Codex CLI vs Claude Code: OpenAI vs Anthropic Terminal Coding Agents
A comprehensive comparison between OpenAI's Codex CLI and Anthropic's Claude Code. Discover how these two AI giants' terminal-based coding agents stack up against each other.
Codex CLI vs Claude Code: OpenAI vs Anthropic Terminal Coding Agents
The two leading AI labs have both released terminal-based coding agents: Codex CLI from OpenAI, built in Rust and powered by GPT-5-Codex, versus Claude Code from Anthropic, featuring checkpoint rollback and native Claude model integration. This comprehensive comparison helps you choose between these industry-defining tools.
Overview
Codex CLI
Codex CLI is OpenAI's open-source coding agent that runs locally from your terminal. Built in Rust for speed and efficiency, it can read, change, and run code on your machine with a full-screen terminal UI for real-time collaboration.
Key Highlights:
- Open source (built in Rust)
- GPT-5-Codex optimized for software engineering
- Full-screen terminal UI with real-time collaboration
- Session management with local transcripts
- Cloud integration for remote tasks
- Agent Skills system with SKILL.md files
- Included with ChatGPT Plus/Pro/Business/Enterprise
Claude Code
Claude Code is Anthropic's official agentic coding tool that lives in your terminal, understands your codebase, and helps you code faster through natural language commands. It features checkpoint rollback and native Claude model integration.
Key Highlights:
- Official Anthropic product
- Claude Opus 4.5 with thinking mode by default
- Checkpoint system with instant rewind (Esc Esc)
- Native VS Code and JetBrains extensions
- Subagents for parallel development workflows
- Background tasks for long-running processes
- Claude Code on the web for GitHub-connected sessions
Terminal-Bench Performance
Both tools have been benchmarked on Terminal-Bench:
| Agent | Model | Score |
|---|---|---|
| Claude Code | Opus | 43.2% |
| Codex CLI | GPT-5 | 42.8% |
Analysis: The scores are remarkably close, with Claude Code holding a slight edge. However, third-party agents like Droid CLI have achieved higher scores with both underlying models, suggesting agent architecture can be as important as the model itself.
Technical Architecture
| Aspect | Codex CLI | Claude Code |
|---|---|---|
| Developer | OpenAI | Anthropic |
| Language | Rust | TypeScript/Node.js |
| License | Open Source | Proprietary |
| Runtime | Native binary | Node.js |
| Platform | macOS, Linux, Windows | macOS, Linux |
| Source Code | Available (GitHub) | Closed |
| Pricing | ChatGPT subscription | Claude subscription |
Analysis: Codex CLI's open-source Rust implementation offers transparency and native performance. Claude Code's Node.js architecture integrates well with the npm ecosystem but keeps implementation details private.
AI Model Support
| Feature | Codex CLI | Claude Code |
|---|---|---|
| Primary Model | GPT-5-Codex | Claude Opus 4.5 |
| Alternative Models | GPT-5 | Claude Sonnet 4 |
| Model Switching | Yes (/model) | Yes (--model flag) |
| Reasoning Levels | Adjustable | Thinking mode (default on) |
| Other Providers | No | No |
| Model Optimization | GPT-5-Codex tuned for coding | Claude-specific |
Analysis: Both tools are locked to their respective model families. Codex CLI offers GPT-5-Codex specifically optimized for agentic software engineering. Claude Code ships with Opus 4.5's thinking mode enabled by default for enhanced reasoning.
Pricing and Access
Codex CLI
| Plan | Details |
|---|---|
| ChatGPT Plus | $20/month, includes Codex |
| ChatGPT Pro | Higher limits |
| ChatGPT Business | Team features |
| ChatGPT Enterprise | Custom enterprise plans |
Claude Code
| Plan | Details |
|---|---|
| Claude Pro | $20/month, includes Claude Code |
| Claude Max | Higher limits for power users |
| API | Pay-per-token via Anthropic API |
| Enterprise | Claude for Work custom plans |
Analysis: Both tools are included with their respective $20/month consumer subscriptions, making them directly price-competitive. Enterprise options are available from both providers.
Terminal User Interface
| Feature | Codex CLI | Claude Code |
|---|---|---|
| Framework | Custom (Rust) | Ink (React for CLI) |
| UI Style | Full-screen TUI | Inline responses |
| Plan Preview | Shows plan before changes | Checkpoint-based |
| Approval Flow | Inline approve/reject | Tool approval prompts |
| Screenshots | Can receive screenshots | Can receive screenshots |
| Code Snippets | Direct paste support | Direct paste support |
Analysis: Codex CLI emphasizes a full-screen collaborative experience where you watch and approve Codex's plan in real-time. Claude Code provides checkpoint-based iteration with instant rollback capabilities.
