Codex CLI

OpenAI's terminal coding agent. Reads, edits, and runs code locally with configurable sandbox and approval controls. Built in Rust, open source.

Quick Reference

```bash

Interactive session

codex "your prompt here"

Non-interactive (scripting/CI)

codex exec "your prompt here" codex exec --json "prompt" # JSONL output codex exec -o result.txt "prompt" # Save last message

Code review

codex review # Review current branch vs main codex review --uncommitted # Review all uncommitted changes codex review --base develop # Review against specific branch codex review --commit abc123 # Review a specific commit

Session management

codex resume # Pick from recent sessions codex resume --last # Continue most recent codex fork --last # Fork most recent into new thread

Cloud tasks (experimental)

codex cloud exec --env ENV_ID "task" codex cloud list codex cloud apply TASK_ID codex cloud diff TASK_ID ```

Key Flags

Flag	Short	Purpose
`--model`	`-m`	Select model (e.g. `gpt-5.3-codex`, `o3`)
`--sandbox`	`-s`	`read-only` / `workspace-write` / `danger-full-access`
`--ask-for-approval`	`-a`	`untrusted` / `on-failure` / `on-request` / `never`
`--full-auto`		Shortcut: `-a on-request -s workspace-write`
`--image`	`-i`	Attach image(s) to prompt
`--search`		Enable live web search
`--cd`	`-C`	Set the working directory for the `codex` command. This directory will be used as the base for operations by subcommands like `exec`, `review`, `cloud exec`, etc. This flag should be passed directly to the `codex` command. For example: `codex --cd /path/to/project review`.
`--add-dir`		Grant additional writable directories
`--config`	`-c`	Override config value (e.g. `-c model="o3"`)
`--profile`	`-p`	Load named config profile
`--oss`		Use local model provider (LM Studio / Ollama)
`--json`		(exec only) JSONL output
`--output-last-message`	`-o`	(exec only) Write last message to file
`--yolo`		Bypass all approvals and sandbox (DANGEROUS)

Approval Modes

• untrusted (default): Only trusted commands (ls, cat, sed…) run without asking. Others prompt user.
• on-failure: Run all commands freely. Only prompt if a command fails.
• on-request: Model decides when to ask.
• never: Never prompt. Failures go straight back to model.

Sandbox Modes

• read-only: No file writes, no network.
• workspace-write: Write only in workspace + specified dirs. Configurable network access.
• danger-full-access: Unrestricted. Use only in isolated environments.

Slash Commands (Interactive)

Command	Purpose
`/model`	Switch model mid-session
`/permissions`	Adjust approval/sandbox settings
`/review`	Run code review
`/diff`	Show git diff including untracked files
`/compact`	Summarize conversation to free tokens
`/mention`	Attach file to conversation
`/new`	Start new conversation in same session
`/resume`	Resume saved conversation
`/fork`	Fork current conversation
`/init`	Generate AGENTS.md scaffold
`/mcp`	List MCP tools
`/status`	Show session config and token usage
`/ps`	Show background terminals
`/quit`	Exit

Common Patterns

CI/CD Automation

```bash

Run task non-interactively with JSON output

codex exec --json --full-auto "fix all lint errors" | process_results.sh

Structured output with schema

codex exec --output-schema schema.json "analyze this codebase" ```

Code Review in CI

```bash codex review --base main --title "PR #42: Add auth" ```

Multi-Directory Projects

```bash codex --cd ./backend --add-dir ./shared "update the API" ```

Image-Driven Development

```bash codex -i mockup.png "implement this UI exactly" ```

Local OSS Models

```bash codex --oss --CPA ollama -m codellama "refactor this function" ```

Configuration

Config file: `~/.codex/config.toml` (user-level), `.codex/config.toml` (project-level).

For full configuration reference including all keys, MCP server setup, model providers, sandbox permissions, shell environment policies, and OpenTelemetry: see references/config-reference.md.

MCP Server Management

```bash codex mcp list # List configured servers codex mcp add # Add MCP server codex mcp remove # Remove MCP server codex mcp login # Authenticate with server codex mcp logout # Remove server credentials ```

Configure in config.toml:

```toml [mcp_servers.my-server] command = "npx" args = ["-y", "@my/mcp-server"] enabled = true ```