---
title: "How Fabricator works"
description: "How Fabricator connects the GitHub Copilot agent, the Rayfin CLI, git and Microsoft Fabric into a single build, preview and ship loop."
url: https://spatney.github.io/rayfin-fabricator/docs/reference/how-it-works
markdown_url: https://spatney.github.io/rayfin-fabricator/docs/reference/how-it-works.md
app_version: "1.20.1"
section: reference
product: Fabricator
last_updated: 2026-10-09T19:32:57-07:00
source: reference/how-it-works.mdx
---

# How Fabricator works

> How Fabricator connects the GitHub Copilot agent, the Rayfin CLI, git and Microsoft Fabric into a single build, preview and ship loop.

Fabricator wraps the tools you would otherwise run by hand. You describe the app, the built-in GitHub Copilot agent edits a local Rayfin project, Fabricator previews the result, and Rayfin deploys it to Microsoft Fabric.

## The loop

1. You create, open, or clone a Rayfin project.
2. You type a request in chat.
3. The bundled Copilot engine reads and edits files in the project folder.
4. Fabricator records changes with git so you can inspect diffs and history.
5. Fabricator starts the project's local Vite frontend during chat turns when the project has Vite installed.
6. Fabricator runs the project-pinned Rayfin CLI for deploys.
7. The preview shows the deployed app, the Fabric portal shell, or the local frontend while Copilot is working.
8. The Advisor runs quick checks locally and can start a read-only Copilot review.

## Main pieces

| Piece | Where it runs | What it does |
| --- | --- | --- |
| Desktop UI | Your computer | The React workbench, chat, editor, preview, settings, history, skills, deployments, and Advisor views. |
| Tauri core | Your computer | The Rust layer that runs commands, stores app state, manages paths, handles diagnostics, hosts previews, and talks to native plugins. |
| GitHub Copilot engine | Bundled with Fabricator, connected to GitHub Copilot | The agent that reads and edits your app when you chat. |
| Project Rayfin CLI | Your project, through `npx rayfin` | Deploys the app and manages Fabric sign-in through the project's pinned Rayfin version. |
| git | Your project folder | Tracks local history, diffs, restores, and team workspace branches. |
| GitHub CLI | Your computer, through `gh` | Team workspace repositories, pull requests and pipeline runs. Each team workspace's `gh` calls and git pushes and fetches use the stored token of the workspace's own GitHub account (`gh auth token --user`), so the CLI's active account doesn't matter. |
| Local Vite preview | Your computer | Shows frontend edits during chat turns when the project has Vite installed. It uses the existing Fabric backend configuration. |
| Microsoft Fabric | Your tenant | Hosts deployed app runtimes, data, Fabric workspaces, capacities, and Fabric app items. |

## Architecture diagram

```mermaid
flowchart TD
  User["You"]

  subgraph Desktop["Fabricator desktop app"]
    UI["React workbench"]
    Core["Tauri Rust core"]
    Preview["Embedded preview"]
    Advisor["Advisor"]
  end

  subgraph Local["Local workspace"]
    Files["Project files"]
    Git["git history"]
    Vite["Local Vite frontend"]
    RayfinCli["Project Rayfin CLI"]
  end

  Copilot["GitHub Copilot service"]
  Npm["npm registry"]
  GitHub["GitHub"]

  subgraph Fabric["Microsoft Fabric"]
    Runtime["Deployed app runtime"]
    Data["Fabric data and platform services"]
    Portal["Fabric portal shell"]
  end

  User --> UI
  UI <--> Core
  UI --> Preview
  UI --> Advisor
  Core <--> Files
  Core --> Git
  Core --> Vite
  Core --> RayfinCli
  Core <--> Copilot
  Core <--> GitHub
  Core <--> Npm
  RayfinCli --> Runtime
  Runtime <--> Data
  Preview --> Vite
  Preview --> Runtime
  Preview --> Portal
  Advisor --> Files
  Advisor -. "read-only deep review" .-> Copilot

  class User actor
  class UI,Core,Preview,Advisor service
  class Files,Git,Vite,RayfinCli store
  class Copilot,Npm,GitHub external
  class Runtime,Data,Portal external
```

## What runs on your computer

Fabricator stores settings, project lists, chat history, Advisor state, logs, and diagnostics exports under the app data folder. Your Rayfin apps live in the workspace folder, which defaults to `RayfinProjects` in your home directory. See [Files and folders](https://spatney.github.io/rayfin-fabricator/docs/reference/files).

The desktop app uses Tauri v2: a Rust core with a React renderer. On Windows, the embedded preview uses WebView2. On macOS, it uses the system web view.

## Accounts

Fabricator doesn't keep credentials itself; each tool keeps its own.

- **GitHub Copilot**: the bundled Copilot engine stores the sign-in.
- **Microsoft Fabric**: the Rayfin CLI keeps one signed-in account per config folder, `~/.rayfin` by default. Fabricator gives each Fabric account added after the first its own folder under the app data folder, and points every Rayfin CLI and helper process it starts at the account in use with `RAYFIN_CONFIG_DIR`. Sign-in, sign-out and sign-in checks run the project's pinned Rayfin CLI outside the project folder, because the CLI reads the project's `rayfin.yml` at startup. The project's Fabric environment overrides in `rayfin/.env` still apply.
- **Azure CLI**: the Azure CLI keeps every account you sign in to. Fabricator lists them with `az account list`, switches with `az account set`, signs one out with `az logout --username`, and signs in with `az login --allow-no-subscriptions`, so accounts without an Azure subscription work.
- **GitHub**: the GitHub CLI keeps every account you sign in to. **Add account** runs `gh auth login` in a terminal and then switches back to your default account.

When you open Fabricator after setup has passed, it shows your work at once and checks tools and accounts in the background. Each check runs separately, so a slow one, such as Fabric's, doesn't delay the others.

## What goes over the network

Fabricator and the tools it runs can contact these services:

- GitHub Copilot for chat, model access, design options, deep Advisor reviews, and team workspace diagnoses.
- Microsoft Fabric and Rayfin services when you sign in, deploy, preview deployed apps, share apps, or inspect Fabric items.
- GitHub for update checks, release downloads, cloning repositories, issue reporting, and team workspace repositories.
- The npm registry when creating a project from the Rayfin CLI's template or installing project dependencies.
- Azure and GitHub APIs for team workspace setup and **Diagnose with Copilot** when the **Team workspaces** experiment is enabled.

## What the Advisor can read

Quick checks run locally against the project snapshot. **Run deep review** starts a read-only Copilot review. That review can read your project and rayfin.ai documentation, but it is not allowed to edit files, run commands, or open `.env` files.