C2

The document-first coding agent.
Compose structured prompts, weave in reusable skills, and run your coding CLIs through one local interface.

Website · Get started · Documentation · Architecture · Plugin standard · Plugin protocol

Important

C2 is pre-release software. Expect APIs, storage, and packaging details to change before 1.0. See the release Skill for package channels and signing limitations.

Why C2

Most coding-agent clients begin with a chat box. C2 begins with a document. You can shape a long brief with headings and lists, insert skills and files exactly where they belong, inspect the whole turn, and only then send it to the agent you choose.

• Document-first prompts. Compose in a BlockNote editor instead of squeezing a specification into a single-line input.
• Eleven coding CLIs, one protocol. Drive Claude Code, Codex, Grok, Cursor, OpenCode 1 or 2, Pi, Kimi, ZCode/GLM, Amp, and Droid through the Agent Client Protocol.
• Skills and complete plugins. Insert reusable skills inline, or install GitHub packages that can include skills, subagents, MCP servers, and project scaffolds.
• Local, inspectable continuity. Sessions and project memory live in the shared Rust core; derived memories retain their sources and can be pinned or forgotten.
• Git-aware execution. Use per-session worktrees, automatic checkpoints, diffs, revert, and explicit commit/push flows.
• Three surfaces. C2 ships an Electrobun desktop app, a ratatui TUI, and a paired remote web client. All three compose the same Rust Core through the same plugin runtime; Electrobun is the desktop shell and relays one command/event protocol to its bundled Rust host.

How it fits together

Claude Code · Codex · Grok · Cursor · OpenCode 1 · OpenCode 2 · Pi · Kimi · GLM · Amp · Droid
                              │
                         ACP over stdio
                              │
                 Rust product core
                         │
               Plugin composition layer
                    ┌─────────┼─────────┐
                    │         │         │
                Desktop      TUI      Remote
          Electrobun + React  ratatui  Axum + WebSocket

C2's internals form a runtime-module graph inspired by cordis: storage, agent execution, git, memory, scenes, and other subsystems declare what they require and provide. Separately installed extensions use the small JSON-RPC plugin protocol and only the explicitly exported Extension API; the internal Rust trait and Core commands are not the public plugin contract. Package, lifecycle, scope, security, and host behavior follow the C2 Plugin Standard.

Build from source

Start with source setup and local development. It covers the pinned Zig toolchain, desktop launch, TUI/server builds, and relevant checks. Provider setup is in the user guide.

For package channels, signing limitations, and authorized publication, use the release Skill. To operate a programming node, use the operations Skill.

Repository map

Path	Purpose
crates/kernel	Reactive plugin runtime and command registry
crates/core	Plugin-independent product domain: ACP, sessions, providers, policy, and persistence
crates/plugins	Core adapters, built-in runtime graph, extension bundles, protocol, and marketplace
crates/tui	ratatui frontend
crates/server	Headless server, pairing, WebSocket protocol, and remote client
apps/desktop	Electrobun + React + BlockNote desktop app
packages/tool-broker	Provider-neutral special-tool catalog and immutable routing plans
website	VitePress documentation and GitHub Pages site
docs	Documentation map, current contracts, designs, research, and SDLC records
script	Development, build, and repository-verification entry points

Contributing

Focused fixes, documentation improvements, and bug reports are welcome. Follow the development Skill, design system, and development lifecycle. Keep one change record with observable acceptance and actual evidence; scope and risk determine the required checks and human decisions.

Security and privacy

C2 runs provider CLIs as local child processes and communicates with them over stdio. C2 does not change the provider's own network, authentication, data-retention, or tool policies; review those separately before giving a provider access to sensitive code.

Remote access is bearer-token based and intended for a trusted LAN or Tailscale network. Do not expose codetwo-server directly to the public internet. Please report a suspected vulnerability privately to the repository owner rather than opening a public exploit report.

License

Licensed under the Apache License 2.0.