| name | codex |
| description | Use when user wants to delegate a task to OpenAI Codex CLI. Triggers on "ask codex", "have codex", "codex:", "send to codex", "let codex", "run codex". Delegates via subagent to keep main context clean. |
Codex Delegation
Delegate tasks to OpenAI's Codex CLI via a subagent. Codex runs non-interactively and results are summarized back.
Routing
Is this a code review request?
│
┌────┴────┐
yes no
│ │
▼ ▼
codex codex exec
review --sandbox read-only
Execution
Dispatch a single Bash subagent (Task tool) with the appropriate command. This keeps all Codex output isolated from the main context window.
For code reviews
Use codex review which has specialized review behavior:
Task tool:
subagent_type: Bash
model: haiku
description: "Codex review"
prompt: |
Run this command and return the full output:
codex review {FLAGS} "{INSTRUCTIONS}" -o /tmp/codex-out.txt 2>/dev/null; cat /tmp/codex-out.txt
Flags:
- --uncommitted → review staged/unstaged/untracked changes
- --base BRANCH → review changes against a base branch
- --commit SHA → review a specific commit
Default to --uncommitted if user didn't specify.
Return the complete review output.
For everything else
Use codex exec in read-only sandbox:
Task tool:
subagent_type: Bash
model: haiku
description: "Codex: {brief task}"
prompt: |
Run this command and return the full output:
codex exec "{USER_PROMPT}" --sandbox read-only -C "{WORKING_DIR}" -o /tmp/codex-out.txt 2>/dev/null; cat /tmp/codex-out.txt
Return the complete output.
If user wants Codex to make changes
User must explicitly ask for write access. Use --sandbox workspace-write instead of read-only:
codex exec "{PROMPT}" --sandbox workspace-write -C "{WORKING_DIR}" -o /tmp/codex-out.txt 2>/dev/null; cat /tmp/codex-out.txt
After Subagent Returns
- Read the subagent's output
- Present a concise summary to the user
- Include key findings, recommendations, or answers
- Mention if Codex flagged any critical issues (P0/P1)
Quick Reference
| User Says | Route To | Flags |
|---|
| "ask codex to review" | codex review | --uncommitted |
| "codex review against main" | codex review | --base main |
| "codex review commit abc123" | codex review | --commit abc123 |
| "ask codex to analyze/explain/plan" | codex exec | --sandbox read-only |
| "have codex fix/refactor/implement" | codex exec | --sandbox workspace-write |
Common Mistakes
| Mistake | Fix |
|---|
| Running codex in main context | Always use a Bash subagent via Task tool |
Forgetting 2>/dev/null | Codex thinking tokens flood context without this |
Forgetting -o flag | Without it, output mixes with metadata noise |
| Using interactive mode | Always use codex exec or codex review, never bare codex |
| Hardcoding model | Let user's codex config choose the model |
