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caelus-mcp

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34-tool Caelus MCP for validated astrology: charts, transits, Vedic, facts, sky view, synthetic.

v0.24.1 · active · repository · descriptor JSON · versions

An agent can connect right now, no human step.Remote endpoint, no authentication, reachable on the last probe.
Quality72needs work
Trust91of 100
Uptime, 30 days100%
Latency p50282 ms

Connect

8 clients · secrets stay placeholders
{
  "mcpServers": {
    "caelus-mcp": {
      "type": "http",
      "url": "https://www.ephemengine.com/api/mcp"
    }
  }
}
claude mcp add --transport http caelus-mcp https://www.ephemengine.com/api/mcp
[mcp_servers.caelus-mcp]
url = "https://www.ephemengine.com/api/mcp"
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "caelus-mcp": {
      "type": "remote",
      "url": "https://www.ephemengine.com/api/mcp",
      "enabled": true
    }
  }
}
{
  "mcpServers": {
    "caelus-mcp": {
      "type": "http",
      "url": "https://www.ephemengine.com/api/mcp"
    }
  },
  "deeplink": "cursor://anysphere.cursor-deeplink/mcp/install?name=caelus-mcp&config=eyJ0eXBlIjoiaHR0cCIsInVybCI6Imh0dHBzOi8vd3d3LmVwaGVtZW5naW5lLmNvbS9hcGkvbWNwIn0%3D"
}
{
  "servers": {
    "caelus-mcp": {
      "type": "http",
      "url": "https://www.ephemengine.com/api/mcp"
    }
  }
}
{
  "mcpServers": {
    "caelus-mcp": {
      "httpUrl": "https://www.ephemengine.com/api/mcp"
    }
  }
}
extensions:
  "caelus-mcp":
    enabled: true
    name: "caelus-mcp"
    type: streamable_http
    uri: "https://www.ephemengine.com/api/mcp"
    timeout: 300

Quality 72 / 100needs work

protocol75 · weight 25
  • warn
    protocol.modernnewest supported version is 2025-11-25; 2026-07-28 not supported, older versions are deprecated until 2027-07-28
  • n/a
    protocol.statelessonly applies to 2026-07-28 servers
  • pass
    protocol.transportstreamable HTTP
  • n/a
    protocol.list_ttlonly applies to 2026-07-28 servers
authorizationn/a · weight 15
  • n/a
    auth.prm, auth.as_metadata, auth.cimdno remote uses OAuth
  • n/a
    auth.secret_in_urlno templated URL
tool hygiene57 · weight 30
  • pass
    tools.descriptionsevery tool has a description
  • warn
    tools.description_length1 tools have descriptions over 1,024 characters, which crowds the context
  • pass
    tools.schemasevery tool has an object input schema
  • fail
    tools.annotationsno tool declares readOnlyHint or destructiveHint, so clients cannot tell safe calls from risky ones
  • fail
    tools.directory_hintsno tool declares all four of readOnlyHint, destructiveHint, idempotentHint and openWorldHint; missing: sky_view_sequence (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); composite (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); cosmic_weather (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); …
  • warn
    tools.token_costabout 16,810 tokens to load every tool
  • pass
    tools.api_dumptools are not a one-to-one API dump
stability100 · weight 15
  • pass
    stability.changesno tool changes in 30 days
  • pass
    stability.rug_pullno tool changed its meaning under the same name
dependencies67 · weight 15
  • pass
    deps.known_vulnsno known advisory in 99 resolved packages
  • fail
    deps.mcp_sdk_version@modelcontextprotocol/sdk 1.30.1 has 1 known advisory (GHSA-6qxp-vccf-f47h); update @modelcontextprotocol/sdk to 1.31.0 or later
  • pass
    deps.resolvable[email protected] resolved: 99 packages

35 tools, about 16,810 tokens to load them all · tool set 9c5fb641c69a · checked 2026-10-19 10:20 UTC

Tool changes

No tool definition changes recorded. A server's first observation is its baseline; later probes record what changes.

Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed. How it is computed.

Trust 91 / 100

provenance80
liveness100
freshness85
hygiene100

+repository +namespace-matches-repo +reachable +uptime-100% ~updated-65d-ago

Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed. How it is computed.

Dependencies

[email protected] npm98 dependencies, resolved · MCP SDK @modelcontextprotocol/sdk 1.30.1 · advisories checked 2026-10-19

advisoryseveritypackagefixed in
GHSA-6qxp-vccf-f47hMCP TypeScript SDK: OAuth client could send credentials to an authorization server chosen by the MCP serverhigh@modelcontextprotocol/[email protected]MCP SDK, directfixed in 1.31.0

Dependency graphs from deps.dev; advisories from OSV.dev, including the GitHub Advisory Database and the PyPI Advisory Database; all CC BY 4.0. The graph is what a clean install of this version resolves today; nothing was installed or run. How it is checked.

