# Chopin Chopin is a GitHub Next research prototype exploring how people and repository-grounded agents can author durable documents together. A document might be an implementation plan, technical specification, RFC, proposal, or decision record. People shape the document and own its decisions; the hosted agent, currently named **Planner**, reads the selected repository, proposes changes, and asks the team when the code cannot settle a choice. > [!IMPORTANT] > Chopin is experimental research software, not a supported GitHub product or a > production-ready service. Expect incomplete workflows, operational limits, > and breaking changes. ## What Chopin explores A channel combines one repository-connected document with its collaboration context: - **Conversation** is shared by the team and the hosted agent. Ordinary messages do not start an agent turn, although they can enter its bounded context; `@chopin` asks Chopin to act. - **Document** is a multiplayer rich-text artifact backed by readable, restricted MDX. The current interface labels this view **Plan**. People and the agent edit the same document, with presence, cursors, and transient markers for recent agent changes. - **Decisions** retain attributed questionnaire answers and accepted comments separately from the prose they produced, so a later rewrite cannot silently change what the team decided. The Planner can inspect the selected GitHub repository and its pull requests through bounded, read-only tools, then co-author the document. It cannot write to GitHub, edit a checkout, or implement code. A separate coding agent can connect to Chopin through MCP to create documents or consume an approved implementation graph. The document model supports broader artifacts, while the current Planner prompt and tool vocabulary remain optimized for planning. ## Current boundaries - Chopin supports GitHub.com. GitHub Enterprise Server endpoints are not configurable. - The Planner's file, tree, and history tools read the default branch captured when its session starts; code search is repository-scoped. It never reads a local checkout or uncommitted changes. - Every browser participant signs in, passes the instance admission policy, and needs repository access through the GitHub App installation. MCP callers also pass instance admission, but use their own bearer token for repository authorization instead of the App installation. A public repository does not make its Chopin channels public. - Pull access can view channels. Push or administration access is required to create or change them and to invoke the Planner. - The first person to invoke the Planner supplies the GitHub App user token and Copilot entitlement used for that channel. A server restart signs everyone out and releases that ownership. - Document and conversation context, along with repository material selected by the Planner, is sent to GitHub Copilot during a turn. GitHub credentials remain process-local; documents, transcripts, decisions, and token-free session records are stored in PostgreSQL. - One Chopin process may write to a database at a time. Horizontal application scaling and zero-downtime rolling deployment are not supported. ## Run locally The development path requires: - Bun 1.3.2; - Docker Engine with Docker Compose, used for PostgreSQL; - a GitHub App owned by the deployment; and - a GitHub account with push or administration access to a test repository and, to use the Planner, an active Copilot entitlement. Register these local URLs on the GitHub App: ```text Homepage: http://127.0.0.1:8787 Callback: http://127.0.0.1:8787/auth/github/callback Setup URL: http://127.0.0.1:8787/auth/github/setup ``` Enable expiring user authorization tokens, disable OAuth during installation, disable webhooks, and grant read access to Contents, Pull requests, Checks, and Commit statuses. See [Authentication](docs/authentication.md) for the exact App settings and the additional permission needed for organization admission. Install, configure, and start Chopin: ```bash bun install cp .env.example .env openssl rand -hex 32 # Fill in the GitHub App values and generated session key in .env. bun run db:up bun run migrate bun run dev ``` The committed local Compose override publishes PostgreSQL on host port 5432 and is intended only for a trusted development machine. Do not use it on an exposed host. See [Self-hosting](docs/self-hosting.md) for an internet-facing deployment. Open [http://127.0.0.1:8787](http://127.0.0.1:8787), sign in, and install or update the GitHub App when the repository picker asks. Select a repository and create a channel, then start writing. The current interface calls these planning channels. Opening the channel in a second browser profile shows the multiplayer path. Ctrl-C stops the development supervisor. `bun run db:down` tears down the local Compose project. Set `AGENT=off` to prevent Planner turns; this does not disable the `/mcp` endpoint used by external coding agents. ## Collaborate with the Planner The web composer treats `@chopin` as an instruction for the Planner: ```text should we cover the export format? -> channel conversation yes, Markdown for now -> channel conversation @chopin -> act on the recent conversation @chopin draft the export section -> act on that request ``` Recent channel conversation is supplied as bounded context for the next turn, even when those messages did not address the Planner. The first eligible editor to invoke it owns the channel's Copilot usage until their session ends or the server restarts. The current web interface has no control for transferring that ownership manually. ## Connect a coding agent Chopin exposes a bearer-authenticated Streamable HTTP MCP endpoint. See [Connect a local coding agent](docs/local-agent-mcp.md) for Claude Code, Codex CLI, and GitHub Copilot CLI configuration. Planning is one way to use a Chopin document today. The optional [creating-chopin-plans skill](skills/creating-chopin-plans/SKILL.md) turns a settled coding-agent conversation into an initial plan document. [Implementation handoff](docs/implementation-lifecycle.md) and the [implementing-chopin-plans skill](skills/implementing-chopin-plans/SKILL.md) are experimental. The supported read-before-claim flow works only for documents created through MCP, and Chopin does not yet provide a user-facing way to approve a draft graph. ## Documentation | Topic | Document | | ------------------------------------------ | ------------------------------------------------------------ | | Deploy and operate an instance | [Self-hosting](docs/self-hosting.md) | | Configure identity and access | [Authentication](docs/authentication.md) | | Connect an external coding agent | [Local agent MCP](docs/local-agent-mcp.md) | | Understand the system | [Architecture](docs/architecture.md) | | Understand channel identity and access | [Repository channels](docs/channels.md) | | Understand persistence | [Storage](docs/storage.md) | | Review the hosted agent boundary | [Hosted agent](docs/hosted-agent.md) | | Review experimental implementation handoff | [Implementation lifecycle](docs/implementation-lifecycle.md) | | Develop on exe.dev | [exe.dev development](docs/exe-dev.md) | | Test an authenticated PR preview | [PR preview testing](docs/preview-testing.md) | | Work on the repository | [Maintainer guide](AGENTS.md) | ## Development ```bash bun test # unit and in-memory adapter tests bun run test:postgres # PostgreSQL storage contract and lifecycle tests bun run e2e # browser and system integration suite bun run types # TypeScript checks across the workspace bun run ci # formatting, lint, and token checks ``` Run `bun run e2e:browsers` once to install Chromium. The browser suite builds the client and starts disposable PostgreSQL services and application servers. See [AGENTS.md](AGENTS.md) for repository structure, test selection, and current engineering invariants. Security reports should follow [SECURITY.md](SECURITY.md). Participation is covered by the [Code of Conduct](CODE_OF_CONDUCT.md), and the source is available under the [MIT License](LICENSE.md).