Caelus is a remote MCP server that gives an AI agent 35 tools, among them aspect_patterns, chart_facts, chart_signature. It answers at https://www.ephemengine.com/api/mcp over streamable HTTP, and it listed its tools to an anonymous client, so no sign-in was needed for that. Our probes reached it 6 of 6 times since 11 September 2026; the last check, on 22 October 2026, succeeded.
34-tool Caelus MCP for validated astrology: charts, transits, Vedic, facts, sky view, synthetic.
Description as the publisher wrote it.
| Tool | What it does |
|---|---|
aspect_patterns | Classical aspect configurations in a chart: T-squares, grand trines, grand crosses, yods, kites, mystic rectangles, and stelliums by sign and by house. Each is a structured object with the participating bodies and the worst defining-aspect Inputs: date, lat, lon, house_system, zodiac |
chart_facts | A chart's validated facts as ranked, citable atoms for interpretation. Each fact has a stable id (e.g. "aspect:moon~neptune:conjunction"), the bodies it concerns, a salience score (luminaries, angular placements, the chart ruler, tight/hard Inputs: date, earliest, latest, when, anchors, calendars |
chart_signature | A chart's structural signature as plain counts: element, modality, angularity, quadrant, and hemisphere distributions over the bodies; the dominant element, modality, and most-occupied sign; and the classical chart ruler (the ruler of the A Inputs: date, lat, lon, house_system, zodiac |
composite | Relationship charts for two people: the midpoint composite (each body and angle is the shorter-arc midpoint of the two natal positions) and the Davison chart (a real chart cast for the midpoint in time and place). Each person needs date+lat Inputs: a, b, house_system, zodiac |
cosmic_weather | The mundane sky on a date: the active aspect configurations among the transiting planets (T-squares, grand trines, grand crosses, yods, kites, mystic rectangles, stelliums by sign), any planet stationing within a window, and whether the Moo Inputs: date, window_days, zodiac |
counterfactual_chart | A birth chart, perturbed — a 'what if'. Give a base chart (date+lat+lon) and an edit: `shift_time` (e.g. '1h', '-30m', 'P1D') moves the instant ("born an hour later"), `move_lat`+`move_lon` recompute at another place, and/or `set_longitudes Inputs: date, lat, lon, shift_time, move_lat, move_lon |
current_sky | The sky at a moment and place — not tied to any person. Use for "what's the sky/transits right now" or the chart of a non-birth event. Date defaults to now; lat/lon default to 0,0 (geocentric on the equator at the prime meridian), where hou Inputs: date, lat, lon, house_system, zodiac, separation |
dasha | Vedic dasha periods — planetary time-lord cycles started from the Moon's birth nakshatra. system selects Vimshottari (120-year, the standard), Yogini (36-year, eight yoginis), or Ashtottari (108-year). Returns the period timeline (mahadasha Inputs: date, lat, lon, system, target_date, levels |
dignities | Essential dignity and sect for the seven traditional planets at a moment and place. Per planet: its sign, any essential dignity (domicile/exaltation/detriment/fall), its weighted essential-dignity score (Lilly: rulership 5, exaltation 4, tr Inputs: date, lat, lon, zodiac |
directions | Primary (mundane) directions of the seven traditional planets to the four angles (MC, IC, Ascendant, Descendant), and optionally between the planets themselves. The diurnal rotation carries a body to the angle (or a promissor to a significa Inputs: date, lat, lon, key, max_years, include_mundane |
electional_search | Rank moments in a window for an electional aim. Samples the window and scores each instant by how closely a set of wanted body-to-body aspects is satisfied (tighter and applying aspects score higher), optionally penalizing a void-of-course Inputs: start, end, wanted, step_hours, avoid_void_moon, limit |
find_aspect_dates | Exact dates a transiting body makes an aspect, within a range: to a fixed longitude OR to another transiting body. Provide exactly one of target_lon / target_body. Includes retrograde re-hits. Body names are snake_case (mean_node, true_node Inputs: body, aspect, target_lon, target_body, start, end |
firdaria | Firdaria (firdariyyat): the Persian/medieval planetary time-lord periods. Life divides into nine major periods totalling 75 years — the seven planets (a day chart starts with the Sun, a night chart with the Moon) then the North and South No Inputs: date, lat, lon, target_date |
