Vitamin D

Connect your AI

Your sun, available to your AI

The app ships an MCP server: connect Claude, ChatGPT or any other assistant and ask about the sun and your vitamin D in plain language.

Once connected, your assistant can run the same calculations the app uses — and, if you link your account, read your profile and history too. For example:

In assistants that support it, five of the tools do not just answer — they draw. A whole year for one place, several cities compared on one axis, today's curve with your window shaded, a form to set your profile with the minutes updating live, and your sun calendar, where a tap confirms a day.

  • “When can I make vitamin D today in Madrid?”
  • “Which months have enough sun in Berlin?”
  • “How is my sun month going?” (with an account)

The two connector URLs

Without an account

https://getvitamind.app/api/mcp/mcp

Sun and vitamin D calculations for anywhere in the world. No sign-up required.

With your account

https://getvitamind.app/api/mcp-auth/mcp

Everything above plus your profile, your cities and your history, behind a secure login (OAuth). Your AI will know your skin type without you repeating it.

How to connect it

Claude (claude.ai)

  1. 1Settings → Connectors → Add custom connector.
  2. 2Paste the connector URL; leave the advanced options empty.
  3. 3With the account URL, Claude will take you to the app's sign-in: log in and press Allow.

ChatGPT

  1. 1Settings → Security & sign-in → turn on “Developer mode” (flagged high risk: it allows adding unverified connectors).
  2. 2Settings → Apps & connectors → Create connector, and paste the URL.
  3. 3With the account URL, authorise access when prompted.
  4. 4“Apply CSP in developer mode” can stay on: our widgets declare their own CSP and make no network requests.

Other MCP clients

Any MCP client speaking streamable HTTP works: Claude Code, Cursor, VS Code… Client registration and the OAuth login are automatic; all you need is the URL.

What you'll see when connecting your account

The permission screen tells you exactly what your assistant can read or write. You can disconnect it anytime from your AI client.

What it can do

Without an account

  • Find cities and get their coordinates and timezone
  • Sunrise, sunset, golden hour and day length for any date and place
  • The vitamin D window for a specific day, with your minutes needed
  • The whole year at a glance: possible months and minutes per month
  • Several cities compared on one shared axis, 2 to 5 at a time
  • Is right now a good moment? With live UV and clouds
  • How much vitamin D you make in X minutes, and how long until sunburn
  • Your skin type, exposed skin, age and target, with the minutes updating live
  • get_sun_forecast — the next few days at a glance, with the best one picked

With your account

  • Read your saved profile (skin type, age, target, city)
  • Save your profile from the chat: skin type, exposed skin, age and target
  • Your favorite cities, ready to query
  • Your sun-day history and your streak
  • Log a sun day: “I went outside for 20 minutes today”
  • set_history_location — correct where you were over a range of days

Tools added after you connected

Clients fix the list of tools when the connector is added, and this server has no way to tell them it has changed. If your assistant lists fewer than 15 tools, remove the connector and add it again — nothing else is lost, and your account stays connected.

Privacy

The public URL uses no account and stores nothing about you. With the account URL, access uses OAuth with explicit permissions you approve; tokens expire on their own and your data is never shared with third parties.

Tip: even without an account, tell your assistant your skin type and city once — its memory does the rest.