Codex CLI: The Definitive Technical Reference

┌─────────────────────────────────────────────────────────┐
│                    CODEX SURFACES                        │
├─────────────────────────────────────────────────────────┤
│  ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌────────┐ │
│  │   CLI    │  │ Desktop  │  │   IDE    │  │ Cloud  │ │
│  │ Terminal │  │   App    │  │Extension │  │  Tasks │ │
│  └──────────┘  └──────────┘  └──────────┘  └────────┘ │
│  Local exec     Multi-task    Editor-native  Async      │
│  + scripting    + worktrees   + inline edits detached   │
├─────────────────────────────────────────────────────────┤
│  EXTENSION LAYER                                         │
│  ┌─────────┐  ┌─────────┐  ┌─────────┐  ┌─────────┐   │
│  │   MCP   │  │ Skills  │  │  Apps   │  │  Search │   │
│  └─────────┘  └─────────┘  └─────────┘  └─────────┘   │
│  External tools, reusable expertise, ChatGPT            │
│  connectors, web search (cached + live)                  │
├─────────────────────────────────────────────────────────┤
│  SECURITY LAYER                                          │
│  ┌─────────────────────────────────────────────────┐    │
│  │    Sandbox (Seatbelt / Landlock / seccomp)      │    │
│  │    + Approval Policy (untrusted → never)        │    │
│  └─────────────────────────────────────────────────┘    │
│  OS-level filesystem + network restrictions              │
├─────────────────────────────────────────────────────────┤
│  CORE LAYER                                              │
│  ┌─────────────────────────────────────────────────┐    │
│  │         GPT-5.x-Codex Intelligence              │    │
│  │   Tools: Shell, Patch, Read, Web Search         │    │
│  └─────────────────────────────────────────────────┘    │
│  Shared model across all surfaces; costs tokens          │
└─────────────────────────────────────────────────────────┘

# npm (recommended)
npm install -g @openai/codex

# Homebrew (macOS)
brew install --cask codex

# Upgrade to latest
npm install -g @openai/codex@latest

codex login                  # Interactive OAuth (recommended)
codex login --device-auth    # OAuth device code flow (headless)
codex login --with-api-key   # API key from stdin
codex login status           # Check auth state (exit 0 = logged in)
codex logout                 # Clear stored credentials

# Generate completions for your shell
codex completion bash > /etc/bash_completion.d/codex
codex completion zsh > ~/.zsh/completions/_codex
codex completion fish > ~/.config/fish/completions/codex.fish

codex --version
# Codex CLI v0.101.0

codex                        # Launch TUI
codex "fix the failing tests" # Launch with initial prompt
codex -m gpt-5.3-codex      # Specify model
codex --full-auto            # Workspace-write sandbox + on-request approval

codex app                    # Launch desktop app (auto-installs if missing)

codex cloud list             # List recent cloud tasks
codex apply <TASK_ID>        # Apply diff from a specific cloud task

# ~/.codex/config.toml — annotated reference

# ─── Model Selection ───────────────────────────────────
model = "gpt-5.3-codex"                # Default model (272K context)
model_provider = "openai"               # Provider (openai, oss, or custom provider id)
model_reasoning_effort = "medium"       # low|medium|high|xhigh (model-dependent)
model_reasoning_summary = "auto"        # auto|concise|detailed|none
model_verbosity = "medium"              # low|medium|high
personality = "pragmatic"               # none|friendly|pragmatic
review_model = "gpt-5.2-codex"         # Model for /review command
oss_provider = "lmstudio"              # lmstudio|ollama (used with --oss)

# ─── Sandbox & Approval ───────────────────────────────
sandbox_mode = "workspace-write"        # read-only|workspace-write|danger-full-access
approval_policy = "on-request"          # untrusted|on-failure|on-request|never

