codex-cli-subagent

This skill lets you spawn a nested Codex process (a “subagent”) using `codex exec` so it can work with the same project and AGENTS.md instructions. ```shell filename="$(openssl rand -hex 4)" codex exec "count the total number of lines of code in this project" 2>>/tmp/${filename}.log ``` In non-interactive mode, `codex exec` runs without a TUI and follows the configured approval/sandbox policy (flags and/or `~/.codex/config.toml`). By default it runs in `read-only` mode, so it cannot edit files or run commands that require network access. When you use this skill, follow these logging rules: - Before running `codex exec`, generate a unique log file name with `openssl rand -hex 4`. - By default, append `2>>/tmp/${filename}.log` to your `codex exec` command so only the subagent’s final message is visible to the caller, while stderr is captured for debugging. - If a run fails, behaves unexpectedly, or the user explicitly asks to see what the inner agent is doing, read the log file (for example: `cat /tmp/${filename}.log`). Since the `codex exec` may run couple hours, set a generous timeout so long-running subagent work can complete: - Use a timeout of at least 60 minutes for the `Run` (or `Bash`) tool unless the user explicitly requests other limit. Use this skill when you want a focused helper agent (for refactors, audits, scripted operations, or scans) while keeping your main session and context intact. Use `codex exec --full-auto` to allow file edits. Use `codex exec --sandbox danger-full-access` to allow edits and networked commands, but only when the user clearly permits this level of access. ### Practical gotchas - Prefer stdin for long prompts to avoid shell quoting/globbing issues: `codex exec - < /tmp/prompt.md`. - If you need built-in web search, pass `--search` (otherwise assume “no web tool” and use `curl`/repo sources). - Don’t run nested subagents (avoid calling `codex exec` from inside a `codex exec` session). - Consider `--output-last-message /tmp/${filename}.out` to capture the final answer without scraping logs. ### Key Flags - `--full-auto`: Unattended operation with workspace-write sandbox - `--dangerously-bypass-approvals-and-sandbox` or `--yolo`: Complete hands-off mode (use carefully) - `--cd <path>`: Set working directory - `--model <model>` or `-m`: Specify model (e.g., `-m gpt-5.1-codex-max`) - `--sandbox`: Sandbox types: - `read-only`: No file edits, no networked commands - `workspace-write`: Can edit files in the workspace - `danger-full-access`: No sandboxing; full access (use with care) - `--search`: Enable built-in web search tool - `--config`: Pass config variables: - `model_reasoning_effort`: Model reasoning effort: `low`, `medium`, `high`; ### Examples ```bash # As a subagent, perform automated refactoring filename="$(openssl rand -hex 4)" codex exec --full-auto "Update all README links to HTTPS" 2>>/tmp/${filename}.log # Run in a specific project directory filename="$(openssl rand -hex 4)" codex exec --cd /path/to/project "Fix failing tests" 2>>/tmp/${filename}.log # Use AGENTS.md context for a focused refactor filename="$(openssl rand -hex 4)" codex exec --cd /path/to/project "Using this repo's AGENTS.md instructions, refactor the test helpers for clarity and consistency" 2>>/tmp/${filename}.log filename="$(openssl rand -hex 4)" codex exec --model gpt-5.1-codex-max --sandbox workspace-write --config model_reasoning_effort=medium - < /tmp/some-big-prompt.md 2>>/tmp/${filename}.log # For audits / deep analysis filename="$(openssl rand -hex 4)" codex exec --model gpt-5.2 --sandbox read-only --config model_reasoning_effort=high "Audit this repo for security issues" 2>>/tmp/${filename}.log ``` ### Input Methods ```bash # Pipe prompt from file filename="$(openssl rand -hex 4)" codex exec - < prompt.txt 2>>/tmp/${filename}.log # Standard input filename="$(openssl rand -hex 4)" echo "Review this code" | codex exec - 2>>/tmp/${filename}.log ``` When this skill is invoked, you should decide: - Whether a subagent is appropriate (e.g., long-running refactor, scan, or analysis). - Which flags, sandbox level, and model to use based on user intent and risk. - For code changes: default to `--model gpt-5.1-codex-max --config model_reasoning_effort=medium` unless the user explicitly requests otherwise. - For audits: default to `--model gpt-5.2 --config model_reasoning_effort=high` unless the user explicitly requests otherwise. - Whether to keep logs suppressed (default: `2>>/tmp/${filename}.log` or read/tail `/tmp/${filename}.log`)