@pipeworx/knmi

Dutch national weather service open data — station observations, national radar precipitation, HARMONIE-AROME forecast runs and the gridded daily climate series — from the KNMI Data Platform Open Data API.

Part of Pipeworx — an MCP gateway connecting AI agents to 1679+ live data sources.

Tools

• knmi_datasets(search?, verify?, limit?) — the datasets worth calling, what each contains, how often it updates, and (checked live) its newest file.

• knmi_dataset_files(dataset, version, max_keys?, order_by?, sorting?, begin?, page_token?) — files in a dataset, newest first by default.

• knmi_file_url(dataset, version, filename) — a temporary signed download URL for one file.

Related MCP server: nl-opendata-mcp

Auth

Keyless in practice, keyed by design. Every endpoint needs an Authorization header, but KNMI publishes a shared anonymous key on its docs page and this pack ships it as the default, so callers need nothing. BYO override via _apiKey for a registered key.

The anonymous key is shared worldwide (50 requests/minute, 3000/hour) and KNMI rotates it on an expiry date printed on the docs page:

• A 429 is that shared bucket, not an outage. A registered key gets a dedicated 200 req/s.

• A 401/403 means the published key has rotated — read the "Anonymous key" section of https://developer.dataplatform.knmi.nl/open-data-api and update ANON_KEY. The tools refuse with wording that says so.

Register free at https://developer.dataplatform.knmi.nl/. A Pipeworx-held key would be PLATFORM_KNMI_KEY; declare platformKeyEnv in the pack manifest in the same change that lands the value, never before.

Whole-dataset downloads need a separate bulk key by email to opendata@knmi.nl. KNMI's fair-use policy treats aggressive polling as abuse; use their Notification Service for new-file push instead of tight loops.

Data sources

• GET /open-data/v1/datasets/{dataset}/versions/{version}/files — file listing.

• GET /open-data/v1/datasets/{dataset}/versions/{version}/files/{filename}/url — signed download URL.

• Docs: https://developer.dataplatform.knmi.nl/open-data-api

Things worth knowing:

• There is no /datasets listing endpoint — it answers 404. knmi_datasets carries a curated registry instead and verifies each entry live, so a retired dataset reports as retired rather than vanishing.

• Auth is checked before routing, so an unknown path also answers 401. You cannot probe the route table without a key.

• Dataset names are opaque and versioned as strings ("1.0", "2", "5").

• Actuele10mindataKNMIstations/2 still answers but stopped receiving files; 10-minute-in-situ-meteorological-observations/1.0 replaced it. A stale newest-file timestamp is the only signal, hence verify.

• Files are scientific binaries (NetCDF, HDF5, GRIB in tar), not JSON. HARMONIE runs are 1–3 GB each.

• Responses may carry an X-KNMI-Deprecation header ahead of a dataset retiring.

Verified

2026-09-17 — 11 datasets verified live; radar composite listing and a signed download URL both returned real payloads on the published anonymous key.

Quick Start

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

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

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/knmi/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 1679+ 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/knmi_datasets \
  -H 'Content-Type: application/json' \
  -d '{"search":"radar"}'

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

Standalone (no gateway account)

This package also runs as a local stdio MCP server — no Pipeworx account, no gateway round-trip:

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

Or run it directly to confirm it starts:

npx -y @pipeworx/mcp-knmi

It speaks MCP over stdin/stdout and answers initialize/tools/list/tools/call for only this pack's tools — none of the shared meta-tools the gateway connection above adds. Same source, same tools, no ask_pipeworx routing.

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 Knmi data" })

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

More

• Docs and guides

• pipeworx.io

License

MIT