Fellow Aiden connector for AI assistants

Snap a photo of a coffee bag and let your AI assistant design a brew profile for it, push it to your Fellow Aiden, and remember how it tasted. Works with Claude, ChatGPT, Gemini and Le Chat.

• Photo → profile. Your assistant reads the roaster, origin, process and roast level off the bag, picks starting settings, and loads the profile onto your Aiden.
• A library that remembers. Every profile, version, tasting note and 1–5 rating is kept. Say "the Guji was a bit sour" and it reads the history and proposes the next version.
• A short brewer menu. Only what you're brewing now lives on the Aiden. Finished coffees come off the brewer but stay in the library, ready to reload when you buy that bag again.
• Your gear counts. Record your grinder, filters and water. Profiles carry a grind setting for your grinder, and each tasting notes what gear you used.
• Shared profiles. Preview and import brew.link profiles, share your own, and have your assistant search the web for profiles other people have shared.
• Schedules. Set up and toggle the Aiden's scheduled brews.

It runs free on Cloudflare Workers, on your own account. Nothing runs on your home network.

Unofficial and not affiliated with Fellow. It uses the same undocumented cloud API as the Fellow app, which could change without notice.

1. Deploy it (about 5 minutes)

You need a free Cloudflare account (no card) and a free GitHub account.

On the setup screen:

1. Git account: pick your GitHub account. Cloudflare copies this project into a new repo there and deploys from it.

2. Project name: anything, e.g. aiden-connector. It becomes part of your URL. It must not match a repo name you already have.

3. Storage and database: leave as Create new.

4. Secrets:

   Secret	What to enter
   FELLOW_EMAIL	The email you sign in to the Fellow app with
   FELLOW_PASSWORD	Your Fellow app password
   ACCESS_PASSWORD	A new password you make up, 12+ characters. You'll type it once when connecting your AI app.

5. Click Deploy and wait a minute or two.

Check it. Open your Worker's address, like https://aiden-connector.<you>.workers.dev. You should see three green checks and your connector URL, which ends in /mcp. Copy it for the next step.

Fix a secret later: Cloudflare dashboard → ☰ → Workers & Pages → your Worker → Settings → Variables and Secrets. Edit and save; it takes effect immediately. (The account-wide "Secrets Store" is a different feature — you don't need it.)

2. Connect your AI app

Every app uses the same connector URL. When a sign-in page appears, enter your ACCESS_PASSWORD and tap Allow.

Claude

Works on every plan, including Free (Free allows one custom connector).

1. Customize → Connectors, then + Add → Add custom connector. On Team or Enterprise, an owner adds it under Organization settings → Connectors first.
2. Name it Fellow Aiden, paste the connector URL, and click Continue.
3. Keep the detected sign-in settings and click Add, then sign in.
4. In a chat, use + → Connectors to make sure it's turned on.

The brewing guide (how to design and adjust profiles) reaches Claude automatically when it connects.

ChatGPT

Custom connectors need Developer mode. Which plans get it, and whether write actions (saving and loading profiles) are allowed, varies by plan; Business, Enterprise and Edu have full support.

1. On chatgpt.com (web): Settings → Apps & Connectors → Advanced settings, turn on Developer mode. Workspace admins may need to allow it first.
2. Back in Apps & Connectors, click Create. Name it Fellow Aiden, paste the connector URL, set Authentication to OAuth, and create it. Sign in when asked.
3. In a chat, use + → More and pick the connector.

ChatGPT may not follow the brewing guide the server sends. For best results, create a Project and paste the contents of skills/aiden-brewing/SKILL.md into its instructions.

Gemini

Custom apps currently need a personal Google account, age 18+, in the US, with Keep Activity on, and are added on the web only (they then work in the mobile app too).

1. At gemini.google.com: Settings → Connected Apps (or Personal Intelligence → Connected Apps).
2. Under Custom apps, click Add a custom app, paste the connector URL, click Next, and sign in.
3. In a chat, type @ and pick the app.