Endpoints

remoteauthreachableuptime 30dp50protocollast ok
https://www.ephemengine.com/api/mcp streamable-httpnoneyes100%282 ms2025-11-252026-10-19
packageregistryversionruntimesecrets
caelus-mcpnpm0.24.1–

Tools (35)

aspect_patternsClassical 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 orb; T-squares and yods also name the apex, stelliums their sign or house. Reported patterns are maximal — a grand cross hides the T-squares it contains, a kite its grand trine. Pure geometry (engine orbs plus a quincunx for yods), no interpretation. Needs date, lat, lon.
chart_factsA 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 aspects, configurations rank high), and a plain-language statement. Facts span placements, aspects, configurations, the structural signature, dispositors and receptions, a body's tight conjunction with a bright fixed star (e.g. "star:jupiter:Sirius"), and the Part of Fortune and Spirit (e.g. "lot:fortune"). Read the facts, write the interpretation in your own words, and cite the [id] each statement rests on — do not introduce facts not listed. Returns the ranked facts plus a ready-to-interpret `brief`. By default a real birth chart: pass date+lat+lon. The chart's grounding is first-class via `realm` (what it is: observed/forecast/fictional/mythic/archetypal/…) and the time: an exact `date`, an uncertain `earliest`+`latest` range (the brief then frames it as provisional and trusts the Moon/angles/houses less), `constraints` for an archetypal chart with no time (synthesized via the compiler), or a full structured `when` (relative-to-another-event or a narrative calendar). A `when` of kind `relative` looks its `anchorId` up in `anchors` (a map of id → UTC instant supplied in the request). Omit lat+lon for a placeless chart (nominal houses).
chart_signatureA 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 Ascendant's sign). Counts only, no interpretation — a compact summary for emphasis and comparison. Needs date, lat, lon.
compositeRelationship 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+lon.
cosmic_weatherThe 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 Moon is void of course. A 'cosmic weather' snapshot; no birth chart or location needed.
counterfactual_chartA 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` moves bodies to new ecliptic degrees ("Mars in the next sign"). Returns the diff vs the original: bodies that changed sign or house, aspects gained or lost, and angles that changed sign. A time/place edit rotates the houses and angles while planets stay put; a longitude splice moves only those bodies and recomputes their aspects.
current_skyThe 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 houses and ASC/MC are nominal — pass a real location if houses matter. For a specific person's birth chart use natal_chart instead. Returns positions, houses, retrogrades, aspects.
dashaVedic 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 → antardasha) with UTC start/end, the balance of the first period at birth, and — when target_date is given — the lords active then (Vimshottari also gives the pratyantardasha). Sidereal; Lahiri by default. Needs the birth time and place.
dignitiesEssential 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, triplicity 3, term 2, face 1; detriment -5, fall -4) with a peregrine flag, its planetary sect (diurnal/nocturnal, null for Mercury), and whether it is in sect given a day or night chart. The chart is day when the Sun is above the horizon — so lat+lon are required.
directionsPrimary (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 significator); the arc of rotation, converted by a time key (Naibod 0.9856473°/yr by default, or Ptolemy 1°/yr), gives the age of the direction. Returns the directions within max_years, sorted by age, each with its arc, age in years, and UTC date. With include_mundane, also returns the planet-to-planet (promissor → significator) directions. Circumpolar bodies have no Ascendant/Descendant directions. Needs the birth time and place; equatorial, so zodiac is irrelevant.
electional_searchRank 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 Moon. Returns the top moments with the aspects that matched. Body-to-body only; for aspects to the angles, compute the chart at a candidate moment.
find_aspect_datesExact 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).
firdariaFirdaria (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 Nodes — each planetary period split into seven sub-periods. Returns the full timeline (each period and sub-period with UTC start/end) and, when target_date is given, the major and sub lord active then. Sect is taken from the birth chart, so lat+lon are required; pure time arithmetic, no zodiac.
lotsThe 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 zodiacal position. Lots are anchored to the Ascendant, so an exact time and lat+lon are required. Fortune and Spirit are mirror images about the Ascendant. Tropical by default.
nakshatrasThe 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 Vimshottari lord), and degrees into the nakshatra. The Moon's nakshatra (janma nakshatra) anchors the Vimshottari dasha. Sidereal by definition; Lahiri ayanamsa by default. Needs the birth time and place for the Ascendant.
natal_chartA 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) with sign, house, retrograde, speed; ASC/MC; cusps; major aspects with orb, applying/separating phase, and strength (1=exact). Vs Swiss Ephemeris (1850–2150): Sun–Saturn ≤1″, Uranus ≤1.9″, Neptune ≤4.6″, Moon ≤2.5″, Pluto ≤3.4″ (Chebyshev pack), Chiron ≤1″, mean node ≤1″, true node ≤ 1′ vs SE's built-in ephemeris.
