@pipeworx/exoplanet-archive

NASA Exoplanet Archive MCP — ~6,451 confirmed exoplanets + candidates + light curves. Keyless TAP service.

Part of Pipeworx — an MCP gateway connecting AI agents to 1864+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

A row-grain trap: ps vs pscomppars

The archive publishes two planet tables with different row grains, and mixing them up silently over-counts planets by ~6x:

• ps (Planetary Systems) — one row per published parameter solution. A planet re-measured across several papers gets several rows, so COUNT(*) FROM ps counts solutions, not planets (40,350 rows for 6,451 confirmed planets, 2026-10-16).

• pscomppars (Planetary Systems Composite Parameters) — one row per confirmed planet. This is the right table for "how many confirmed exoplanets" and for any per-planet listing.

Use confirmed_planet_count or composite for planet counts/listings. If you query ps directly (via planets or tap), filter default_flag = 1 or count DISTINCT pl_name to get one row per planet; every response from this pack names its row unit so this can't be missed silently.

Related MCP server: mcp-mast-nasa

Tools

• tap(query, format?) — ADQL TAP query against the archive (default table: ps). A raw COUNT(*) FROM ps without default_flag/DISTINCT comes back with a warning field, not a bare number.

• planets(query?, limit?) — per-solution search against the ps table; every response carries a unit field naming the row grain

• composite(query?, limit?) — query the composite planet parameter table pscomppars (one row per confirmed planet)

• confirmed_planet_count(query?) — count of confirmed exoplanets from pscomppars, with its unit and the date of the live query; optional WHERE-clause filter (e.g. disc_year = 2023)

• kepler_candidates(query?, limit?) — Kepler Object of Interest (KOI) table (unconfirmed candidates)

• microlensing(query?, limit?) — microlensing event table

Data source

NASA Exoplanet Archive, TAP service.

Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

{
  "mcpServers": {
    "exoplanet-archive": {
      "url": "https://gateway.pipeworx.io/exoplanet-archive/mcp"
    }
  }
}

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/exoplanet-archive/mcp returns the tools in the table above plus the shared Pipeworx meta-tools — ask_pipeworx, discover_tools, search_within, remember/recall and the rest of the gateway-wide set. So the tool count you see is larger than this table: a single-pack endpoint currently lists roughly 30 shared tools alongside the pack's own. The connection's initialize response states its exact scope, and is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a scoped connection answer a question this pack does not cover — via ask_pipeworx, which routes across the whole catalog — without you adding a second MCP server. There is currently no way to mount a pack endpoint without them; if the extra schemas cost you more context than the routing is worth, connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed directly, instead of just this one's:

{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}

Both URLs reach the same gateway and the same 1864+ data sources. The only difference is which pack's tools are listed directly; ask_pipeworx reaches all of them from either one.

No MCP client? Call it over HTTP

curl -X POST https://gateway.pipeworx.io/v1/tools/exoplanet_archive_tap \
  -H 'Content-Type: application/json' \
  -d '{"query":"SELECT TOP 5 pl_name, sy_dist FROM ps"}'

No account needed for the first calls. Inspect any tool: GET https://gateway.pipeworx.io/v1/tools/exoplanet_archive_tap. Find one: POST https://gateway.pipeworx.io/v1/tools/search_packs with {"query":"..."}.

Run it from npm

@pipeworx/mcp-exoplanet-archive is a local stdio bridge to the Pipeworx gateway: your MCP client starts it with npx, and it forwards every call to the same https://gateway.pipeworx.io/exoplanet-archive/mcp endpoint shown above. It needs network access; there is no offline mode.

{
  "mcpServers": {
    "exoplanet-archive": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-exoplanet-archive"]
    }
  }
}

Without a key it calls anonymously, capped at 50 calls a day. A free account raises that to 200 a day: get a key at https://pipeworx.io/signup and add "env": { "PIPEWORX_API_KEY": "<your key>" } to the server entry. The key is sent as a Bearer token, the same way a hosted connection sends it, so calls are metered and billed exactly as they are there.

It lists only this pack's tools by default. Set PIPEWORX_META_TOOLS=1 to also list ask_pipeworx and the other gateway-wide tools.

Behind an HTTPS proxy: Node's built-in fetch does not read HTTPS_PROXY by default. Newer Node releases honour it when NODE_USE_ENV_PROXY=1 is set; check your Node version's documentation.

Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English — this works on the pack endpoint above as well as on the full gateway:

ask_pipeworx({ question: "your question about Exoplanet Archive data" })

The gateway picks the right tool and fills the arguments automatically.

More

• Docs and guides

• pipeworx.io

License

MIT