reference-data-mcp-server

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

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What it can do

  • 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,
  • 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 re
  • 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 time

What data it sees

Do you need an account

No: the server works without sign-in

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

How to connect

How to connect reference-data-mcp-server to Claude

The server address to paste into Claude settings:

https://reference-data-mcp-server--cyanheads.run.tools

  1. Open Claude (claude.ai or the desktop app).
  2. Go to Settings → Connectors.
  3. Click Add custom connector.
  4. Paste the server address copied below into Remote MCP server URL and click Add.
  5. In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect reference-data-mcp-server to ChatGPT

The server address to paste into ChatGPT settings:

https://reference-data-mcp-server--cyanheads.run.tools

  1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
  2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
  3. Open Settings → Connectors and click Create.
  4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
  5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
  6. In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect reference-data-mcp-server to Cursor

The server address to paste into Cursor settings:

https://reference-data-mcp-server--cyanheads.run.tools

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

  1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
  2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
  3. Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (10)

Raw names from tools/list. Only developers need these.

ref_geo_lookupLook 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_searchSearch 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_timezone_lookupGet 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_timezone_convertConvert 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_element_lookupLook 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_searchFilter 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_constant_lookupLook 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_unit_convertConvert 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, t), 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.
ref_http_statusLook 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_typeLook 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.