Use AstroCalc in Claude and ChatGPT

What it does

Ask an AI "what's my Moon sign?" and it will often guess. A kundli needs the exact positions of the planets at your birth, and a chatbot can't work those out in its head. Our connector lets it ask AstroCalc instead.

Technically it's a remote MCP server (Model Context Protocol, the open standard assistants use to call outside tools). In practice: you ask in English, Hindi or Hinglish, the assistant calls AstroCalc, and you get

• your birth chart in plain words (kundli): your core nature, the life phase you're in right now and when it changes, your standout strengths, and which life areas look strong;
• how well two people match for marriage (kundli milan): the score out of 36 and what each part means, cancellations applied, and a Manglik check for both;
• timing and perspective: what a life phase (dasha) means, how rare a yoga really is, and answers from our Learn chapters.

Same engine as the website: Swiss Ephemeris, sidereal zodiac, Lahiri ayanamsa. Every answer ends with a short caveat and a link to the full free report on astrocalc.in (charts, Hindi version, PDF). The connector only reads and calculates; it can't change anything.

Free, and what sign-in adds

The six tools

You never call these by name. Talk about yourself, your family or someone you know, a change you're going through, career or marriage timing, or a match; the assistant picks the right tool.

Don't know your birth time? Say so. We use 12 noon: your Moon sign and nakshatra stay right, and the answer tells you the Lagna is approximate.

Claude, step by step

Works on claude.ai, the desktop app and the mobile apps, on every plan (the Free plan allows one custom connector).

1. Open Customize > Connectors and click Add custom connector (or use the "Add to Claude" button above, which fills this in).
2. Name: AstroCalc. URL: https://astrocalc.in/mcp. If asked how to sign in, pick No sign-in.
3. Click Add. In a chat, check AstroCalc is switched on under + > Connectors, then ask away.

Team or Enterprise plan? An Owner adds it once under Organization settings > Connectors > Add > Custom; everyone else then connects from Customize > Connectors.

ChatGPT, step by step

ChatGPT takes outside connectors through Developer mode, a beta setting. Whether your plan or workspace allows it is up to OpenAI and your admin.

1. On chatgpt.com, open Settings > Apps (called Connectors in older versions) > Advanced settings and turn on Developer mode.
2. Back under Apps, choose Create. Name: AstroCalc. URL: https://astrocalc.in/mcp. Authentication: None. Accept the note about custom servers.
3. In a new chat, open +, pick Developer mode and switch on AstroCalc.

ChatGPT renames its menus now and then; if a step looks different, search settings for "Developer mode".

Other apps

• Claude Code: claude mcp add --transport http astrocalc https://astrocalc.in/mcp
• Cursor, VS Code and other MCP apps: add a remote (HTTP) server. The "Cursor and others" button above copies this:

{
  "mcpServers": {
    "astrocalc": { "url": "https://astrocalc.in/mcp" }
  }
}

For testing, the MCP Inspector (npx @modelcontextprotocol/inspector) works with transport "Streamable HTTP" and the same URL. In the MCP Registry we're in.astrocalc/astrocalc.

Privacy

• The birth details your assistant sends (date, time, place) are only used to do the calculation, in memory. We don't store them, and no account is created.
• We note which tool was used, the assistant's name (for example "claude-ai") and the time, and keep daily counts per tool and assistant. Never your birth details. Like every website, our server also keeps standard access logs.
• If the same chart is asked for again, the answer may come from a short-lived memory cache (up to 24 hours).
• Your chat itself stays with your assistant's provider (Anthropic, OpenAI and so on), under their privacy policy.

The full version: Privacy Policy, "AI assistants".

Limits

• Free and read-only. It calculates and explains. It can't save charts, change anything or charge you.
• Fair use. About 60 requests a minute and 20 chart calculations an hour per connection, plus a shared hourly limit for all assistants together. If you hit one, the answer says how long to wait and links to the same thing on astrocalc.in.
• Dates from 1 January 1900 to today. Places come from our city list (Indian cities first), or give latitude and longitude.
• Not a prediction. This is traditional Vedic astrology for reflection, not medical, legal or financial advice. A guna score is one input, not a verdict on a relationship.

Support

Not showing up, a result that looks off, or a question about your data? Write to us; we reply within 24 to 48 hours.

Quick checks: the URL is exactly https://astrocalc.in/mcp, and "No sign-in" / "No authentication" is selected. Opening that URL in a browser brings you back to this page; that's expected.