34-tool Caelus MCP for validated astrology: charts, transits, Vedic, facts, sky view, synthetic.
Clean-room astrology computation monorepo. MIT, no Swiss Ephemeris code, no AGPL, no ephemeris files. Caelus computes ephemeris positions, charts, events, hellenistic timing techniques, Vedic methods, citable chart facts, sky-view image-prompt frames, and the MCP tools around them. Live at ephemengine.com.
| Path | npm | Description |
|---|---|---|
packages/caelus | caelus | TypeScript engine (~153 KB gzipped total, zero deps) |
packages/caelus-mcp | caelus-mcp | MCP server: charts, transits, synastry, events, eclipses |
packages/caelus-delineations-pd | — | Public-domain interpretation corpus + default validation set for interpret() |
packages/birth | caelus-birth | Birth time + place → UT (timezone and DST resolution) |
packages/wheel | caelus-wheel | React SVG chart wheel, zero runtime deps |
apps/web | — | Next.js site: playground, validation, edge /api/chart |
caelus-starter | — | Next.js starter app (separate repo) |
The Python reference engine and data-fitting pipeline live in python/;
they mint the coefficient data and golden fixtures and are not a runtime
dependency.
npm install
npm run build
npm test
npm run dev -w web
http://localhost:3000 — live chart in the browser.
Edge API: GET /api/chart?date=…&lat=…&lon=….
main — stable releasesdev — active developmentSource-derived launch command. Check the maintainer’s required arguments and credentials before running:
npx -y caelus-mcpMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-github-heavyblotto-caelus-mcp": {
"command": "npx",
"args": [
"-y",
"caelus-mcp"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup referencecaelus-mcpnpmio.github.heavyblotto/caelus-mcp works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.