@pipeworx/stats-nz

New Zealand official statistics (Aotearoa Data Explorer) — search Stats NZ's 911 published datasets by keyword and pull their observations, covering the 2013/2018/2023 censuses, LEED earnings, business demography, population estimates and projections, household expenditure, corrections and justice.

Part of Pipeworx — an MCP gateway connecting AI agents to 1857+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

Tools

• statsnz_datasets({ query, limit, offset }) — keyless. Keyword-search all 911 datasets; returns dataset id, full title, description, agency, version.

• statsnz_smoking_by_region({ region?, year?, _apiKey }) — Census smoking status (regular smoker / ex-smoker / never smoked regularly) by regional council for 2006, 2013, 2018 and 2023, with counts and percentages of people whose status was stated. Census self-report, not the Ministry of Health NZ Health Survey.

• statsnz_observations({ dataset, key, agency, version, startPeriod, endPeriod, lastNObservations, _apiKey }) — period/value pairs with their dimension labels. A too-wide unfiltered query is auto-narrowed to totals and flagged in narrowed (see Traps).

• statsnz_resources({ dataset, agency, version, includeCodes, maxCodesPerList, _apiKey }) — dimensions in key order, time dimension, measure, and the code lists that turn a key like 1.2.Q into something readable.

Related MCP server: ONS + Nomis MCP server

Auth

Platform key PLATFORM_STATSNZ_KEY (in the encrypted keystore since 2026-09-18) with BYO override via ?_apiKey=; sent upstream as an Ocp-Apim-Subscription-Key header. Callers need no key of their own. Free subscription at https://portal.apis.stats.govt.nz/ — sign up, then subscribe to the Aotearoa Data Explorer API product.

statsnz_datasets additionally works with no key at all.

Data sources

• https://api.data.stats.govt.nz/rest/dataflow/all/all/latest — dataset catalogue (keyless).

• https://api.data.stats.govt.nz/rest/data/{agency},{dataset},{version}/{key} — observations (keyed).

• https://api.data.stats.govt.nz/rest/datastructure/{agency}/{dataset}/{version}?references=all — structure + code lists (keyed).

Traps

• The catalogue is SDMX-ML now, whatever you ask for. /rest/dataflow/all/all/latest served SDMX-JSON until 2026-09-18 and now serves application/vnd.sdmx.structure+xml; version=2.1 on every Accept header tried — structure+json;version=1.0, bare application/json, structure+json;version=2.0 — keyed and keyless alike. res.json() on it throws Unexpected token '<', "<?xml vers", which classifies as upstream_down and reads like an outage rather than a format change. The pack parses the XML. This is endpoint-specific: /rest/datastructure/… still answers structure+JSON, so don't convert that one too.

• The flowRef commas must stay literal — encoding them is a silent zero. The data path is /rest/data/{agency},{dataset},{version}/{key}. Their Azure APIM does not percent-decode path segments, and an unmatched route falls through to a handler that answers 401 "missing subscription key" without a key and an empty-but-valid 200 with one. Measured 2026-09-18: /rest/data/STATSNZ,AGR_AGR_001,1.0/all?lastNObservations=1 → 200 with 80 observations; the same URL with %2C → 401. encodeURIComponent on that segment is what made statsnz_observations return count: 0 against a perfectly healthy dataset. /rest/dataflow/%61ll/all/latest → 401 too, so it is their routing, not this one path.

• A zero from statsnz_observations is always explained, and a bad id is an error. Because an unknown dataset, a malformed path and a genuinely empty query are indistinguishable by status on this gateway, the tool validates the dataset id against the keyless catalogue before calling the data endpoint (cached 30 min per isolate). An unknown id raises a 404-shaped error naming near matches; an id that exists but returns nothing comes back with empty_reason saying which case it is — no structure at all (routed but uninterpretable), a dimension key that filtered everything out, a period window with nothing in it, or a genuine upstream gap.