Session and State Management
Codex CLI
Session Features:
- Local transcript storage
- Resume previous sessions with
codex resume - Maintains repository state and instructions
- Cloud task integration
# Resume a previous session
codex resume
# List previous sessions
codex sessions
Claude Code
Checkpoint System:
- Automatic checkpoints before each change
- Instant rewind with Esc Esc or /rewind
- Choose to restore code, conversation, or both
- Local session persistence with compaction
# Rewind to previous checkpoint
/rewind
# Or press Esc twice for instant rewind
Analysis: Claude Code's checkpoint system is more sophisticated for iterative development, allowing granular rollback of both code and conversation. Codex CLI focuses on session continuity with cloud integration for remote tasks.
Approval and Security Modes
Codex CLI Approval Modes
| Mode | Capabilities |
|---|---|
| Read-only | Explicit approvals for all actions |
| Auto | Full workspace access, approvals outside workspace |
| Full Access | Read anywhere, run commands with network |
Claude Code Modes
| Mode | Description |
|---|---|
| Interactive | Full tool access with approval prompts |
| Headless (-p) | Programmatic CI/CD integration |
| Agent Mode | Custom agent configurations |
| Background | Long-running non-blocking processes |
Analysis: Codex CLI's three-tier approval system provides clear security boundaries. Claude Code's approach is more flexible with custom agent configurations and background task support.
Skills and Extensions
Codex CLI Agent Skills
SKILL.md System:
- Skills defined in Markdown files
- Include scripts, resources, and assets
- Available in CLI and IDE extensions
- Captures specific capabilities
# SKILL.md example
name: database-migration
description: Handles database schema migrations
tools:
- shell
- file_write
Claude Code Custom Agents
Agent Configuration:
- Custom system prompts
- Tool restrictions per agent
- Model selection per agent
- Via --agent CLI flag
# Use custom agent
claude --agent code-reviewer -p "Review changes"
Analysis: Both support extensibility but differently. Codex CLI's SKILL.md is asset-focused, bundling instructions with resources. Claude Code's agent system focuses on configuring behavior and permissions.
Cloud and Web Integration
Codex CLI
Cloud Features:
- Interact with cloud tasks from terminal
codex cloud execfor remote task submission- Apply diffs from cloud tasks locally
- Sync between local and cloud workflows
Claude Code
Web Features:
- Claude Code on the web (GitHub-connected)
- Start sessions without terminal
- Claude in Chrome (beta) for browser control
- Session continuity between web and CLI
Analysis: Codex CLI's cloud integration focuses on compute offloading. Claude Code's web presence emphasizes accessibility with GitHub-connected sessions and browser automation.
MCP (Model Context Protocol) Support
| Feature | Codex CLI | Claude Code |
|---|---|---|
| MCP Support | Yes | Yes |
| Transport: Stdio | Yes | Yes |
| Transport: HTTP | Yes (streaming) | Yes |
| Configuration | ~/.codex/config.toml | Config files |
| Server Management | codex mcp commands | Manual |
| Run as MCP Server | Yes | Not documented |
Analysis: Both support MCP for extending functionality. Codex CLI can uniquely run as an MCP server itself, allowing other agents to consume its capabilities.
Code Review
Codex CLI
Built-in code review feature:
# Get code reviewed before commit
codex review
- Separate Codex agent reviews your code
- Pre-commit and pre-push integration
Claude Code
- Manual code review via prompts
- Custom code-reviewer agents configurable
- No dedicated built-in review command
Analysis: Codex CLI has a first-class code review feature built-in. Claude Code requires configuring custom agents or manual prompting for review workflows.
CI/CD Integration
Codex CLI
# Non-interactive execution for CI
codex exec "Fix the failing tests"
# Short form
codex e "Run linting and fix issues"
Features:
- Designed for scripted/CI runs
- Non-interactive completion
- Structured output support
Claude Code
# Headless mode for CI
claude -p "Fix the failing tests"
# With specific agent
claude --agent ci-fixer -p "Fix build errors"
Features:
- Headless mode with -p flag
- Built-in tools and system prompt
- JSON output format option
Analysis: Both support CI/CD integration with non-interactive modes. Codex CLI's exec command and Claude Code's -p flag serve similar purposes for automation pipelines.