lots | The seven Hermetic lots (Arabic parts) — Fortune, Spirit, Eros, Necessity, Courage, Victory, Nemesis — cast from the Ascendant and reversing direction by sect (a chart is day when the Sun is above the horizon). Per lot: its longitude and zo Inputs: date, lat, lon, zodiac |
nakshatras | The nakshatra (one of the 27 lunar mansions of 13°20′) of each classical point on the sidereal zodiac: the seven traditional planets and the Ascendant (lagna). Per point: the nakshatra name, its pada (quarter, 1–4), the ruling planet (the V Inputs: date, lat, lon, zodiac |
natal_chart | A person's birth chart. Requires their exact birth date+time and birthplace (all three: date, lat, lon). Use this — not current_sky — whenever the question is about someone's natal/birth chart. Returns 13 bodies (sun–pluto, chiron, nodes) w Inputs: date, lat, lon, house_system, zodiac, separation |
parans | Parans (paranatellonta): co-angular bodies over the 24 hours from a date at a latitude — every pair of bodies simultaneously on one of the four angles (rising, culminating, setting, anti-culminating) within a stated tolerance. The relations Inputs: date, lat, bodies, tolerance_min, output |
planetary_hours | Planetary hours for a moment and place: the unequal hour in effect (its ruler, day/night, hour number 1-24, start/end UTC), the ruler of the planetary day, and the full 24-hour ruler sequence. Hours split the day (sunrise to sunset) and nig Inputs: date, lat, lon |
profections | Annual and monthly profections (a Hellenistic time-lord technique) at a target date. The natal Ascendant advances one whole sign per year of life; the profected sign's traditional ruler is the lord of the year, the single most important tim Inputs: date, lat, lon, target_date, zodiac |
progressions | Secondary progressions (day-for-a-year) and solar-arc directions of a natal chart to a target date. Returns, per body, the secondary-progressed longitude and the solar-arc-directed longitude, plus the solar arc itself. Longitudes only (no h Inputs: date, target_date, zodiac |
rectification_grid | Rectification sweep: ASC/MC at each step across a window of UTC hours on one date, with ASC sign-change times. Use when the birth time is unknown and you want candidate times. The sweep runs over window_start_hour..window_end_hour (UTC hour Inputs: date, lat, lon, window_start_hour, window_end_hour, step_minutes |
releasing | Zodiacal releasing (aphesis), the Hellenistic time-lord technique from Vettius Valens, released from a Lot (Spirit by default, or Fortune). From the Lot's sign, periods release sign by sign with planetary minor-year lengths on the 360-day-y Inputs: date, lat, lon, target_date, lot, max_level |
returns | Solar or lunar return: the instant(s) a body returns to its natal longitude within a window, plus the full return chart for the first one. The Sun returns about yearly (the solar-return chart for the year), the Moon about monthly. Return ch Inputs: date, lat, lon, body, search_start, search_end |
similar_skies | Find when the sky most resembled a reference moment. Builds a feature vector for the reference date's planetary configuration and scans a window for the closest matches by cosine similarity (1.0 = identical configuration). Answers 'when did Inputs: reference_date, start, end, step_days, limit |
sky_events | Sky events in a UTC date range: rise/set/meridian transits (need lat+lon+body), lunar phases (new/quarters/full), solar and lunar eclipses, stations (body turns retrograde/direct; needs body), zodiac degree crossings (needs body + target_lo Inputs: start, end, kinds, body, lat, lon |
sky_view | Where the visible bodies land in a framed photo of the sky, for an image prompt. Give a place, a moment, an aim (compass direction and altitude), a lens, and an image size; get each in-frame body's pixel position, apparent size, brightness, Inputs: date, lat, lon, elevation_m, azimuth, altitude |
sky_view_sequence | A time sequence of sky frames for an animation: the same place, aim, and lens stepped through time. Returns a compact per-frame timeline (instant, twilight, Sun/Moon altitude, Moon phase + bright-limb, whether the Milky Way is in frame) plu Inputs: date, lat, lon, azimuth, altitude, lens |
