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Vedic astrology API · ChatGPT Action · MCP for Claude & Cursor

Put a real Vedic astrology engine inside your AI

Eternal Evals is a computation-first Jyotish engine on the Swiss Ephemeris. Most astrology sites publish articles about charts. We let your AI compute one — deterministically, for any exact birth — then read it section by section. Connect it three ways.

1 · ChatGPT

A ready-made Custom GPT that calls the engine through a GPT Action. Zero setup — just chat.

Open the GPT →

2 · Claude & Cursor (MCP)

An MCP server exposing compute_chart, read_section and list_sections as native tools.

Set up MCP →

3 · REST API

A plain JSON API. Compute a chart, then read any of ~70 sections on demand.

Read the API →

What the engine computes

Every result is a real, deterministic computation — not content keyed to a Sun sign. From an exact birth date, time and place, the engine (Swiss Ephemeris DE441, Lahiri ayanamsa, whole-sign houses by default) computes the sidereal chart and its full classical stack: planets, houses and lagna; 16 divisional (varga) charts; Vimshottari plus 21 conditional dasha systems; shadbala strength in rupas; ashtakavarga bindus; 100+ yogas; nakshatra structure; and live transits. Identical input yields byte-identical output, and every number is auditable. The engine only computes — your model does the interpretation.

The REST API

Two steps: compute a chart to get a chart_id and the list of section names, then read the sections you need (the full chart is large, so you fetch sections on demand).

# 1. Compute a chart
curl -s -X POST https://eternalevals.com/api/v1/chart \
  -H "Content-Type: application/json" \
  -d '{"date":"1990-07-07","time":"05:00","place":"Panipat, India"}'
# -> { "chart_id": "chart-abc123", "section_count": 71, "sections": [ ... ] }

# 2. Read a section (dot-paths work too: houses.10, planets.Saturn)
curl -s https://eternalevals.com/api/v1/chart/chart-abc123/section/vimshottari_dasha

Free with a per-IP rate limit. Add -H "Authorization: Bearer <key>" for a higher limit. The full machine-readable contract is at /openapi.json; a map of the whole site for AI crawlers is at /llms.txt.

MCP server for Claude & Cursor

The Model Context Protocol (MCP) lets assistants like Claude Desktop, Cursor and Cline call external tools. Our MCP server wraps the API as three tools — compute_chart, read_section, list_sections — so the assistant computes and reads a real Vedic chart natively, no copy-paste.

# Get the server + its dependencies
curl -O https://eternalevals.com/mcp/eternalevals_mcp.py
pip install mcp httpx

Then point your client at it. For Claude Desktop, add this to claude_desktop_config.json (Settings → Developer → Edit Config):

{
  "mcpServers": {
    "eternal-evals": {
      "command": "python",
      "args": ["/absolute/path/to/eternalevals_mcp.py"],
      "env": { "ETERNALEVALS_API_KEY": "" }
    }
  }
}

Cursor and Cline use the same command and env in their MCP settings. The API key is optional — leave it blank to use the free anonymous limit, or set a bearer key for a higher one. Restart the client and you'll see the three tools appear.

Why compute, not content

Ask a generic astrology chatbot about your Saturn and it may invent a placement that was never calculated — confident prose over unstable facts. Eternal Evals separates the two jobs: a deterministic engine computes the chart first, and the AI reads what the engine produced. That is the difference between a tool that talks about astrology and one that answers about your chart — and it is why an AI grounded in this engine can show the exact placement, strength or period behind any claim.

Frequently asked

Is there a Vedic astrology API?

Yes — a free JSON REST API at /api/v1. POST birth details to /api/v1/chart for a chart_id and the list of ~70 sections, then GET the sections you need.

How do I use the engine in ChatGPT?

Open the Eternal Evals Custom GPT, or build your own GPT by importing https://eternalevals.com/openapi.json as an Action. Give it a birth date, time and place and it computes a real chart, then interprets it.

Does it work with Claude or Cursor?

Yes, via MCP. Add the MCP server above to Claude Desktop, Cursor or Cline and the assistant gets compute_chart, read_section and list_sections as native tools.

Is it free?

Yes, with a per-IP rate limit. A bearer API key raises the limit for higher-volume use.

What ayanamsa and house system does it use?

Lahiri (Chitrapaksha) ayanamsa and whole-sign houses by default. The engine supports 12 ayanamsa systems and 8 house systems.