Rayfin (Getting Started)

Rayfin is a Backend-as-a-Service: define your data model with TypeScript decorators and Rayfin provides auth, a typed data API, storage, and Fabric hosting.

This skill only handles getting started — getting you from zero into a working Rayfin project, then handing off. The moment you're in a project, the authoritative, version-locked skill at .agents/skills/rayfin/SKILL.md — alongside the package docs in node_modules and the rayfin docs CLI — owns everything else: schema, auth, storage, querying, deployment. Load it and stop using this one.

Route, don't improvise

Rayfin's specifics are version-locked per project — schema/decorator syntax, the typed data API and client queries, auth, storage, and deployment all live in the project's own skill and rayfin docs. Never answer them from memory; remembered Rayfin APIs are routinely wrong against the installed version. Get into a project, read .agents/skills/rayfin/SKILL.md, then follow it for version-matched signatures. The in-project skill file and the rayfin docs CLI are available the moment a project exists — including right after you scaffold one, in the same session. The rayfin MCP server is an optional extra that most projects do not install; if it happens to be available it is a convenience, never a prerequisite. Lean on the in-project skill file plus rayfin docs.

Being blocked does not unlock memory. Only treat yourself as blocked if you can reach none of the version-matched sources — you can't read .agents/skills/rayfin/SKILL.md and can't run rayfin docs (e.g. tool permissions denied). The rayfin MCP server not being installed or loaded is not a blocker. When genuinely blocked, say you need those sources to answer accurately and stop there — don't offer a "general approach" or example code "in the meantime"; that stopgap is exactly the fabrication this skill exists to prevent.

Already in a Rayfin project?

Check this first — before scaffolding anything, even when the user says "build" or "set up a new app". A directory is a Rayfin project if it has rayfin/rayfin.yml or a package.json depending on @microsoft/rayfin-*. Environment signals alone are enough: if the workspace context shows either — even when you can't open the files yet — treat it as an existing project and continue in place. Never stand up a nested or sibling project.

• Already in one → load .agents/skills/rayfin/SKILL.md and use rayfin docs (or the rayfin MCP, if already installed). Stop using this skill.
• Existing non-Rayfin app here → add Rayfin in place with npx rayfin init (don't scaffold a separate project), then load the in-project skill.
• Empty directory → scaffold (below), then load the in-project skill from the project root.

Scaffold a new project

npm create @microsoft/rayfin@latest is a thin wrapper around rayfin init. As an agent you run non-interactively (stdin isn't a TTY), so use the npx -y form — npm create can mishandle piped stdin and strip flags, and --project-name is required non-interactively.

# Create non-interactively. --project-name is required; the template is pinned.
npx -y @microsoft/create-rayfin@latest --project-name <app-name> --template universal-app

# Or add Rayfin into an existing/empty directory
npx rayfin init [directory]

Always scaffold universal-app. Don't browse the gallery and don't pick a domain-specific template. The Universal App is a deliberately small React + Vite base with a built-in capability router that pulls in the right Rayfin services, npm modules, and skills on demand, so the domain shape (analytics, CRUD, storage, functions) gets decided inside the project rather than at scaffold time. The project's own .agents/skills/ own that decision, and they are version-matched in a way a scaffold-time template choice is not.

Mind the project root before loading the in-project skill: create-rayfin creates a child project directory (named from --project-name, slugified), so cd into it; an in-place rayfin init scaffolds in the current directory, so you're already there. Once at the project root, load its .agents/skills/rayfin/SKILL.md and let its capability router take over.