Reference Data MCP Server

by cyanheads Your server? Claim it

answering

Reference Data MCP Server is answering right now. Last checked 15 min ago. 755 installs a week from npm. It exposes 10 tools. Last commit 28 Oct 2026.

Countries, timezones, elements, constants, HTTP status codes, unit conversion, and MIME type lookup.

Installs per day peak 312 · avg 49 · +297% w/w

a month agotoday

Uptime history 43 days of history · worst day 94%

43 days agonow

100.0%

Uptime 24h

91 of 91 checks

Tools

read from the server

572 ms

Response time

average over 24h

755

Installs / week

npm and PyPI

What changed 3

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 9 October 2026. No other catalogue keeps this.

28 Oct a tool changed version

25 Oct a tool changed version

9 Oct a tool changed version

Nothing serious here today

Today is the operative word: we check Reference Data MCP Server every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 15 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add reference-data-mcp-server --transport http https://reference-data.caseyjhand.com/mcp

Settings → Connectors → Add custom connector, then paste this address

https://reference-data.caseyjhand.com/mcp

~/.codex/config.toml

[mcp_servers.reference-data-mcp-server]
url = "https://reference-data.caseyjhand.com/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "reference-data-mcp-server": {
      "url": "https://reference-data.caseyjhand.com/mcp"
    }
  }
}

.vscode/mcp.json

{
  "servers": {
    "reference-data-mcp-server": {
      "type": "http",
      "url": "https://reference-data.caseyjhand.com/mcp"
    }
  }
}

Available tools 10

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

ref

ref_constant_lookup

Look up a fundamental physical constant by name, symbol, or common alias. Returns the CODATA 2022 value, SI unit expression, relative standard uncertainty, and a short description. Recognizes common names and symbols — "speed of light", "c", "Avogadro's number", "N_A", "Planck", "h", "Boltzmann", "k_B" all resolve correctly. Fuzzy matching returns the closest match plus alternatives.

ref_element_lookup

Look up a periodic table element by name, chemical symbol, or atomic number. Returns the full data record: atomic number, symbol, name, atomic mass (in unified atomic mass units), electron configuration, group, period, block, category (e.g., "noble gas", "transition metal"), Pauling electronegativity, density (g/cm³), melting and boiling points in kelvin, and discovery year. Properties unavailable for synthetic or insufficiently studied elements are returned as null.

ref_element_search

Filter periodic table elements by category, group, period, atomic number range, or atomic mass range. At least one filter is required. Returns matching elements as a summary list. Use ref_element_lookup for the full record on a specific element. Valid categories: alkali metal, alkaline earth metal, transition metal, post-transition metal, metalloid, reactive nonmetal, noble gas, lanthanide, actinide.

ref_geo_lookup

Look up a country by name, ISO alpha-2 code (2 letters), or ISO alpha-3 code (3 letters). Returns the full record: capital, region, official languages, currencies, calling codes, TLD, flag emoji, and IANA timezone IDs. Accepts fuzzy name matching — "Brasil" and "Brazil" both resolve.

ref_geo_search

Search and filter countries by region, subregion, language, currency, or free-text keyword. At least one filter is required. Returns a ranked list of matching country summaries. Use ref_geo_lookup to get the full record for a specific result.

ref_http_status

Look up an HTTP status code by number or keyword. Returns the reason phrase, description, category (1xx Informational, 2xx Success, 3xx Redirection, 4xx Client Error, 5xx Server Error), whether the code is cacheable by default, and the defining RFC with section reference. For keyword queries, returns the closest match plus alternatives.

ref_mime_type

Look up a MIME type by type string or file extension. Accepts "image/webp", ".webp", or "webp". Returns the canonical MIME type, known file extensions, whether the type is compressible (relevant for Content-Encoding decisions), and the data source (iana, apache, nginx). For extension lookups, returns the canonical MIME type — e.g., ".jpg" resolves to "image/jpeg". When multiple types map to an extension, the canonical type is returned first with alternatives listed.

ref_timezone_convert

Convert a local datetime from one timezone to another. Takes a local time string (no UTC offset, e.g., "2026-05-24T15:30:00") interpreted as local time in the source timezone, returns the equivalent local time in the target timezone. Shows both UTC offsets so DST transitions are visible. Accepts full IANA IDs (e.g., "Asia/Tokyo") or unambiguous city names (e.g., "Tokyo").

ref_timezone_lookup

Get timezone info by IANA ID, country code, or partial city/region name. Returns current UTC offset, standard offset, whether DST is currently active, and major cities in the timezone. When querying by country code (ISO alpha-2), returns all timezones observed in that country. Accepts partial matches — "Tokyo" resolves to "Asia/Tokyo", "NY" resolves to "America/New_York".

ref_unit_convert

Convert a numeric value between compatible units of measure. Supports: length (mm, cm, m, km, in, ft, yd, mi), mass (mcg, mg, g, kg, oz, lb, mt = metric tonne / 1000 kg, t = US short ton / 907.18 kg), volume (ml, cl, dl, l, kl, tsp, Tbs, fl-oz, cup, pnt, qt, gal, m3), temperature (C, F, K, R — non-linear conversions handled), speed (m/s, km/h, knot, ft/s), pressure (Pa, kPa, MPa, hPa, bar, torr, psi), energy (J, kJ, Wh, kWh, MWh), power (W, mW, kW, MW, GW), frequency (Hz, kHz, MHz, GHz), digital storage (b, Kb, Mb, Gb, Tb, B, KB, MB, GB, TB), and angle (deg, rad, grad). Incompatible units (e.g., km to kg) return an error identifying the quantity mismatch.

Endpoints

URL	Transport	State	Latency	Checked
https://reference-data.caseyjhand.com/mcp	streamable-http	answering	542 ms	15 min ago

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Reference Data MCP Server — questions

Answers built from our own checks of this server.

What can Reference Data MCP Server do?

It exposes 10 tools, read directly from the server on our last check. Among them: ref_constant_lookup, ref_element_lookup, ref_element_search, ref_geo_lookup, ref_geo_search, ref_http_status and 4 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is Reference Data MCP Server working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 91 of 91 checks got a reply (100.0%), average response time 572 ms. The bar chart above shows every period we have measured.

How do I connect Reference Data MCP Server?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does Reference Data MCP Server need an API key?

No. Reference Data MCP Server completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 10 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is Reference Data MCP Server?

It answers our handshake in 572 ms on average, which is faster than 20% of all working MCP servers we measure. That is on the slow side — worth knowing if the tool sits inside an interactive loop. The comparison comes from our own checks across the whole registry, every 15 minutes.

How many people use Reference Data MCP Server?

The npm package @cyanheads/reference-data-mcp-server was installed 755 times in the last week. Week over week that is +297%. We show installs rather than GitHub stars on purpose: a star is a bookmark, an install is someone actually running it.

Is Reference Data MCP Server open source?

The code is open source: it is published under the Apache-2.0 licence, written in TypeScript, 1 stars on GitHub and 3 open issues. The licence covers the code in the repository, not the hosted service at reference-data.caseyjhand.com, which runs on its operator's own terms.