[sandbox_workspace_write]
writable_roots = []                     # Additional writable paths
network_access = false                  # Allow outbound network
exclude_tmpdir_env_var = false          # Exclude $TMPDIR from sandbox
exclude_slash_tmp = false               # Exclude /tmp from sandbox

# ─── Web Search ────────────────────────────────────────
web_search = "live"                     # Web search mode (constrained by allowed modes)

# ─── Instructions ──────────────────────────────────────
developer_instructions = ""             # Additional injected instructions
model_instructions_file = ""            # Custom instructions file path
compact_prompt = ""                     # Custom history compaction prompt

# ─── Shell Environment ─────────────────────────────────
[shell_environment_policy]
inherit = "all"                         # all|core|none
ignore_default_excludes = false         # Set true to keep KEY/SECRET/TOKEN vars
exclude = []                            # Glob patterns to exclude
set = {}                                # Explicit overrides
include_only = []                       # Whitelist patterns

# ─── Authentication ────────────────────────────────────
cli_auth_credentials_store = "file"     # file|keyring|auto
forced_login_method = "chatgpt"         # chatgpt|api

# ─── History & Storage ─────────────────────────────────
[history]
persistence = "save-all"                # save-all|none
max_bytes = 0                           # Cap size (0 = unlimited)

tool_output_token_limit = 10000         # Max tokens per tool output
log_dir = ""                            # Custom log directory

# ─── UI & Display ──────────────────────────────────────
file_opener = "vscode"                  # vscode|vscode-insiders|windsurf|cursor|none
hide_agent_reasoning = false
show_raw_agent_reasoning = false
check_for_update_on_startup = true

[tui]
notifications = false                   # Enable notifications
notification_method = "auto"            # auto|osc9|bel
animations = true
show_tooltips = true
alternate_screen = "auto"               # auto|always|never
status_line = ["model", "context-remaining", "git-branch"]

# ─── Project Trust ─────────────────────────────────────
project_doc_max_bytes = 32768           # Max AGENTS.md size (32 KiB)
project_doc_fallback_filenames = []     # Alternative instruction filenames
project_root_markers = [".git"]         # Project root detection

# ─── Feature Flags ─────────────────────────────────────
# Use `codex features list` for current names/stages/defaults.
[features]
shell_tool = true                       # Shell command execution (stable)
collaboration_modes = true              # Plan mode (stable)
personality = true                      # Personality selection (stable)
request_rule = true                     # Smart approvals (stable)
unified_exec = true                     # PTY-backed exec (stable)
shell_snapshot = true                   # Shell env snapshots (stable)
remote_models = true                    # Refresh remote model list (stable)
apps = false                            # ChatGPT Apps/connectors (experimental)
child_agents_md = false                 # AGENTS.md guidance (experimental)
runtime_metrics = false                 # Runtime summary in turns

# ─── Project Trust ─────────────────────────────────────
[projects."/absolute/path/to/repo"]
trust_level = "trusted"                 # Per-project trust override

# Define profiles in ~/.codex/config.toml

[profiles.fast]
model = "gpt-5.1-codex-mini"
model_reasoning_effort = "low"
approval_policy = "on-request"
sandbox_mode = "workspace-write"
personality = "pragmatic"

[profiles.careful]
model = "gpt-5.3-codex"
model_reasoning_effort = "xhigh"
approval_policy = "untrusted"
sandbox_mode = "read-only"

[profiles.auto]
model = "gpt-5.3-codex"
model_reasoning_effort = "medium"
approval_policy = "never"
sandbox_mode = "workspace-write"

codex --profile fast "quick refactor"
codex --profile careful "security audit"
codex -p auto "fix CI"

[model_providers.azure]
name = "Azure OpenAI"
base_url = "https://YOUR_PROJECT.openai.azure.com/openai"
wire_api = "responses"
query_params = { api-version = "2025-04-01-preview" }
env_key = "AZURE_OPENAI_API_KEY"