• An unfiltered query on a wide census table is too big to return, so the pack narrows it and says so. CEN23_HAD_020 with key all was ~208MB of SDMX-JSON on 2026-10-16 (no Content-Length, no time dimension for lastNObservations to shrink), past the pack's 16MB streaming cap; that was 24 of 44 external statsnz_observations calls in 48h. When the cap trips on an unfiltered query, the pack reads the dataset structure, pins geography dimensions (then the widest remaining ones, while the open cross product is over 250k cells) to the ROOT code Stats NZ labels "Total …" — never a "Total stated …" subtotal — re-queries, and returns the slice with requested_key: "all" and a narrowed object listing each pin and how to ask for the breakdown. CEN23_HAD_020 comes back as key .9999.... (Total - New Zealand by regional council), 16,920 rows. A caller-supplied key is never narrowed; a too-wide one, or a dataset with no Total code to pin, fails as user_error with the dimensions and sample codes inline.

• 401 does not mean "bad credential" here. Because an unmatched route also answers 401, a malformed path and a missing key are indistinguishable by status. The pack's 401 message says both possibilities out loud.

• Observations come back FLAT, not series-keyed. dataSets[0].observations is a map of "0:3" → [value, …] and dataSets[0].series is absent. Reading only series (as this pack first did) yields zero observations from a good

  200. Both layouts are mapped, plus dataset-level dimensions.

• lastNObservations drops the collapsed dimension from the observation key, and it is NOT always the time axis. With lastNObservations=1 on AGR_AGR_001 the key is 2 parts for 3 declared dimensions — the year is simply not in the response, so rows cannot say which year they are. On INC_INC_001 the collapsed dimension is MEASURE_INC_INC_001, a measure axis, across 35,610 rows. The pack reports collapsed_dimensions plus a note rather than returning rows that look fully labelled.

• startPeriod/endPeriod only bite on a declared time dimension, and Stats NZ mostly declares none. statsnz_resources reports time_dimension: [] for AGR_AGR_001, and the role field in the data message just echoes each dimension's own id, so there is no usable time marker: a dimension named YEAR_* is not a time dimension to this server. The pack therefore tests for the SDMX standard TIME_PERIOD id and, for anything else, tells the caller to pin the dimension through the key argument — naming its segment position and handing back a worked key such as ..<YEAR_AGR_AGR_001>. The note used to recommend startPeriod/endPeriod unconditionally, which is advice that cannot work on a measure axis (fleet #2244).

• Accept: application/vnd.sdmx.data+json;version=1.0.0 is a 406. Their server lists genericdata+xml 2.1 and data+json 2.0 as acceptable. Plain application/json returns SDMX-JSON 1.0 and is what this pack asks for.

• Wrong host looks like an outage. The older documented host api.stats.govt.nz answers HTTP 502 from its Azure Application Gateway on every path including the root. A 502 reads as "their service is down" when in fact the service moved. The live host is api.data.stats.govt.nz. Do not "fix" this pack back to the old hostname.

• A bare SDMX resource path 404s. /rest/dataflow is 404 Resource not found; only the fully-qualified /rest/dataflow/{agency}/{resource}/{version} form answers.

• Only 341 of the 911 dataflows carry a description; the rest are title-only, so keyword filtering leans on long formal titles ("Earnings for people in paid employment", never "wages").

• CPI, GDP and merchandise trade are NOT in this catalogue. Measured 2026-09-17: 0 of 911 dataflows mention "price", "consumer" or "trade"; 705 are census tables. Describing the pack as covering CPI would misroute every inflation question to a source that cannot answer it.

Quick Start

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

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

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/stats-nz/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 1857+ 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/statsnz_datasets \
  -H 'Content-Type: application/json' \
  -d '{"query":"household income","limit":5}'

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

Run it from npm

@pipeworx/mcp-stats-nz 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/stats-nz/mcp endpoint shown above. It needs network access; there is no offline mode.

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

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 Stats Nz data" })

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

More

• Docs and guides

• pipeworx.io

License

MIT