synastry | Compare two people's birth charts: inter-chart aspects with orbs, house overlays both ways, plus ranked citable fact atoms and a ready `brief` (synastry/composite ids for auditCitations). Each person needs date+lat+lon. House overlays alway Inputs: a, b, orb, zodiac |
synthetic_positions | Positions of every body in an authored synthetic system at one instant. Three body modes: `placement` (fixed longitude), `periodic` (uniform motion), `kepler` (constant elements). With `observer` set on the system, positions are geocentric/ Inputs: system, date, t_days |
synthetic_sky_view | Sky View for a mix of real and synthetic bodies: register the authored system on an ephemeral engine, then frame the visible sky like sky_view. Synthetic bodies can carry render attributes (sizeDeg, magnitude, color) that flow into the pixe Inputs: system, date, lat, lon, elevation_m, azimuth |
synthetic_validate | Check an authored synthetic celestial system for ill-defined inputs: duplicate body ids, non-positive periods, out-of-range eccentricity, or a dangling observer. Returns `impossible` and a list of problems — the same honesty pattern as comp Inputs: system |
transits | Transiting planets vs natal chart: aspects within orb (applying/separating), natal house per transiting body. Inputs: date, lat, lon, transit_date, orb, house_system |
vargas | Parashari divisional charts (vargas): the sign of each of the seven planets and the Ascendant in the requested D-charts — D1 rasi, D2 hora, D3 drekkana, D9 navamsa, D10 dasamsa, D12 dwadasamsa, D30 trimsamsa. Per point in each chart: the di Inputs: date, lat, lon, divisions, zodiac |
void_of_course | Void-of-course Moon at a moment: whether the Moon makes no further Ptolemaic aspect to a traditional planet (Sun..Saturn) before it leaves its current sign. Returns the Moon's sign, the UTC time it exits that sign, and the UTC time of its n Inputs: date, zodiac |
yogas | Vedic yogas (planetary combinations) on the sidereal rasi chart: the five Pancha Mahapurusha yogas (Ruchaka, Bhadra, Hamsa, Malavya, Shasha), Gajakesari, Budha-Aditya, and Chandra-Mangala; whether Kemadruma (the isolated-Moon yoga) is prese Inputs: date, lat, lon, zodiac |
Every block below points at https://www.ephemengine.com/api/mcp. Pick your client and copy.
claude mcp add --transport http caelus https://www.ephemengine.com/api/mcp
{
"mcpServers": {
"caelus": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://www.ephemengine.com/api/mcp"]
}
}
}{
"mcpServers": {
"caelus": {
"url": "https://www.ephemengine.com/api/mcp"
}
}
}{
"servers": {
"caelus": {
"type": "http",
"url": "https://www.ephemengine.com/api/mcp"
}
}
}{
"context_servers": {
"caelus": {
"url": "https://www.ephemengine.com/api/mcp"
}
}
}{
"mcpServers": {
"caelus": {
"serverUrl": "https://www.ephemengine.com/api/mcp"
}
}
}{
"mcpServers": {
"caelus": {
"url": "https://www.ephemengine.com/api/mcp"
}
}
}name: Caelus
version: 0.0.1
schema: v1
mcpServers:
- name: Caelus
type: streamable-http
url: https://www.ephemengine.com/api/mcp{
"mcpServers": {
"caelus": {
"httpUrl": "https://www.ephemengine.com/api/mcp"
}
}
}{
"mcpServers": {
"caelus": {
"type": "http",
"url": "https://www.ephemengine.com/api/mcp"
}
}
}{
"mcpServers": {
"caelus": {
"url": "https://www.ephemengine.com/api/mcp"
}
}
}goose://extension?url=https%3A%2F%2Fwww.ephemengine.com%2Fapi%2Fmcp&type=streamable_http&id=caelus&name=Caelus
It answered our last check on 22 October 2026 in 237 ms. Over 6 checks since 11 September 2026 it answered 6. Status here comes from Neuronto's own probes, not from the publisher.
35, as returned by the server's own tools/list on 14 September 2026: aspect_patterns, chart_facts, chart_signature, composite, cosmic_weather, counterfactual_chart, current_sky, dasha, and 27 more.
It answered our last check on 22 October 2026 in 237 ms. Over 6 checks since 11 September 2026 it answered 6.
Put the server under mcpServers in ~/.cursor/mcp.json with the URL https://www.ephemengine.com/api/mcp. The exact JSON is above, with the same setup for Claude Code, Claude Desktop, VS Code, Windsurf, Zed, Gemini CLI and the rest.
It listed its tools to an anonymous client, so reading the tool list needs no key. Individual tools can still ask for credentials in their own inputs.
Publisher: io.github.heavyblotto. Endpoint host: www.ephemengine.com. ARD identifier: urn:air:io.github.heavyblotto:mcp:caelus-mcp.
First indexed 10 September 2026. The tools are exactly what the server returned; nothing on this page
is inferred from its name. Ranking in Neuronto search is never for sale.