[model_providers.ollama]
name = "Ollama (Local)"
base_url = "http://localhost:11434/v1"
wire_api = "chat"

codex --oss "explain this function"               # Uses default OSS provider
codex --oss --local-provider lmstudio "explain"   # Explicit LM Studio
codex --oss --local-provider ollama "explain"      # Explicit Ollama

model_provider = "oss"
oss_provider = "lmstudio"   # or "ollama"

codex -c model="gpt-5.2-codex" "refactor the API"
codex -c 'sandbox_workspace_write.network_access=true' "install dependencies"
codex -c model_reasoning_effort="xhigh" "debug the race condition"

Is this a quick fix or simple question?
├─ Yes → gpt-5.1-codex-mini (fastest, cheapest)
└─ No
   ├─ Do you need real-time pairing speed?
   │  ├─ Yes → gpt-5.3-codex-spark (interactive, lower latency)
   │  └─ No
   │     ├─ Is this a multi-file refactor or migration?
   │     │  ├─ Yes → gpt-5.2-codex (272K context, strong at long tasks)
   │     │  └─ No → gpt-5.3-codex (default, best overall)
   └─ Still unsure? → gpt-5.3-codex

codex -c model_reasoning_effort="xhigh" "find the race condition"

codex -m gpt-5.3-codex-spark "pair with me on this component"

codex --sandbox workspace-write --ask-for-approval on-request

sandbox_mode = "workspace-write"
approval_policy = "on-request"

sandbox_mode = "danger-full-access"
approval_policy = "untrusted"

sandbox_mode = "workspace-write"
approval_policy = "never"

# Per-run
codex -c 'sandbox_workspace_write.network_access=true' "install the packages"

# In config.toml
[sandbox_workspace_write]
network_access = true
writable_roots = ["/path/to/extra/dir"]   # Additional writable directories
exclude_slash_tmp = false                  # Prevent /tmp from being writable
exclude_tmpdir_env_var = false             # Prevent $TMPDIR from being writable

codex sandbox macos --full-auto -- ls /etc/passwd   # macOS test
codex sandbox linux --full-auto -- cat /etc/shadow   # Linux test

~/.codex/AGENTS.md                     ← Global defaults
  └─ /repo/AGENTS.md                   ← Project-wide rules
      └─ /repo/services/AGENTS.md      ← Service-specific rules
          └─ /repo/services/payments/
               AGENTS.override.md      ← Overrides everything above for this dir

# Repository Guidelines

## Build, Test, and Development Commands
- Run API (dev): `python3 -m uvicorn main:app --reload`
- Install deps: `pip install -r requirements.txt`
- Lint: `python3 -m ruff check .` (auto-fix: `--fix`)
- Format: `python3 -m ruff format .`
- Tests: `python3 -m pytest -v`
- Coverage: `python3 -m pytest --cov=app --cov-report=term-missing`

## Coding Style & Naming Conventions
- Python 3.11+. Type hints on all functions.
- Ruff enforced: 88-char lines, double quotes, spaces for indent.
- Naming: modules `snake_case.py`, classes `PascalCase`, functions `snake_case`.

## Commit & Pull Request Guidelines
- Conventional Commits: `feat:`, `fix:`, `docs:`, `refactor:`, `chore:`, `test:`
- Commits should be small and focused.
- PRs must include: description, test plan, and screenshots for UI changes.

## Security
- Never commit secrets. Use `.env` for local config.
- Validate all external API calls with proper error handling.