If Gemini doesn't follow the brewing guide, paste SKILL.md into a Gem's instructions.

Le Chat (Mistral)

Account owners on Free, Pro and Student plans can add connectors.

1. Intelligence → Connectors → + Add Connector, then the Custom MCP Connector tab.
2. Name it FellowAiden (no spaces or special characters), paste the connector URL, and click Connect. Sign in when asked.

Perplexity, Copilot and others

• Perplexity (Pro / Enterprise) has custom remote connectors under Settings → + Custom connector → Remote, but a known Perplexity bug can break sign-in with servers like this one. It may or may not work for you.
• Microsoft Copilot supports custom MCP servers only for organizations (Microsoft 365 / Copilot Studio), set up by an admin.
• Any other MCP client that supports remote servers with OAuth 2.1 should work: the server supports PKCE (S256), dynamic client registration, client ID metadata documents, and RFC 9207 issuer identification.

3. First steps

1. "What's on my Aiden? Save it all to my library." Copies your existing profiles into the library.
2. Tell it your gear: "I use a Baratza Encore, Hario V60 #02 filters for single cups, the Aiden's stock filter for the carafe, and RO water."
3. Send a photo of a bag: "Make me a profile for this."
4. After brewing: "The Mast was a bit sour, 3 out of 5." It proposes the next version.
5. Trim the menu: "Take everything off the brewer except my two current coffees."

More things to ask:

• "What did I like best from Ethiopia?"
• "That bag's done. Take its profile off the brewer."
• "Find a shared brew.link profile for Onyx Monarch and compare it to mine."
• "Brew the Kenya at 6:30 on weekdays, 600 ml."

Troubleshooting

Keeping your copy up to date

The Deploy button made a copy of this project in your GitHub, and your Worker redeploys whenever that copy changes. Fixes made here don't flow to your copy automatically. To update: replace your copy's src/ and skills/ folders with the latest ones from this repo, but keep your own wrangler.jsonc. It holds the IDs of your database and storage. Commit, and Cloudflare redeploys.

How it works

AI app ──OAuth──▶ Cloudflare Worker ──HTTPS──▶ Fellow cloud API ──Wi-Fi──▶ Aiden
                       │
                       └── D1 library: coffees · profile versions · tastings · equipment

• Sign-in. The Worker is its own OAuth 2.1 server (Cloudflare's workers-oauth-provider). Your AI app registers, you approve once with ACCESS_PASSWORD, and it gets a 1-hour token that it refreshes (refresh tokens last 30 days). The sign-in form carries the request HMAC-signed with a 15-minute expiry, so it works in in-app sign-in windows that drop cookies. Wrong passwords are throttled per network, and the page can't be framed.
• Fellow credentials are stored as encrypted Worker secrets and sent only to Fellow. Fellow has no scoped API keys, so this is your full account password; treat the Worker accordingly.
• Guardrails. Profiles are checked against the Aiden's limits before anything is sent. Revising, unloading and deleting need explicit confirmation. Built-in Fellow profiles can't be changed, and profiles used by a schedule can't be unloaded. Links between the library and the brewer are re-checked before every change, because brewer IDs get reused after deletions.
• The library database creates its own tables on first use, so there are no migrations to run.
• The brewing guide lives in skills/aiden-brewing/SKILL.md. It's bundled into the Worker and sent as the server's instructions. To change how profiles are designed and adjusted, edit that file and redeploy. For apps that ignore server instructions, paste it into a project, Gem or custom instructions. In Claude it can also be uploaded as a skill, but that isn't needed.
• Multiple brewers: if your Fellow account has more than one device, the one holding profiles is used.

Tools

Develop

npm install
cp .dev.vars.example .dev.vars   # fill in
npm run dev                      # http://localhost:8787
npm test && npm run typecheck
npm run deploy

Credits and license

Fellow API endpoints come from fellow-aiden by Brandon Dixon (GPL-3.0). This project is a TypeScript reimplementation and is also licensed under GPL-3.0.