NASA-validated computed planetary positions for your AI: 19 astrology tools, never hallucinated.
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Config is the same across clients — only the file and path differ.
{
"mcpServers": {
"llmastro": {
"args": [
"-y",
"@cosmosos/mcp-ephemeris"
],
"command": "npx"
}
}
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The real sky, for your AI. An MCP server that gives any assistant (Claude, Cursor, agents) computed planetary positions — never guessed — powered by the Swiss Ephemeris engine, and validated against JPL Horizons (NASA) to under one arcsecond.
Run this in your terminal to verify the server starts. Then let us know if it worked — your result helps other developers.
npx -y 'pnpm' 2>&1 | head -1 && echo "✓ Server started successfully"
After testing, let us know if it worked:
Five weighted categories — click any category to see the underlying evidence.
pnpm: Path traversal in configDependencies env lockfile allows symlink creation outside node_modules/.pnpm-config
## Summary `pnpm` accepts package names from the env lockfile `configDependencies` section and uses those names directly when creating config dependency symlinks under `node_modules/.pnpm-config`. A malicious repository can commit a crafted `pnpm-lock.yaml` whose env-lockfile document contains a traversal-shaped config dependency name such as `../../PWNED_CFGDEP`. During `pnpm install`, pnpm installs the config dependency and creates a symlink at a path derived from that name. In local testin
pnpm: `patch-remove` could delete project-selected files outside the patches directory
## Summary The `patch-remove` deletion-scope issue tracked as GHSA-72r4-9c5j-mj57 / CAND-PNPM-030 has been addressed in pnpm. A crafted patch entry could resolve outside the configured patches directory and cause `pnpm patch-remove` to delete an arbitrary reachable file. This patch validates the configured directory and every resolved target before unlinking anything, then deletes the final directory entry without following it. ## Security boundary - Traversal and absolute paths that resolve
pnpm: Hoisted install imports lockfile alias outside node_modules
## Summary The hoisted dependency alias issue tracked as GHSA-fr4h-3cph-29xv / CAND-PNPM-059 has been addressed in both pnpm and pacquet. A crafted lockfile alias could be joined directly under a hoisted `node_modules` directory. Traversal aliases could escape that directory, while reserved aliases such as `.bin` or `.pnpm` could overwrite pnpm-owned layout. This patch validates package-name semantics and path containment before graph insertion or filesystem work. ## Security boundary - The
pnpm: `stage download` writes outside its destination directory via manifest name/version traversal
## Summary The staged-tarball filename traversal reported as GHSA-v23m-ccfg-pq9h / CAND-PNPM-038 is fixed on `main` by [pnpm/pnpm#12303](https://github.com/pnpm/pnpm/pull/12303), merged as `65443f4bdf1f0db9c8c7dc58fee25252607e9234`. Before the fix, `pnpm stage download` derived a local filename from registry-controlled package name and version fields. A crafted manifest could escape the selected download directory and overwrite another reachable file. The merged fix validates both fields, deri
pnpm: Reserved bin name deletes PNPM_HOME during global remove
<details> <summary>Maintainer Action Plan</summary> ## Maintainer Action Plan This report is ready to review with the shared patch branch. Start with the PR and the expected fixed behavior, then use the detailed exploit narrative below only if you want to replay the original path. - Advisory: `CAND-PNPM-085` / `GHSA-4gxm-v5v7-fqc4` - Advisory URL: https://github.com/pnpm/pnpm/security/advisories/GHSA-4gxm-v5v7-fqc4 - Shared patch PR: https://github.com/pnpm/pnpm-ghsa-j2hc-m6cf-6jm8/pull/1 - S
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The real sky, for your AI. An MCP server that gives any assistant (Claude, Cursor, agents) computed planetary positions — never guessed — powered by the Swiss Ephemeris engine, and validated against JPL Horizons (NASA) to under one arcsecond.
Cardinal rule: the LLM never computes. This server is a facade over an ephemeris engine. The model interprets; the sky is a fact.
(Version française : https://llmastro.com/notre-moteur)
Open Settings → Developer → Edit Config, then add:
{
"mcpServers": {
"llmastro": {
"command": "npx",
"args": ["-y", "@cosmosos/mcp-ephemeris"]
}
}
}
Fully quit Claude Desktop (system tray) and relaunch it. Then ask: "What's the moon phase today?" — Claude calls the server and answers from genuinely computed positions.
Cursor / Windsurf / others: add the same llmastro entry
(command: npx, args: ["-y", "@cosmosos/mcp-ephemeris"]) to your client's MCP
configuration.
19 tools, all backed by the same server-side computed engine.
| Tool | Input | Output |
|---|---|---|
get_planet_positions | datetime (ISO UTC) | ecliptic positions of all bodies (sign, degree, retro) |
get_moon_phase | datetime (ISO UTC) | moon phase, illumination %, description |
get_current_sky | latitude, longitude | the sky right now (current transits) for a place |
get_aspects | datetime (ISO UTC) | grid of major + minor aspects between bodies |
| Tool | Input | Output |
|---|---|---|
get_natal_chart | birth + zodiac (tropical/sidereal), houseSystem (7 systems) | full chart: houses, aspects, ASC/MC, moon phase, Hermetic Lots |
get_transits | birth + optional datetime | transit→natal aspects, sorted by orb |
get_synastry | two births | inter-chart aspects + harmony/tension summary |
get_composite_chart | two births | midpoint composite chart |
get_secondary_progressions | birth + targetDate | progressed positions ("a day for a year") |
get_solar_return | birth + year (+ optional place) | instant + chart of the solar return |
get_lunar_return | birth + optional after | instant + chart of the next lunar return |
| Tool | Input | Output |
|---|---|---|
get_ingresses | body, start, end | sign-change dates (retrograde-robust) |
get_retrograde_windows | body, start, end | retrograde/direct stations over the range |
get_eclipse_details | datetime, kind | magnitude, obscuration, Saros of a known eclipse (swisseph) |
get_next_eclipse | from, kind, optional backward | next/previous eclipse: maximum, type, contacts (swisseph) |
| Tool | Input | Output |
|---|---|---|
get_astrocartography | datetime (ISO UTC) | planetary MC/IC lines + parans (crossings) |
get_life_path | date (YYYY-MM-DD) | life-path number (numerology) |
get_engine_diagnostic | — | active engine, native addon load status, real precision |
validate_against_horizons | datetime, optional bodies | delta of our positions vs JPL Horizons (NASA) in arcseconds — network required |
(swisseph) = requires the native Swiss Ephemeris addon; returns null on the AstraCore fallback.
Under Swiss Ephemeris, positions match the world reference JPL Horizons (NASA) to under one arcsecond (measured 2026-07-19):
| Body | Difference vs NASA |
|---|---|
| Sun | 0.2″ |
| Moon | 1.5″ |
| Jupiter | 0.1″ |
| Pluto | 0.4″ |
Check it yourself with the validate_against_horizons tool.
Computation is routed by the ASTRO_ENGINE variable:
swisseph (default) — Swiss Ephemeris, native addon, sub-arcsecond
precision. Compiles automatically wherever a C++