# Custom fallback filenames (in addition to AGENTS.md)
project_doc_fallback_filenames = ["TEAM_GUIDE.md", ".agents.md"]

# Increase max size for large instruction files
project_doc_max_bytes = 65536    # 64 KiB (default: 32 KiB)

codex                           # Launch TUI
/init                           # Generate AGENTS.md scaffold

codex --ask-for-approval never "Summarize your current instructions"

# In ~/.codex/config.toml or .codex/config.toml

[mcp_servers.context7]
enabled = true
required = true                         # Fail startup if unavailable
command = "npx"
args = ["-y", "@upstash/context7-mcp"]
env = { "MY_VAR" = "value" }            # Static env vars
env_vars = ["PATH", "HOME"]             # Forward host env vars
cwd = "/path/to/project"                # Optional working directory
startup_timeout_sec = 10
tool_timeout_sec = 60
enabled_tools = ["search", "summarize"]  # Tool allowlist
disabled_tools = ["slow-tool"]           # Tool denylist

[mcp_servers.figma]
enabled = true
url = "https://mcp.figma.com/mcp"
bearer_token_env_var = "FIGMA_OAUTH_TOKEN"
http_headers = { "X-Figma-Region" = "us-east-1" }
env_http_headers = { "X-Org-Id" = "FIGMA_ORG_ID" }  # Headers from env vars
startup_timeout_sec = 10
tool_timeout_sec = 60

codex mcp add context7 -- npx -y @upstash/context7-mcp
codex mcp add context7 --env API_KEY=... -- npx -y @upstash/context7-mcp   # With env vars
codex mcp add figma --url https://mcp.figma.com/mcp --bearer-token-env-var FIGMA_OAUTH_TOKEN
codex mcp list                          # List all configured servers
codex mcp list --json                   # JSON output
codex mcp get context7                  # Show server config
codex mcp get context7 --json           # JSON output
codex mcp login <server>                # OAuth flow for HTTP servers
codex mcp logout <server>               # Remove OAuth credentials
codex mcp remove <server>               # Delete server definition

codex mcp-server                        # Start as MCP server (stdio transport)

from agents import Agent, Runner
from agents.mcp import MCPServerStdio

async with MCPServerStdio(
    name="Codex CLI",
    params={"command": "npx", "args": ["-y", "codex", "mcp-server"]},
    client_session_timeout_seconds=360000,
) as codex_mcp_server:
    agent = Agent(name="Developer", mcp_servers=[codex_mcp_server])
    result = await Runner.run(agent, "Fix the failing tests")

my-skill/
  SKILL.md           (required — instructions)
  scripts/           (optional — executable scripts)
  references/        (optional — reference docs)
  assets/            (optional — images, icons)
  agents/openai.yaml (optional — metadata, UI, dependencies)

---
name: security-audit
description: Run a comprehensive security audit on the codebase.
---

## 보안 감사 절차

1. `rg -i "(api_key|password|secret|token)\s*=" --type py`를 사용하여 하드코딩된 시크릿을 스캔합니다
2. SQL 인젝션 확인: 쿼리에서 문자열 보간을 검토합니다
3. 모든 API 엔드포인트에서 입력 유효성 검사를 확인합니다
4. 의존성 취약점 확인: `pip audit` 또는 `npm audit`
5. 인증 및 인가 패턴을 검토합니다
6. 심각도 수준(Critical/High/Medium/Low)과 함께 결과를 보고합니다

interface:
  display_name: "Security Audit"
  short_description: "Comprehensive codebase security review"
  icon_small: "./assets/shield.svg"
  brand_color: "#DC2626"
  default_prompt: "Run a security audit on this repository"

policy:
  allow_implicit_invocation: false    # Require explicit $skill

dependencies:
  tools:
    - type: "mcp"
      value: "snyk"
      transport: "streamable_http"
      url: "https://mcp.snyk.io/mcp"

[[skills.config]]
path = "/path/to/skill/SKILL.md"
enabled = false

/plan                              # Switch to plan mode
/plan "redesign the API layer"     # Plan mode with initial prompt

