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OpenAI / ChatGPT Guide Hub

Codex CLI vs Claude Code — Practical Comparison

This page is the comparison section of the "OpenAI Codex CLI Complete Guide". For onboarding, see Overview and Quick Start; for operations, see Best Practices.

Essential Differences (Summary)

  • Permission model differences
  • Codex CLI: Read Only / Auto / Full Access. Auto allows automatic local edits and execution, requires approval for out-of-scope access and network. Full Access skips approval (use with caution).
  • Claude Code: default / acceptEdits / plan / bypassPermissions. plan is analysis only, bypassPermissions skips approval (assumes isolation).
  • Sandbox/safety measures
  • Codex CLI: macOS: Seatbelt / Linux: Landlock+seccomp. Limitations exist on WSL/containers.
  • Claude Code: Writes restricted to launch directory, Bash/network require approval, dangerous commands are blocked, among other multi-layered protections.
  • Model/authentication
  • Codex: GPT-5-Codex (released January 2025, 7-hour autonomous operation) / GPT-5 recommended (switch with /model). ChatGPT sign-in or API key.
  • Claude: Claude Sonnet series. Operates via Claude.ai/Anthropic API/Bedrock/Vertex.
  • IDE/ecosystem
  • Codex: CLI-centric (separate Codex IDE / Cloud line available).
  • Claude: VS Code/JetBrains integration, MCP/Actions/admin features and rich peripherals.

Simple Comparison Table

AspectCodex CLI (OpenAI)Claude Code (Anthropic)
Permission modeRead Only / Auto / Full Access. Auto for local edits/execution, network/external requires approval. Full Access bypasses approval (caution).default / acceptEdits / plan / bypassPermissions. plan is analysis-only, bypassPermissions skips approval (assumes isolation).
SandboxSeatbelt (macOS) / Landlock+seccomp. Limitations on WSL/containers.Writes restricted to launch directory, Bash/network require approval, dangerous commands blocked/warned.
NetworkRestricted by default. Approval required when needed (Cloud: allowed domains/HTTP controls).Approval-based (WebFetch, etc.).
Recommended modelGPT-5-Codex (7-hour autonomous support) / GPT-5 (switch with /model)Claude Sonnet series (3.7/4, etc.)
Auth/onboardingChatGPT sign-in or API key. Windows: WSL recommended.Claude.ai/Anthropic API/Bedrock/Vertex. SSO/policy distribution available.
IDE/extensionsCLI-centric (Codex IDE/Cloud is separate line). MCP support.IDE integration, MCP, Hooks/Slash/Actions and admin/automation.
Non-interactive/CIcodex exec for headless execution.-p (print) + --max-turns, etc. for headless operation.
PricingChatGPT integration: no additional API charges (limits per plan). API: MTok-based metering.API: MTok-based metering. Consumer plans have limits/fair use.

Note: "Local execution" does not mean "code never leaves your machine." Both tools may send diffs/excerpts needed for inference. Exclusion of sensitive data and thorough approval workflows are prerequisites.

How to Choose in Practice (Guidelines)

  • Incremental changes/diff-focused/CI-oriented → Codex CLI
  • Planning/long-form/IDE integration-focused → Claude Code
  • Strict permission management/approval visibility → Codex CLI
  • Enterprise governance/distribution/integrated operations → Claude Code