Claude Code isn't actually free - the binary installs free, but using it requires a paid Claude plan or an Anthropic API balance. cto CLI is the free-forever alternative that does what Claude Code does (terminal coding agent, MCP-native) plus runs any frontier model - Claude Opus 4.8, GPT-5.5, Gemini 3.1 Pro, GPT-5.3 Codex, and 6 more - through one config flag. Ad-supported, no credit card, no API key.
Install in 30 seconds
curl -fsSL https://cto.new/install | bash
Then run cto from any project directory. First launch opens your browser to log you in (email or GitHub); subsequent runs are silent. That's the entire onboarding.
What "free" actually means here
| Question | Answer |
|---|---|
| Credit card to start? | No |
| API key required? | No |
| Per-token charge? | No |
| Daily/weekly cap? | Yes - rolling 24-hour and 7-day windows |
| Ad-supported? | Yes - short inline ads in the CLI session |
| Premium tier exists? | Yes - raises limits, unlocks premium models + agent features |
This is not a trial. It's a permanent free tier with rolling usage windows (not a fixed-midnight reset). If you hit the cap, you wait until the rolling window slides forward, or upgrade.
Compared to other "free" CLIs:
| Path | What "free" gets you |
|---|---|
| cto CLI free | Sign in → use any model up to the rolling 24h+7d cap, no card |
| Claude Code free | The binary, then a paywall - no actual usage without paid Claude or API balance |
| Cursor CLI free | 7-day Hobby trial only |
| Aider free | The CLI; you pay providers directly per token |
| GitHub Copilot CLI free | Tight usage caps on the Copilot Free tier |
| Codex CLI free | The binary; needs a ChatGPT plan or OpenAI API key |
| Gemini CLI free | 60 req/min, 1,000 req/day with a Google account |
What you actually get
Every frontier model, no API keys
The cto.new gateway exposes every frontier model through one account. Pick whichever you want via opencode's /model slash command inside the TUI - no API keys to wire up, no provider dashboards to watch.
Models in the gateway:
- Anthropic - Claude Opus 4.8, Claude Sonnet 4.6
- OpenAI - GPT-5.5, GPT-5.3 Codex
- Google - Gemini 3.5 Flash, Gemini 3.1 Pro
- Open frontier - GLM 5.1, Grok 4.20, Kimi K2.6, MiniMax M2.7
opencode-native MCP
cto CLI uses opencode's native MCP support. Whatever MCP server you'd wire into opencode (stdio or streamable HTTP), you wire into cto CLI the same way. The MCP ecosystem has 9,400+ public servers covering Linear, Sentry, Notion, Supabase, your custom systems - all of them work.
Same opencode core
cto CLI ships as an opencode plugin + provider. opencode is the open-source TUI coding agent (Apache 2.0) that handles the agent loop, file editing, plan mode, worktrees, slash commands, hooks, skills, LSP, and native MCP - all running locally in your terminal. cto's plugin adds install/auth/upgrade and the ads layer; cto's provider is the cto.new gateway that handles LLM calls so you don't bring keys.
Quickstart: what to try first
# Drop into any project
cd your-project
cto
# Then in the TUI:
> write tests for the auth module and run them
> /model openai/gpt-5.5 # Switch model per session
> /mcp # See which MCP servers are enabled
The CLI supports piping like tail -200 app.log | cto -p "find anomalies".
When cto CLI is the right swap from Claude Code
Pick cto CLI if:
- You don't want to pay for Claude Pro or Max just to use a coding agent.
- You want to use models beyond Claude on the same CLI without a third-party-provider dance.
- You're scripting from CI and don't want to provision a paid-plan budget.
- You'd rather have a managed gateway than juggle Anthropic + OpenAI + Google API keys.
Stay on Claude Code if:
- You're committed to Anthropic and want the deepest Claude-native UX.
- You use Anthropic-managed features (Routines, Dispatch, multi-surface continuity).
- Your team is fully standardized on Anthropic billing.
You can also run both - they coexist fine.
FAQ
Is Claude Code actually free?
The Claude Code binary installs free. To use it, you need a paid Claude plan (Pro $20/mo, Max $200/mo), an Anthropic Console balance, or a third-party provider you're paying separately. There's no genuinely-free path inside Claude Code.
Is cto CLI free with no card?
Yes. Sign in with email or GitHub, use the CLI on the free tier with rolling 24h+7d usage windows. Premium tier exists (raises the windows, unlocks premium models + agent features), but you don't have to enter a card to start.
Does cto CLI work with Claude?
Yes - Claude Opus 4.8 and Sonnet 4.6 are in the gateway. Pick either via opencode's /model slash command, no API key required.
What's the rolling 24-hour and 7-day window?
The cap is measured as your usage over the trailing 24 hours and the trailing 7 days. As old usage slides out of the window, your effective remaining budget grows. There's no fixed-midnight reset.
Can I use cto CLI in CI?
Yes - cto -p "prompt" works in scripts and GitHub Actions. CI usage counts against your rolling window like any other usage. Heavy CI throughput typically wants premium.
What's the difference between cto CLI and opencode?
cto CLI ships as an opencode plugin + provider. opencode is open source (Apache 2.0) and BYOK by default - you bring API keys for whichever provider. cto's plugin layer adds install/auth/upgrade and the ads layer; cto's provider is the cto.new gateway that handles LLM calls so you don't manage keys, plus you get a free tier via ads.
Does cto CLI support MCP?
Yes - opencode-native MCP support. Configure your MCP servers (stdio or streamable HTTP) in opencode's standard MCP config and the agent picks them up. Whatever MCP server you want - Linear, Sentry, Notion, your own - works the same way it does in vanilla opencode.