feat(setup): add Codex CLI setup recipe (#1243)

* Add Codex setup recipe

* Sync beads issues (bd-1zo)

---------

Co-authored-by: Amp <amp@example.com>

docs/CLI_REFERENCE.md

@@ -766,18 +766,21 @@ bd sync  # Force immediate sync, bypass debounce
 ```bash
 # Setup editor integration (choose based on your editor)
 bd setup factory  # Factory.ai Droid - creates/updates AGENTS.md (universal standard)
+bd setup codex    # Codex CLI - creates/updates AGENTS.md
 bd setup claude   # Claude Code - installs SessionStart/PreCompact hooks
 bd setup cursor   # Cursor IDE - creates .cursor/rules/beads.mdc
 bd setup aider    # Aider - creates .aider.conf.yml
 
 # Check if integration is installed
 bd setup factory --check
+bd setup codex --check
 bd setup claude --check
 bd setup cursor --check
 bd setup aider --check
 
 # Remove integration
 bd setup factory --remove
+bd setup codex --remove
 bd setup claude --remove
 bd setup cursor --remove
 bd setup aider --remove
@@ -792,6 +795,7 @@ bd setup claude --stealth    # Use stealth mode (flush only, no git operations)
 
 **What each setup does:**
 - **Factory.ai** (`bd setup factory`): Creates or updates AGENTS.md with beads workflow instructions (works with multiple AI tools using the AGENTS.md standard)
+- **Codex CLI** (`bd setup codex`): Creates or updates AGENTS.md with beads workflow instructions for Codex
 - **Claude Code** (`bd setup claude`): Adds hooks to Claude Code's settings.json that run `bd prime` on SessionStart and PreCompact events
 - **Cursor** (`bd setup cursor`): Creates `.cursor/rules/beads.mdc` with workflow instructions
 - **Aider** (`bd setup aider`): Creates `.aider.conf.yml` with bd workflow instructions

docs/INSTALLING.md

@@ -189,6 +189,7 @@ bd init --quiet
 bd setup claude   # Claude Code - installs SessionStart/PreCompact hooks
 bd setup cursor   # Cursor IDE - creates .cursor/rules/beads.mdc
 bd setup aider    # Aider - creates .aider.conf.yml
+bd setup codex    # Codex CLI - creates/updates AGENTS.md
 ```
 
 **How it works:**
@@ -208,6 +209,7 @@ bd setup aider    # Aider - creates .aider.conf.yml
 bd setup claude --check   # Check Claude Code integration
 bd setup cursor --check   # Check Cursor integration
 bd setup aider --check    # Check Aider integration
+bd setup codex --check    # Check Codex integration
 ```
 
 ### Claude Code Plugin (Optional)

docs/SETUP.md

@@ -18,6 +18,7 @@ The `bd setup` command uses a **recipe-based architecture** to configure beads i
 | `claude` | `~/.claude/settings.json` | SessionStart/PreCompact hooks |
 | `gemini` | `~/.gemini/settings.json` | SessionStart/PreCompress hooks |
 | `factory` | `AGENTS.md` | Marked section |
+| `codex` | `AGENTS.md` | Marked section |
 | `aider` | `.aider.conf.yml` + `.aider/` | Multi-file config |
 
 ## Quick Start
@@ -33,6 +34,7 @@ bd setup kilocode   # Kilo Code
 bd setup claude     # Claude Code
 bd setup gemini     # Gemini CLI
 bd setup factory    # Factory.ai Droid
+bd setup codex      # Codex CLI
 bd setup aider      # Aider
 
 # Verify installation
@@ -139,6 +141,24 @@ If you already have an AGENTS.md file with other project instructions:
 
 You can use multiple integrations simultaneously - they complement each other!
 
+## Codex CLI
+
+Codex reads `AGENTS.md` instructions at the start of each run/session. Adding the beads section is enough to get Codex and beads working together.
+
+### Installation
+
+```bash
+bd setup codex
+```
+
+### What Gets Installed
+
+Creates or updates `AGENTS.md` with the beads integration section (same markers as Factory.ai).
+
+### Notes
+
+- Restart Codex if it's already running to pick up the new instructions.
+
 ## Claude Code
 
 Claude Code integration uses hooks to automatically inject beads workflow context at session start and before context compaction.