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Astral Mcp

davidmosiah/astral-mcp

This is a local-first astrology engine that computes natal charts, transits, synastry, and moon phases with no API key required. Every chart runs through dual-engine verification: one ephemeris calculates, another cross-checks, and disagreements beyond 0.01° get flagged. You get ten tools including natal chart generation, current and upcoming transits, two-chart compatibility scoring, and geocoded birthplace lookup via OpenStreetMap. It ships with privacy modes to control payload size, supports seven house systems, and returns structured JSON with planets, aspects, chart signatures, and retrogrades. Install with npx and call it immediately. Built by the Alkhemia app developer, tested across 65 years of birth data.

tools: 10
transport: STDIO
env vars: 4
last updated: Jun 7, 2026

Tools

10 tools

Public tool metadata for what this MCP can expose to an agent.

astral_compute_natal_chartfull natal chart, precision-audited by default

full natal chart, precision-audited by default

No parameter schema in public metadata yet.

astral_current_transitscurrent + upcoming transits to a chart, with moon phase

current + upcoming transits to a chart, with moon phase

No parameter schema in public metadata yet.

astral_synastrycompare two charts (harmony / chemistry / communication / growth)

compare two charts (harmony / chemistry / communication / growth)

No parameter schema in public metadata yet.

astral_moon_phasemoon phase, sign and illumination for any date

moon phase, sign and illumination for any date

No parameter schema in public metadata yet.

astral_search_birthplacegeocode a place to latitude / longitude / timezone

geocode a place to latitude / longitude / timezone

No parameter schema in public metadata yet.

astral_demoworked example chart, no input needed

worked example chart, no input needed

No parameter schema in public metadata yet.

astral_capabilitieswhat this server supports and what it doesn't

what this server supports and what it doesn't

No parameter schema in public metadata yet.

astral_data_inventorydata domains and recommended first calls

data domains and recommended first calls

No parameter schema in public metadata yet.

astral_agent_manifestinstall + usage rules for agents

install + usage rules for agents

No parameter schema in public metadata yet.

astral_connection_statushealth check via a sample chart + dual-engine audit

health check via a sample chart + dual-engine audit

No parameter schema in public metadata yet.

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Configuration

ASTRAL_MCP_TRANSPORT

Transport to run. Defaults to stdio. Set to http to expose a streamable HTTP endpoint instead.

ASTRAL_MCP_HOST

Host to bind when ASTRAL_MCP_TRANSPORT=http. Defaults to 127.0.0.1.

ASTRAL_MCP_PORT

Port to bind when ASTRAL_MCP_TRANSPORT=http. Defaults to 3000.

ASTRAL_MCP_ALLOWED_ORIGIN

Allowed CORS origin for the HTTP transport. Defaults to the bound host:port.

Readme

Astral MCP

Astral MCP — precision-audited astrology for AI agents

Give your AI agent real astrology — natal charts, transits, synastry & moon phases.
Computed locally, cross-checked by two independent ephemerides. No API key, no account.

View the full README on GitHub

Details

Repository: github.com/davidmosiah/astral-mcp
Website: github.com/davidmosiah/astral-mcp
Package: astral-mcp
Transport: STDIO
Registry: MCP registry, active