/fork                              # Fork current conversation
/fork "try a different approach"   # Fork with new prompt

codex exec "summarize the repository structure"
codex exec --full-auto "fix the CI failure"
codex exec --json "triage open bugs" -o result.txt

codex exec --json "fix the tests" | jq

{"type":"thread.started","thread_id":"019c5c94-..."}
{"type":"turn.started"}
{"type":"item.started","item":{"id":"item_1","type":"command_execution","status":"in_progress"}}
{"type":"item.completed","item":{"id":"item_3","type":"agent_message","text":"..."}}
{"type":"turn.completed","usage":{"input_tokens":24763,"cached_input_tokens":24448,"output_tokens":122}}

codex exec "Extract project metadata" \
  --output-schema ./schema.json \
  -o ./project-metadata.json

codex exec resume --last "continue where you left off"
codex exec resume <SESSION_ID> "fix the remaining issues"
codex exec review --base main           # Code review against a branch

Allowed domains: pypi.org, npmjs.com, github.com
Allowed methods: GET, HEAD, OPTIONS

codex cloud exec --env <ENV_ID> "Fix failing tests"  # Start a cloud task
codex cloud status <TASK_ID>                          # Check task progress
codex cloud diff <TASK_ID>                            # View task diff
codex cloud list                                      # List recent tasks
codex cloud list --json                               # JSON output
codex cloud apply <TASK_ID>                           # Apply from cloud subcommand
codex apply <TASK_ID>                                 # Apply diff (top-level shortcut)

codex app                      # Auto-downloads and installs on first run

# .github/workflows/codex.yml
name: Codex
on:
  pull_request:
    types: [opened]

jobs:
  codex:
    runs-on: ubuntu-latest
    outputs:
      final_message: ${{ steps.run_codex.outputs.final-message }}
    steps:
      - uses: actions/checkout@v5
      - name: Run Codex
        id: run_codex
        uses: openai/codex-action@v1
        with:
          openai-api-key: ${{ secrets.OPENAI_API_KEY }}
          prompt-file: .github/codex/prompts/review.md
          sandbox: workspace-write
          safety-strategy: drop-sudo

with:
  allow-users: "admin,maintainer"     # Limit who can trigger
  allow-bots: false                   # Block bot-triggered runs

npm install @openai/codex-sdk

import { Codex } from "@openai/codex-sdk";

const codex = new Codex();
const thread = codex.startThread();

// Multi-turn conversation
const turn1 = await thread.run("Diagnose CI failures and propose a fix");
console.log(turn1.finalResponse);

const turn2 = await thread.run("Implement the fix and add tests");
console.log(turn2.items);

// Resume a previous session
const resumed = codex.resumeThread("<thread-id>");
await resumed.run("Continue from previous work");

// Custom working directory, skip git check
const thread = codex.startThread({
  workingDirectory: "/path/to/project",
  skipGitRepoCheck: true,
});

// Custom environment and config overrides
const codex = new Codex({
  env: { CODEX_API_KEY: process.env.MY_KEY },
  config: { model: "gpt-5.2-codex" },
});

codex --version                        # Check CLI version
codex login status                     # Verify authentication
codex mcp list                         # Check MCP server status
codex debug app-server --help          # Debug app server issues

/status                                # Token/session overview
/config                                # Inspect effective config values and sources
/compact                               # Summarize history to reclaim context

npm uninstall -g @openai/codex && npm install -g @openai/codex@latest

codex debug app-server send-message-v2  # Test app-server client

/feedback                              # Send logs to Codex maintainers (in TUI)

# /etc/codex/managed-admin-config.toml

model_reasoning_effort = "high"
model_reasoning_summary = "auto"
model = "gpt-5.3-codex"

require_approval = "untrusted"
require_sandbox = "workspace-write"

