Codex CLI vs Claude Code vs Gemini CLI
A practical comparison of the three major terminal-based coding agents. Which one should you use, and when?
The terminal-based coding agent space has consolidated around three major players. Here’s how they compare — and which one to pick.
Quick verdict
- Claude Code — best for deep codebase understanding and complex multi-file changes
- Codex CLI — best for sandboxed execution and autonomous task completion
- Gemini CLI — best for Google ecosystem integration and multimodal tasks
Most experienced developers will benefit from having at least two of these available.
Claude Code (Anthropic)
Strengths:
- Exceptional codebase understanding — navigates large projects naturally
- Extended thinking for complex reasoning about architecture and design
- Strong at multi-file refactoring and cross-cutting changes
- Excellent at explaining existing code
Weaknesses:
- No built-in sandboxing (runs in your environment directly)
- Can be expensive for large tasks (extended thinking uses more tokens)
- Anthropic API dependency
Best for: Complex refactoring, large codebase navigation, architectural changes, code review.
Codex CLI (OpenAI)
Strengths:
- Sandboxed execution environment — safe to let it run autonomously
- Good at breaking down tasks and executing step by step
- Network-disabled sandbox prevents unintended side effects
- Strong at test-driven development workflows
Weaknesses:
- Sandbox can be limiting for tasks that need network access or system tools
- Less nuanced codebase understanding than Claude Code
- OpenAI API dependency
Best for: Autonomous task completion, generating new code from specs, test-driven development, tasks where safety guardrails matter.
Gemini CLI (Google)
Strengths:
- Large context window for working with big files and codebases
- Multimodal — can process images, screenshots, diagrams alongside code
- Free tier available with generous limits
- Good integration with Google services
Weaknesses:
- Newer entrant, less mature than Claude Code and Codex
- Smaller ecosystem of integrations and extensions
- Can be verbose in responses
Best for: Multimodal tasks, working with visual references, Google ecosystem projects, cost-sensitive usage.
Feature comparison
| Feature | Claude Code | Codex CLI | Gemini CLI |
|---|---|---|---|
| Sandboxed execution | ✗ | ✓ | ✗ |
| Extended thinking | ✓ | ✗ | ✓ (limited) |
| Multimodal input | ✗ | ✗ | ✓ |
| Offline capable | ✗ | ✗ | ✗ |
| Open source | ✓ | ✓ | ✓ |
| Custom model support | ✗ | ✗ | ✗ |
Our recommendation
If you pick one: Claude Code. Its codebase understanding is a genuine step above, and complex refactoring is where coding agents provide the most value.
If you pick two: Add Codex CLI for tasks where you want sandboxed autonomous execution — letting the agent run without worrying about side effects.
If cost matters: Gemini CLI’s free tier makes it a good starting point, especially for lighter tasks.
The power move: Use all three through an orchestration layer like OpenClaw, which can delegate to the right coding agent based on the task.
This comparison is updated as these tools evolve. Last updated: March 2026.