The Story

Claude Code is arguably the best AI coding CLI in the world. But it's closed-source.

Then claude-code-best did the insane work of decompiling the entire thing — 43 tools, 100+ commands, 5000-line REPL, multi-provider API, MCP protocol, plugin system — all reverse-engineered from the compiled bundle.

We took that, and actually made it run.

It wasn't easy. The decompiled code was riddled with landmines:

• API 500 errors — The prompt-caching-scope-2026-01-05 beta header sends cache_control.scope:"global" on system prompts. The server rejects this from non-official builds. We had to disable all experimental betas.
• Empty streaming responses — Opus returns 200 headers but zero events, triggering a non-streaming fallback that sends thinking: {"type":"adaptive"} — which non-streaming doesn't support. We patched adjustParamsForNonStreaming to convert adaptive thinking to budget-based.
• USER_TYPE: undefined — A build-time constant that was never set, causing User-Agent: (undefined, cli). We inject "external" at runtime.
• Gates is not defined — A feature-flagged component referenced but never imported. Even wrapped in false ? ... : [], the assignment still evaluated and crashed.
• Version mismatch — Attribution header checked cc_version, rejecting anything that didn't match the official release.

Every one of these was a dead end until we added file-based debug logging (/tmp/rabbit-code-debug.log) to capture the exact HTTP request/response cycle — because the TUI swallows all stderr output.

The moment it finally worked, we literally said "wow".

Now you can run the full Claude Code experience — with your own API key, your own OAuth, your own branding — completely open.

Quick Start

The fastest way to use Rabbit Code CLI is via npx:

npx rabbit-code-cli
# or shorthand
npx rabbit

Global Install

You can also install it globally via npm, pnpm, or bun:

# Using npm
npm install -g rabbit-code-cli

# Using pnpm
pnpm add -g rabbit-code-cli

# Using bun
bun add -g rabbit-code-cli

Usage

Once installed, you can start the CLI using either:

rabbit
# or
rabbit-code-cli

From Source

cd rabbit-code-cli
pnpm install
pnpm run build
bun run dev

That's it. You should see the RABBIT-CODE ASCII art logo and be ready to code.

Requires Node.js >= 18 (to run) and Bun >= 1.3.11 (to build from source), and an Anthropic API key or Claude Pro subscription.

What's Different

| | Official Claude Code | Rabbit Code CLI | |---|---|---| | Source code | Closed | Open | | Branding | Anthropic | Yours (or ours) | | API compatibility | Official only | Any Anthropic-compatible endpoint | | Experimental betas | All enabled | Stable subset only | | Feature flags | Server-controlled | All false (clean, no dead code paths) | | Customization | None | Full source access — hack everything |

Key patches we made

fix: disable experimental betas (prompt-caching-scope, redact-thinking, context-management)
fix: set USER_TYPE="external" for correct User-Agent
fix: convert adaptive thinking → budget-based for non-streaming fallback
fix: remove Gates component reference crash
fix: match version for attribution header compatibility

Features

Everything from Claude Code, minus the feature-flagged internal stuff:

• Interactive REPL — Rich Ink-based terminal UI, streaming responses, vim mode
• Multi-provider — Anthropic Direct, AWS Bedrock, Google Vertex, Azure Foundry
• 43 Tools — File ops, bash, web search/fetch, glob/grep, agents, MCP, LSP
• 100+ Commands — /model, /compact, /doctor, /resume, /mcp, /plugin...
• MCP Protocol — Full client with stdio, SSE, HTTP transports
• Plugins & Skills — Extensible with custom commands and automation
• Smart Context — Auto git status, CLAUDE.md, memory files, reactive compaction
• Permissions — Granular plan/auto/manual tool permission modes
• Hooks — Pre/post tool use hooks for custom workflows
• Sessions — Resume, export, memory across conversations

Architecture

rabbit-code-cli/
├── src/
│   ├── entrypoints/cli.tsx    # Bootstrap + runtime polyfills
│   ├── screens/REPL.tsx       # 5000+ line interactive UI
│   ├── services/api/          # Multi-provider API (4 providers)
│   ├── services/mcp/          # MCP client (24 files, 12000+ lines)
│   ├── tools/                 # 43 tool implementations
│   ├── commands/              # 100+ slash commands
│   └── components/            # 146 Ink UI components
├── packages/                  # Internal workspace packages
├── build.ts                   # Code-splitting build (→ ~450 chunks)
└── rabbit-code-cli            # Launcher script

Contributing

Found a bug? Want to add a feature? PRs welcome.

This project exists because someone was crazy enough to decompile Claude Code, and we were crazy enough to debug it. If that resonates with you — star the repo, fork it, make it yours.

License

Apache-2.0