For AI agents · MCP server

Give your assistant a living sky to query.

Your assistant already knows how to hold a conversation. Now it can look up. Ask about tonight's sky, someone's chart, the next eclipse — and it quietly reaches for the real numbers instead of making them up.

Add to Claude Read the Docs

things it can look up: 84 tools; things it can look up
answers from real data: No guessing; answers from real data
to connect it: One click; to connect it

Claude · connected to OpenEphemerislive

Draw my birth chart — March 21 1990, noon, London.

ephemeris_chart_wheel1.2s

Here's your chart. Sun at 0°36′ Aries — you were born within an hour of the spring equinox. Want me to look at your transits next?

Actual API output — not a mock-up

Connect it now

One connector, about thirty seconds. Signing in creates your free account — nothing to install.

Zero install

Connect Claude in ~30 seconds

A remote MCP connector — no download, no API key. OAuth handles sign-in and creates your account on first connect.

1Click "Add to Claude" above — it copies the URL and opens Claude → Settings → Connectors.
2Click "Add custom connector", then paste the URL into the URL field (Ctrl/⌘+V).
3Leave the OAuth Client ID and Secret blank and click "Add". Approve the sign-in popup — that also creates your free OpenEphemeris account.

Custom connectors require a paid Claude plan (Pro or higher). On the Claude desktop app and Claude Code, all plans work.

Using Claude Desktop, Cursor, or another client? See all setup options →

On Claude's free plan? Use the Claude Desktop config below — every plan works there.

Your birth data never trains a model — we don't sell it, share it, or feed it to anyone. Privacy policy

OpenEphemeris connected in Claude: asked for a natal chart in plain language, Claude calls the tool and a real computed chart wheel renders in the conversation

Say it plainly. It handles the rest.

You ask in your own words. Claude picks the right tool, sends the right parameters, and answers from computed data.

“What's in the sky right now?”

A live snapshot of every planet, tonight.

current_sky_snapshot

“Draw my birth chart.”

An interactive wheel you can click and explore.

explore_natal_chart

“Are we actually compatible?”

Two charts, honestly compared.

ephemeris_synastry

“Where on Earth am I luckiest?”

Your planetary lines drawn across the map.

acg_power_lines

“Any big transits hitting me this month?”

Exact dates, not vague vibes.

ephemeris_natal_transits

“What's my Human Design type?”

An interactive bodygraph — type, strategy, authority.

explore_human_design

“When is the next eclipse?”

Down to the minute, anywhere on Earth.

ephemeris_next_eclipse

“Read my Chinese four pillars.”

BaZi chart with Ten Gods and luck pillars.

chinese_bazi

Free to start. Pennies to keep going.

Every account starts with 150 free credits — about 150 natal charts, no card. Richer questions cost more credits (synastry 3, maps 10). When they run low, top up your wallet for a few dollars. No subscription, no monthly bill. Credits never expire.

150 credits

≈ 150 natal charts

$10

350 credits

≈ 350 natal charts

$20

900 credits

≈ 900 natal charts

Pay only for what you use

Start free Full pricing & plans

Not using Claude.ai?

The same 84 tools work in Claude Desktop, Claude Code, Cursor, Windsurf, ChatGPT, and any MCP-compatible client.

json

{
  "mcpServers": {
    "openephemeris": {
      "command": "npx",
      "args": ["-y", "@openephemeris/mcp-server"]
    }
  }
}

Settings → Developer → Edit Config. Paste, save, restart. No API key required — first tool call prompts you to link your account.

Self-hosted and CLI clients authenticate with an API key from your dashboard. Free Explorer tier — 150 credits to start (one-time), no card required.