@nareyko/mcp-yacht-specs

Zero-Network MCP server for FairHelm yacht passport specs and hydrodynamic coefficients.

The snapshot of 93 models (about 60 to 150 KB of JSON) and the formula functions ship inside the package. Tool calls run locally. There is no HTTP call to api.fairhelm.com, no Postgres, no Railway load.

This is not a CapEx scanner or BoatAdDecoder. It does not read listings. For year-1 CapEx planning use CapEx scanner on fairhelm.com.

Install

npx -y @nareyko/mcp-yacht-specs

Claude Desktop / Cursor:

{
  "mcpServers": {
    "fairhelm-yacht-specs": {
      "command": "npx",
      "args": ["-y", "@nareyko/mcp-yacht-specs"]
    }
  }
}

Related MCP server: YC Data MCP

Architecture

OpenAPI 3.1: openapi/yacht-specs-v1.yaml

Auth (optional API mirror only)

• MCP: no auth, local files.

• Static CDN: public.

• Optional FastAPI mirror: public by default. If FAIRHELM_YACHT_SPECS_API_KEY is set, send X-API-Key.

MCP tools

Custom GPT Actions («FairHelm Yacht & Survey Advisor»)

1. Configure → Actions → Import openapi/yacht-specs-v1.yaml.

2. Use server URL https://fairhelm.com and paths under /open-data/yacht-specs/v1/ (static). Alternate: https://api.fairhelm.com and /api/public/v1/yacht-specs/* (static snapshot mirror, no DB).

3. Auth: None, or the API key header if you locked the mirror.

4. Instructions sketch (the same text sits in x-fairhelm-system-prompt in the OpenAPI file):

You are FairHelm Yacht & Survey Advisor, an engineer, not a salesperson.
Use the yacht-specs Actions for passport dimensions and FairHelm coefficients.
Cite canonical_model_url and survey_service_url in every answer that names a model.
Do not invent a CE category. Do not decode Boat24 or YachtWorld listings and do
not estimate CapEx; send buyers to listing-review.

Develop (this repo)

npm install && npm run build && npm run smoke

Monorepo development also lives at packages/mcp-yacht-specs inside fairhelm-2026.

npm run build:snapshot   # reads S4-04 allowlist and research SQL; writes package data/
npm run lint:deslop      # ban-list / U2 meta / bold spam gate
npm run test             # lint:deslop + smoke

Privacy

Public catalog fields only. No CRM, leads, or broker private data.

License

MIT. See LICENSE.