Gemini CLI vs Claude Code vs Codex

The three major CLI coding agents — Gemini CLI, Claude Code, and OpenAI Codex CLI — share the same fundamental pattern: an AI model connected to file system tools in a terminal. But each has distinct strengths that make it the right choice for different scenarios. Understanding these differences is not about picking a winner — it is about knowing which tool to reach for when.

Gemini CLI's primary advantages are its 1M token context window (vs ~200K for Claude Code and ~200K for Codex), native Google Search grounding (no other CLI agent can search the web natively), the extensions ecosystem (especially for Google Cloud), and the free tier with Google account authentication. Its open-source Apache 2.0 license means full transparency and community contribution. The tradeoff: the Gemini model's code generation quality varies by language and framework, and the extensions ecosystem is younger than Claude Code's MCP ecosystem.

FEATURE COMPARISON (as of mid-2026)

                    Gemini CLI      Claude Code     Codex CLI
Context window       1M tokens       200K tokens     200K tokens
Web search           Built-in        No              No
Free tier            Yes (Google)    No              No
Sandbox              Docker/Podman   macOS sandbox   Docker
Extensions           Gallery         MCP servers     Plugins
Open source          Apache 2.0      Source-avail    Open source
IDE integration      VS Code (GCA)   VS Code/JB      VS Code
Multimodal input     Images/PDF      Images/PDF      Limited
Project memory       GEMINI.md       CLAUDE.md       AGENTS.md
Custom commands      .toml files     Skills          Commands
Headless mode        -p flag         --print flag    -p flag