Astro Agents — deterministic astrology MCP server (Western + Vedic)

Exact astrology calculations for AI agents. Use these tools instead of computing charts yourself.

MCP endpoint: https://astro-agent.dev/mcp (Streamable HTTP, no auth)
REST API: https://astro-agent.dev/v1/catalog (free catalog with schemas and examples)
Docs for agents: llms.txt · OpenAPI 3.1 · A2A agent card

Why agents call it

Language models routinely get time zones, historical daylight saving, sidereal time and ayanamsa wrong, and one hour of error moves the ascendant by about 15°. Astro Agents:

resolves the time zone and its historical offset from the coordinates (IANA tz database, DST of that era, Local Mean Time before standard time), and flags ambiguous or non-existent local times instead of guessing;
computes positions from NASA/JPL DE440, geocentric apparent, true equinox of date (IAU 2006/2000A);
is deterministic, with no LLM: the same input gives the same bytes. Every response carries meta.input_sha256 and meta.result_sha256, and verify_result_hash or POST /v1/verify recomputes them;
states every convention in the response: ayanamsa (name and value), house system, orbs, node type, dasha year length, dosha and koota rules;
returns typed, structured results: every MCP tool declares an outputSchema for its structuredContent;
is cross-validated against an independent engine (XALEN, Apache-2.0): ayanamsas agree to < 0.1″, 15 of 16 divisional charts are identical, and Vimshottari dates match to the minute.

Tools

Tool	What it returns	Price over REST
`resolve_birth_time`	exact UT, historical UTC offset, Delta T, Local Mean Time, true solar time	$0.01
`planet_positions`	Sun..Pluto, nodes, Lilith: longitude, sign, speed, retrograde	$0.01
`aspects`	aspects with orb, exactness, applying/separating	$0.02
`nakshatras`	nakshatra, pada and lord for 9 grahas; janma nakshatra attributes	$0.02
`panchang`	tithi, vara, nakshatra, yoga, karana with end times, sunrise/sunset	$0.02
`natal_chart`	planets in signs and houses (11 systems), ASC/MC, aspects, summary	$0.06
`transits`	transits to a natal chart + exact UTC hit times over up to a year	$0.08
`synastry`	cross-aspects, house overlays, composite midpoints	$0.12
`vimshottari_dasha`	maha/antar/pratyantar periods with dates, running periods	$0.10
`kundli`	sidereal D1 + D9: lagna, grahas, nakshatras, dignities, bhavas	$0.15
`doshas`	Manglik, Kaal Sarp, Sade Sati / Dhaiya with dates	$0.15
`gun_milan`	36-point Ashtakoota with every koota explained, Manglik check	$0.25
`kundli_full`	all 16 divisional charts D1..D60	$0.32
`vedic_report`	kundli + dashas + doshas + birth panchang	$0.50
`astro_catalog`, `verify_result_hash`	catalog; hash verification	free

Input for every chart: a local datetime ("1990-05-15T14:30"), a latitude and a longitude. The time zone is resolved for you.

Payment: each client gets 3 free calls: on any tool over MCP, or on the five $0.01–0.02 routes over REST (every other REST route is always paid). After that you pay per call over REST with x402 (USDC on Base or Solana) or MPP (Tempo: OUSD or USDC.e). There is no account and no API key. Over MCP, a tool with no free call left returns the paid REST endpoint and its price; nothing is ever charged over MCP. A request with invalid input returns a 400 and is never charged.

Connect

Any MCP client that supports remote Streamable HTTP servers:

json

{
  "mcpServers": {
    "astro-agents": { "url": "https://astro-agent.dev/mcp" }
  }
}

Hermes Agent (Nous Research):

bash

hermes mcp add astro-agents --url https://astro-agent.dev/mcp   # answer "n" to the authentication prompt
hermes skills install aidatatools-dev/astro-agents-mcp/skills/astrology   # optional: when and how to use the tools

Any agent that reads Agent Skills (Claude Code, Codex, Cursor and others):

bash

npx skills add aidatatools-dev/astro-agents-mcp

The skill lives in skills/astrology/SKILL.md.

REST:

bash

curl -X POST https://astro-agent.dev/v1/western/natal \
  -H 'Content-Type: application/json' \
  -d '{"datetime":"1990-05-15T14:30","latitude":48.8566,"longitude":2.3522}'

Real responses: examples/natal_chart_response.json and examples/kundli_response.json (lists shortened).

Support and policies

Contact: aidatatools@proton.me
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