OpenAI Codex CLI

npx shibbo init codex

What it writes

Rules go into AGENTS.md, which Codex reads natively, one file per directory from the repo root down.

MCP, in .codex/config.toml:

[mcp_servers.shibbo]
command = "npx"
args = ["shibbo", "mcp"]

Or for your user: codex mcp add shibbo -- npx shibbo mcp.

Hook, in .codex/hooks.json:

{
  "hooks": {
    "PostToolUse": [
      { "matcher": "apply_patch", "hooks": [{ "type": "command", "command": "npx shibbo hook post-edit --for codex", "timeout": 30 }] }
    ]
  }
}

How it works

Codex edits files through apply_patch, and the hook receives the patch text instead of a file path. Shibbo reads the paths from the patch's *** Update File: and *** Add File: lines, checks those files, and sends hits inside the added lines back as hookSpecificOutput.additionalContext.

Caveats

• Project hooks and .codex/config.toml load only in trusted projects; approve the hook once in /hooks.
• The patch header format isn't spelled out on the hooks page. If a future version changes it, the hook goes quiet and never misreports.

Sources: AGENTS.md, MCP, hooks.