╔═══════════════════════════════════════════════════════════════╗
║                    CODEX CLI QUICK REFERENCE                  ║
╠═══════════════════════════════════════════════════════════════╣
║                                                               ║
║  LAUNCH                                                       ║
║  codex                      Interactive TUI                   ║
║  codex "prompt"             TUI with initial prompt           ║
║  codex exec "prompt"        Non-interactive mode              ║
║  codex app                  Desktop app                       ║
║  codex resume               Resume previous session           ║
║  codex fork                 Fork a session                    ║
║                                                               ║
║  FLAGS                                                        ║
║  -m, --model <model>        Select model                      ║
║  -p, --profile <name>       Load config profile               ║
║  -s, --sandbox <mode>       Sandbox mode                      ║
║  -C, --cd <dir>             Working directory                 ║
║  -i, --image <file>         Attach image(s)                   ║
║  -c, --config <key=value>   Override config                   ║
║  --full-auto                workspace-write + on-request      ║
║  --oss                      Use local models (Ollama)         ║
║  --search                   Enable live web search            ║
║                                                               ║
║  SLASH COMMANDS (in TUI)                                      ║
║  /compact      Free tokens   /diff        Git diff            ║
║  /review       Code review   /plan        Plan mode           ║
║  /model        Switch model  /status      Session info        ║
║  /fork         Fork thread   /init        AGENTS.md scaffold  ║
║  /mcp          MCP tools     /skills      Invoke skills       ║
║  /ps           Background    /personality Style               ║
║  /permissions  Approval mode /statusline  Footer config       ║
║                                                               ║
║  TUI SHORTCUTS                                                ║
║  @              Fuzzy file search                             ║
║  !command       Run shell command                             ║
║  Ctrl+G         External editor                               ║
║  Enter          Inject instructions (while running)           ║
║  Esc Esc        Edit previous messages                        ║
║                                                               ║
║  EXEC MODE (CI/CD)                                            ║
║  codex exec --full-auto "task"          Sandboxed auto        ║
║  codex exec --json -o out.txt "task"    JSON + file output    ║
║  codex exec --output-schema s.json      Structured output     ║
║  codex exec resume --last "continue"    Resume session        ║
║                                                               ║
║  MCP MANAGEMENT [experimental]                                ║
║  codex mcp add <name> -- <cmd>    Add STDIO server            ║
║  codex mcp add <name> --url <u>   Add HTTP server             ║
║  codex mcp list                    List servers                ║
║  codex mcp login <name>           OAuth flow                  ║
║  codex mcp remove <name>          Delete server               ║
║                                                               ║
║  CLOUD [EXPERIMENTAL]                                         ║
║  codex cloud exec --env <ID> Start cloud task                 ║
║  codex cloud status <ID>     Check task progress              ║
║  codex cloud diff <ID>       View task diff                   ║
║  codex cloud list            List tasks                       ║
║  codex apply <TASK_ID>       Apply cloud diff locally         ║
║                                                               ║
║  CONFIG FILES                                                 ║
║  ~/.codex/config.toml        User config                      ║
║  .codex/config.toml          Project config                   ║
║  ~/.codex/AGENTS.md          Global instructions              ║
║  AGENTS.md                   Project instructions             ║
║  managed-admin-config.toml   Enterprise policy constraints    ║
║                                                               ║
║  SANDBOX MODES                                                ║
║  read-only          Read files only, no mutations             ║
║  workspace-write    Read/write in workspace + /tmp            ║
║  danger-full-access Full machine access                       ║
║                                                               ║
║  APPROVAL POLICIES                                            ║
║  untrusted     Prompt for all mutations                       ║
║  on-failure    Auto-run until failure                         ║
║  on-request    Prompt for boundary violations                 ║
║  never         No prompts                                     ║
║                                                               ║
║  MODELS (Feb 2026)                                            ║
║  gpt-5.3-codex         Default flagship (272K)               ║
║  gpt-5.3-codex-spark   Interactive, lower latency (128K)     ║
║  gpt-5.2-codex         Long-horizon refactors (272K)         ║
║  gpt-5.1-codex-mini    Quick tasks, cost-efficient (272K)    ║
║                                                               ║
╚═══════════════════════════════════════════════════════════════╝