IDE Integration
| IDE | Codex CLI | Claude Code |
|---|---|---|
| VS Code | Extension available | Native extension |
| Cursor | Via VS Code | Via VS Code |
| JetBrains | Extension available | Native extension |
| Skills/Agents | Shared with CLI | Shared with CLI |
Analysis: Both provide comprehensive IDE integration with extensions for major editors. Skills and agent configurations work across CLI and IDE in both tools.
Unique Features
Codex CLI Exclusive
- Open Source - Full source code available on GitHub
- Rust Performance - Native binary speed and efficiency
- GPT-5-Codex - Model specifically optimized for coding agents
- Cloud Tasks - Remote task execution and diff application
- Run as MCP Server - Other agents can consume Codex
- Built-in Code Review - Dedicated review command
- SKILL.md System - Asset-bundled skill definitions
- Screenshot Input - Direct screenshot analysis in composer
Claude Code Exclusive
- Checkpoint System - Instant rewind with Esc Esc
- Thinking Mode - Opus 4.5 extended reasoning by default
- Subagents - Parallel development workflows
- Background Tasks - Non-blocking long-running processes
- Claude in Chrome - Browser control (beta)
- Claude Code on Web - GitHub-connected sessions
- Analytics API - Organizational usage metrics
- Conversation Rollback - Restore both code and conversation
Use Case Recommendations
Choose Codex CLI If You:
- Prefer open-source tools you can inspect
- Are already a ChatGPT Plus/Pro subscriber
- Want GPT-5-Codex optimized for software engineering
- Need cloud task execution for heavy workloads
- Want built-in code review before commits
- Need to run the agent as an MCP server
- Prefer Rust's native performance
- Want screenshot input in your workflows
Choose Claude Code If You:
- Want checkpoint-based instant rollback
- Prefer thinking mode for complex reasoning
- Need parallel development with subagents
- Want browser automation via Claude in Chrome
- Need GitHub-connected web sessions
- Are already a Claude Pro/Max subscriber
- Need Analytics API for organizational metrics
- Want background task support
Head-to-Head Comparison
| Category | Winner | Reason |
|---|---|---|
| Open Source | Codex CLI | Full source on GitHub |
| Benchmark Score | Claude Code | 43.2% vs 42.8% (marginal) |
| Checkpoint/Rollback | Claude Code | Instant rewind with Esc Esc |
| Performance | Codex CLI | Rust native binary |
| Code Review | Codex CLI | Built-in review command |
| Cloud Integration | Codex CLI | Cloud task execution |
| Thinking/Reasoning | Claude Code | Opus 4.5 thinking mode |
| Subagents | Claude Code | Parallel workflow support |
| Web Access | Claude Code | GitHub-connected sessions |
| MCP Flexibility | Codex CLI | Can run as MCP server |
| IDE Integration | Tie | Both have native extensions |
| Price | Tie | Both $20/month consumer tier |
Migration Considerations
From Codex CLI to Claude Code
- Skills need conversion to Claude agent format
- Cloud tasks not available in Claude Code
- Note: Code review requires manual setup
- Benefit: Checkpoint system for iteration
- Benefit: Thinking mode for complex tasks
- Benefit: Subagent parallel workflows
From Claude Code to Codex CLI
- Agents need conversion to SKILL.md format
- Checkpoint system not available
- Note: Subagents not available
- Benefit: Open source transparency
- Benefit: Cloud task offloading
- Benefit: Built-in code review
Conclusion
Codex CLI and Claude Code represent the terminal coding agents from the two leading AI labs:
Codex CLI excels in transparency and extensibility. Its open-source Rust codebase, GPT-5-Codex optimization, and cloud task integration make it ideal for developers who value inspectable code, native performance, and the ability to offload heavy tasks to the cloud. The built-in code review and MCP server capabilities add unique workflow options.
Claude Code excels in iterative development and advanced reasoning. The checkpoint system with instant rollback, Opus 4.5's thinking mode, and subagent parallel workflows provide a sophisticated development experience. Features like Claude in Chrome and web-based sessions expand its utility beyond the terminal.
Both tools are priced identically at the consumer tier ($20/month), so the choice comes down to:
- Open source and cloud tasks? → Codex CLI
- Checkpoints and advanced reasoning? → Claude Code
- Already using ChatGPT? → Codex CLI
- Already using Claude? → Claude Code
Both represent excellent choices for AI-assisted terminal development, each optimized around their respective model families' strengths.
Looking for more flexibility? Discover NovaKit CLI - combining semantic code search, full LSP integration, and support for multiple AI providers in one powerful tool.