Astrology MCP server for ChatGPT, Claude and other AI assistants
AI assistants talk about astrology well but cannot calculate it. AstroProcessor's MCP server gives them your natal chart and its forecast, computed exactly, so their answers rest on real planet positions.
- Claude
- ChatGPT
- Gemini CLI
Add AstroProcessor to your AI
Connect AstroProcessor using https://mcp.astroprocessor.app/mcp and read the setup guide at https://astroprocessor.app/ai-connector
Then paste it into a chat with your AI.
Setup guideWhat an astrology MCP server is
MCP, the Model Context Protocol, is an open standard that lets an AI assistant call outside tools while it answers. An astrology MCP server is such a tool for the sky: the assistant asks it for a calculation and gets back numbers it can rely on.
AstroProcessor's server works over Streamable HTTP, and you sign in with your AstroProcessor account in your browser. There is no API key to copy. Its address and the steps for each app are on the AI connector page. It is also listed in the official MCP Registry, as app.astroprocessor/astroprocessor.
Why an AI assistant needs an ephemeris
A language model does not calculate planetary positions. Asked where Mars was on a given day, it estimates from what it has read, and the degree, the sign, a retrograde or a house cusp can be wrong with nothing in the answer to show it.
With the connector, the assistant reads your chart from AstroProcessor instead of estimating it. The positions come from NASA/JPL-grade ephemeris data, computed by the same engine the AstroProcessor app uses for its charts.
What your AI can read
The tools cover your natal chart, its forecast, the techniques read against it and the sky. The forecast is four tools, one technique each. For a question about what is coming, the AI reads your directions and transits, and adds your solar return or progressions when the question needs them.
| Tool | What it answers |
|---|---|
| get_chart_data | Your own natal chart, from the birth data in your profile, as the in-app chat reads it: every planet with its sign, degree, house and dignity, the angles and the aspects. If your profile has no birth data, it saves the date, time and place you give it, once. |
| get_directions | Your symbolic directions for any date, or for now: the directed chart against your natal chart, with the dates its exact contacts fall on. They show what your life permits. |
| get_transits | Your transits for any date, or for now: the sky against your natal chart, with the dates of its exact passes, and the sky of the coming week. |
| get_solar_return | Your solar return for the year in force on any date: its exact start and end, its houses and its contacts to your natal chart. |
| get_progressions | Your secondary progressions for any date, or for now: the progressed chart against your natal chart, with the dates its exact contacts fall on. |
| get_relocation_place | Your natal chart recast for another city: the houses and angles there, the planets that change house, and your AstroMap lines near that city. |
| get_synastry | A synastry between you and another person, from the birth date, time and city you give: their chart, their planets in your houses and the contacts between the two charts. |
| get_lunar_return | Your lunar return for the current or the next lunar month: its exact start and end, its houses and its contacts to your natal chart. |
| search_astromap_cities | The cities near a few of your AstroMap lines, in the countries you choose, with the distance to each line. |
| get_moon_data | The Moon at any moment: its sign, phase, illumination and lunar day, or the exact time of the next new moon, quarter or full moon. |
| find_eclipse | The next or previous solar and lunar eclipses: their exact time and the sign they fall in. |
| get_sunrise_sunset | Sunrise and sunset on any day, where you are or in any city you name. |
| find_city | The cities a name matches, with their time zones, so the AI can tell two cities with the same name apart. |
| get_balance | Your AstroProcessor plan and balance. |
Which AI apps can use it
- ChatGPT, as a custom MCP server in Plugins. Availability depends on your ChatGPT plan.
- Claude in the browser, on desktop and on mobile, as a custom connector.
- Claude Code and Gemini CLI, with one command each.
- Any other MCP client that speaks Streamable HTTP and signs in with OAuth.
Questions to ask once it is connected
- Which house is my Moon in, and what does that say about me? With chart access, it answers from the birth data in your profile.
- What are the strongest aspects in my natal chart?
- Which planets are strong in my chart by dignity, and which are weak?
- What does my chart say about my career?
- What does the coming year hold for me? It reads your directions and transits for the date you name, or for now, and your solar return for the year.
- What would my chart look like in Lisbon? It recasts your chart for the city you name.
- How do my chart and the chart of someone born on 3 April 1991 at 14:30 in Madrid fit together? It needs the other person's birth date, time and city.
- When is the next full moon, and in which sign? And when is the next eclipse?
What it can and cannot see
The connector reads your plan and, if you allow it when you connect, your birth data, your natal chart and what is computed from it. It writes one thing: your birth data and your natal chart, once, when your profile has none. It never changes or deletes your charts, it never reads your other charts, your chat threads or your notes, and you sign in only on astroprocessor.app.
Frequently asked questions
What is MCP in astrology?
MCP is the Model Context Protocol, the standard AI assistants use to call tools. In astrology it lets ChatGPT or Claude read an exactly computed chart instead of estimating planet positions and houses.
Can ChatGPT calculate a birth chart accurately?
Not on its own: it estimates positions from what it has read. Connected to AstroProcessor's MCP server, it reads them from NASA/JPL-grade ephemeris data.
Do I need to be a developer to use it?
No. You copy one message into your AI, or follow the steps for your app on the AI connector page, then sign in with your AstroProcessor account.
Can the AI see my saved charts?
Not your saved charts. If you allow it when you connect, it reads your own natal chart, from the birth data in your profile, and computes from it: its directions, transits, solar return and progressions for any date, a relocation to another city, a synastry with a person whose birth data you give, your lunar return and the cities on your AstroMap lines. It uses them to answer questions about you. It never changes or deletes your charts, and it never reads your other charts, your chat threads or your notes. If your profile has no birth data, it can save the date, time and place you give it, once.
Is AstroProcessor's MCP server in the official MCP Registry?
Yes. It is listed in the official MCP Registry, the Model Context Protocol's public list of servers, as app.astroprocessor/astroprocessor. MCP apps and directories that read the registry find it there.