read access, customizable multi-agent roles, model/rerouted
  notification, approval_policy: on-failure deprecated
• v0.101.0: Bug fixes for memory and model resolution
• v0.100.0: Experimental JS REPL runtime, memory slash commands
  (/m_update, /m_drop), ReadOnlyAccess sandbox policy,
  AfterToolUse hook
• v0.99.0: /statusline command for TUI footer config, shell commands no
  longer interrupt in-flight turns, GIF/WebP image support, AfterToolUse
  hook added, security fix (RUSTSEC-2026-0009)
• v0.98.0: GPT-5.3-Codex model introduced, steer mode stable by default
  (Enter sends, Tab queues)
• v0.97.0: "Allow and remember" for MCP/App tools, live skill updates,
  /debug-config slash command, configurable log_dir
• v0.96.0: unified_exec enabled on all non-Windows platforms
• v0.95.0: ~/.agents/skills personal skill loading, /plan accepts args
  and images, parallel shell tools, CODEX_THREAD_ID env injected
• v0.94.0: Plan mode enabled by default, personality config stable
  (default: friendly), skills from .agents/skills

9. Response Format (CHANGELOG)

# Codex CLI vX.X.X 更新内容

## 新機能
- [機能名]: [説明]

## バグ修正
- [修正内容]

## 改善
- [改善内容]

## 破壊的変更
- [影響を受ける機能と移行方法]

---
Source: https://github.com/openai/codex/releases

10. Important Notes

• Codex CLI changelog is on the releases page, not CHANGELOG.md
• Use GitHub releases API to fetch release notes
• Always specify the version being referenced
• Link to official release page when available

11. Reference Links

• Codex CLI: https://github.com/openai/codex