Look up HTTP status codes, MIME types, periodic table elements, and convert units via @cyanheads/reference-data-mcp-server (npx)

Recipe: Reference data lookups via @cyanheads/reference-data-mcp-server

Package: @cyanheads/[email protected] (npm) Transport: stdio (set MCP_TRANSPORT_TYPE=stdio) Auth: None required — all data is bundled in-memory Launch: MCP_TRANSPORT_TYPE=stdio npx -y @cyanheads/[email protected]

10 tools available

Verified execution trace

All 4 calls below ran on 2026-06-12 against v0.1.10 (server reports as v0.10.6 internally).

1. HTTP status code lookup — 418

→ {"method":"tools/call","params":{"name":"ref_http_status","arguments":{"query":"418"}}}
← code: 418, reason_phrase: "I'm a Teapot", category: "4xx Client Error", rfc: "RFC 2324 §2.3.2"

2. Periodic table element — Gold

→ {"method":"tools/call","params":{"name":"ref_element_lookup","arguments":{"query":"gold"}}}
← symbol: Au, number: 79, atomic_mass: 196.97, category: "transition metal", density: 19.3 g/cm³, melting_point: 1337.33 K

3. MIME type lookup — .json

→ {"method":"tools/call","params":{"name":"ref_mime_type","arguments":{"query":".json"}}}
← type: "application/json", extensions: ["json","map"], compressible: true, source: "iana"

4. Unit conversion — 100 km → miles

→ {"method":"tools/call","params":{"name":"ref_unit_convert","arguments":{"value":100,"from":"km","to":"mi"}}}
← result: 62.1371 mi, measure: "length"

Notes

• Requires MCP_TRANSPORT_TYPE=stdio env var (defaults to HTTP otherwise)
• Package warns about Node ≥24 requirement but works on Node 22
• All responses include both human-readable content[].text and machine-readable structuredContent
• Pure in-memory — no network calls, sub-millisecond response times
• Rich data: HTTP status includes RFC references, elements include electron configuration and discovery info