Claude Code vs Codex CLI vs Antigravity CLI vs OpenCode
Four terminal agents, three of them from big labs and one genuinely independent. Licence and lock-in separate them more than editing quality does.
Updated August 28, 2026 · Independent comparison — Claude Code, Codex CLI, Antigravity CLI, OpenCode are separate products.
Claude Code
Anthropic's first-party coding agent
Claude Code is Anthropic's first-party coding agent, running as a CLI, as IDE extensions and inside claude.ai. It is proprietary — the public repository is not OSI-licensed. It runs on a Claude Pro or Max subscription or a pay-as-you-go API key, and can be pointed at third-party labs by aiming ANTHROPIC_BASE_URL at a GLM, Qwen or Kimi coding-plan key. Its constraint is that on a subscription its quota is shared with claude.ai chat, and extra terminals do not get their own bucket.
Codex CLI
OpenAI's open-source coding CLI
Codex CLI is open source, though the cloud product around it is not. It runs across CLI, IDE, web, iOS and Codex Cloud, on GPT-5.6 and GPT-5.3-Codex, driven either by a ChatGPT plan or an API key. Its distinguishing feature is that a consumer ChatGPT subscription includes background and cloud compute rather than only local runs — Codex Cloud tasks draw on the same quota rather than being a separate SKU.
Antigravity CLI
Google's agent-first CLI and IDE
Antigravity CLI is Google's agent-first command line, shipping alongside the Antigravity IDE and free in public preview. It runs the Gemini family, with limited non-Gemini models on a separate and smaller quota because of capacity. There is no bring-your-own-key path — AI Studio keys are a different product. It is the successor path to Gemini CLI, whose free Gemini Code Assist serving is reported to have ended on 2026-06-18.
OpenCode
MIT-licensed terminal-first agent
OpenCode is MIT-licensed and terminal-first, with a TUI plus extensions for VS Code, Cursor and Zed, and a headless mode for scripting. It reaches 75+ models through Models.dev, accepts GitHub Copilot and ChatGPT logins, and offers two first-party billing options that are entirely optional: Zen pay-as-you-go and the $10/month Go subscription. Nothing about it is locked — you can bring any key, and the Go key works in other agents too.
Bottom line
These four cover the terminal agent market, and licence is the cleanest way to tell them apart. Claude Code is proprietary and included with Claude Pro or Max, sharing its quota with claude.ai chat. Codex CLI is genuinely open source — the cloud product around it is not — is included with any ChatGPT plan, and uniquely brings background and cloud compute onto a consumer subscription. Antigravity CLI is a proprietary preview, free today, Gemini-only, with no BYOK path at all. OpenCode is MIT-licensed, reaches 75+ models through Models.dev, accepts Copilot and ChatGPT logins, and its two first-party billing options (Zen and the $10 Go plan) are entirely optional — the only one of the four with no lock-in of any kind.
Status & licence
| Feature | Claude Code | Codex CLI | Antigravity CLI | OpenCode |
|---|---|---|---|---|
| Status | Active | Active | Public preview | Active |
| Licence | Proprietary — the public repo is not OSI-licensed | Open source (the cloud product is proprietary) | Proprietary preview | MIT |
| Price | Included with Claude Pro ($20) or Max ($100/$200) | Included with ChatGPT Plus ($20) or Pro ($100/$200) | Free in public preview | Free; Go subscription $10/month is optional |
Where and how it runs
| Feature | Claude Code | Codex CLI | Antigravity CLI | OpenCode |
|---|---|---|---|---|
| Where it runs | CLI, IDE extensions, claude.ai | CLI, IDE, web, iOS, Codex Cloud | Antigravity CLI and IDE on Windows, macOS and Linux | TUI, VS Code, Cursor and Zed extensions, headless |
| Model support | Claude family; third-party labs via ANTHROPIC_BASE_URL | GPT-5.6 and GPT-5.3-Codex | Gemini family; limited non-Gemini on a separate quota | 75+ via Models.dev, plus Zen and Go |
| BYOK | Partial — Anthropic key, or an Anthropic-compatible coding-plan key | Yes, via the API-key path | ✗ | ✓ |
| Subscription support | Claude Pro or Max | ChatGPT Go, Plus or Pro | Free in preview; Google AI plans raise the quota | Optional — OpenCode Go at $10/month |
Capabilities
| Feature | Claude Code | Codex CLI | Antigravity CLI | OpenCode |
|---|---|---|---|---|
| Parallel sessions | Terminals share one subscription pool | Cloud tasks; the $200 tier is marketed for parallel projects | Multi-agent by design; the weekly cap is the throttle | Not published |
| MCP support | ✓ | ✓ | Not published | ✓ |
Verdict at a glance
| Feature | Claude Code | Codex CLI | Antigravity CLI | OpenCode |
|---|---|---|---|---|
| Standout feature | The strongest agentic editing quality | Cloud and background compute on a consumer subscription | Editor, terminal and browser agents together, at no cost | Fully open, with optional first-party billing and no lock-in |
The Verdict
Choose Claude Code if...
- ✓You want the strongest agentic editing quality
- ✓You want IDE extensions as well as a CLI
- ✓You want to point the agent at GLM, Qwen or Kimi coding-plan keys
- ✓You already pay for Claude Pro or Max
Choose Codex CLI if...
- ✓You want an open-source harness you can inspect and fork
- ✓You want cloud and background tasks on a consumer subscription
- ✓You want CLI, IDE, web and iOS coverage
- ✓You want a real BYOK path via an API key
Choose Antigravity CLI if...
- ✓Free matters and Gemini models do your work
- ✓You want editor, terminal and browser agents as one product
- ✓You are comfortable on a preview with an unpublished weekly quota
- ✓You are migrating off Gemini CLI
Choose OpenCode if...
- ✓You want MIT-licensed software with genuinely no lock-in
- ✓You want 75+ models and the freedom to bring any key
- ✓You want optional first-party billing you can ignore
- ✓You want a headless mode for scripting
- ✓You want extensions for VS Code, Cursor and Zed as well as a TUI
Frequently Asked Questions
What is the difference between Claude Code, Codex CLI, Antigravity CLI and OpenCode?
Claude Code is Anthropic's first-party coding agent, running as a CLI, as IDE extensions and inside claude.ai. Codex CLI is open source, though the cloud product around it is not. Antigravity CLI is Google's agent-first command line, shipping alongside the Antigravity IDE and free in public preview. OpenCode is MIT-licensed and terminal-first, with a TUI plus extensions for VS Code, Cursor and Zed, and a headless mode for scripting.
Which of Claude Code, Codex CLI, Antigravity CLI and OpenCode should I pick?
Choose Claude Code if you want the strongest agentic editing quality. Choose Codex CLI if you want an open-source harness you can inspect and fork. Choose Antigravity CLI if free matters and Gemini models do your work. Choose OpenCode if you want MIT-licensed software with genuinely no lock-in.
1DevToolRun them side by side instead of choosing
These agents are not mutually exclusive — they are processes, and most developers end up wanting two or three for different jobs. 1DevTool runs Claude Code, Codex CLI, Cline, OpenCode and Gemini CLI in persistent terminals in one window, each on its own subscription or key, plus an HTTP client, a 13-engine database client and an embedded browser. One-time $29, no subscription.