paransParans (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 relationship behind Brady's fixed-star parans, computed for the moving bodies; pure positional astronomy over the validated rise/set/transit times. Longitude-independent: latitude alone fixes the geometry, so only lat is needed. Date defaults to now.
planetary_hoursPlanetary 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 night (sunset to next sunrise) into twelve each; the day ruler is the weekday ruler and the hours follow the Chaldean order. Needs lat+lon. Returns available:false above the polar circles when the Sun does not rise or set that day.
profectionsAnnual 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 time-lord for that year. Returns the age in years, the month within the profection year, and the annual and monthly profected sign (with its whole-sign house from the natal Ascendant and its lord). Needs the birth time and place for the Ascendant.
progressionsSecondary 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 houses), so no birthplace is needed.
rectification_gridRectification 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 hours of the given date); the date's time portion is ignored.
releasingZodiacal 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-year convention; each level is a twelfth of the one above (L1..L4), and a loop back to the starting sign looses the bond, jumping once to the opposite sign (+6). Returns the timeline down to max_level over the horizon and, when target_date is given, the L1..L4 lords active then. Anchored to the natal Lot, so an exact time and lat+lon are required.
returnsSolar 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 chart is cast for the return moment at return_lat/return_lon (defaults to the birthplace; pass the current/relocated place for a relocated return).
similar_skiesFind 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 the sky last look like this?' for transit echoes and historical analogues. Returns the top matches with their similarity, highest first.
sky_eventsSky 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_lon). Solar eclipses report global circumstances (type, magnitude, gamma) plus the greatest-eclipse location and path width; add lat+lon to also get local circumstances (type seen, magnitude, obscuration, contact times C1-C4). Lunar eclipses report type and magnitude; add lat+lon to learn whether the Moon is above the horizon there. Times to the second vs Swiss Ephemeris (stations to ~1 min: ill-conditioned by nature). Range <= 370 days.
sky_viewWhere 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, the Moon's phase orientation, a sky-state summary (twilight, limiting magnitude, horizon row), the bright bodies just outside the frame, a ready-to-use prompt, and a machine-readable `renderPlan` (a body-free background-plate prompt plus the computed layers to composite locally, for a hybrid render pipeline). Caelus computes the geometry and photometry; it does NOT render the image. For "at sunset", first find the set time with sky_events, then pass it as date.
sky_view_sequenceA 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) plus the fixed celestial pole and the sky's sidereal rotation per frame. Each frame's full pixel-accurate spec comes from calling sky_view at that instant; this tool plans the timeline. Use for sunset-to-night transitions, star-trail planning, or Moon-phase progressions.
synastryCompare 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 always use Placidus (not configurable here).
synthetic_positionsPositions 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/apparent from that body (outer bodies can show retrograde). Pass `t_days` for abstract day units, or `date` (UT ISO) when body `epoch` values are Julian Days. Returns speed and retrograde per body.
synthetic_sky_viewSky 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 pixel spec and prompt. Real Sun/Moon/planets stay for twilight and context unless omitted from `bodies`.
synthetic_validateCheck 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 compileForm.
transitsTransiting planets vs natal chart: aspects within orb (applying/separating), natal house per transiting body.
vargasParashari 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 divisional sign and the division number within the rasi. The navamsa (D9) is the most consulted after the rasi. Sidereal; Lahiri by default. Needs the birth time and place for the Ascendant.
void_of_courseVoid-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 next perfecting aspect (null when none remains -- i.e. void). Tropical by default.
yogasVedic 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 present; the raja yogas (a kendra lord associating with a trikona lord) and dhana (wealth) yogas, each as the lord pair and how they associate (conjunction, aspect, or exchange); and the chart's yogakarakas (a planet ruling both a kendra and a trikona). Sidereal; Lahiri by default. Needs the birth time and place.

Schemas: list_tools.

Similar MCP servers

Official server.json
{
  "name": "io.github.heavyblotto/caelus-mcp",
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
  "remotes": [
    {
      "url": "https://www.ephemengine.com/api/mcp",
      "type": "streamable-http"
    }
  ],
  "version": "0.24.1",
  "packages": [
    {
      "version": "0.24.1",
      "transport": {
        "type": "stdio"
      },
      "identifier": "caelus-mcp",
      "registryType": "npm"
    }
  ],
  "repository": {
    "url": "https://github.com/heavyblotto/caelus",
    "source": "github"
  },
  "description": "34-tool Caelus MCP for validated astrology: charts, transits, Vedic, facts, sky view, synthetic."
}