How do I install Arcnautical?

Copy the http config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does Arcnautical need an API key?

The publisher lists these environment variables: ARCNAUTICAL_API_KEY.

What transport does Arcnautical use?

Arcnautical is reached over HTTP.

When was Arcnautical last checked?

Last checked 2026-10-22. Screen any vessel by IMO for sanctions, ownership opacity and vetting grade. Keyless check included.

Arcnautical MCP server

Power your agent

Add this server

The publisher's own URL. Not a PlugMCP endpoint.

Add to Cursor Add in Claude Add to VS Code Run on PlugMCP

Host a copy with our keys and logs.

Server URL

https://mcp.arcnautical.com/mcp

Credentials from the publisher

ARCNAUTICAL_API_KEY — Optional. Self-serve at https://arcnautical.com/get-a-key?from=mcp; unlocks the full screening record, batches and voyage scoring. check_vessel and find_port work without it.

The Claude button above opens Claude with the name and URL filled in. You still confirm it there.

shClaude Code

1claude mcp add --transport http com.arcnautical-mcp https://mcp.arcnautical.com/mcp

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "com.arcnautical-mcp": {4      "command": "npx",5      "args": [6        "-y",7        "mcp-remote",8        "https://mcp.arcnautical.com/mcp"9      ]10    }11  }12}

claude_desktop_config.json

Remote · HTTPPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Run on PlugMCP

Host a copy with our keys and logs.

A new server you create. It is not this listing's official endpoint. Use the publisher install when you want their URL and their credentials.

Launch

Server facts

Remote

Transport: http
Version: 0.2.1

7 tools

Tools

tools/listVoice mode preview

Tool	What it does

@arcnautical/mcp

An MCP server for the ArcNautical API: screen any commercial vessel by IMO number for sanctions, ownership opacity and a vetting grade — from Claude, ChatGPT, Cursor, VS Code, Windsurf or any MCP client.

Two tools need no API key at all. Add it, ask "is IMO 9274446 sanctioned?", get the answer.

Two ways to use it: a remote endpoint at https://mcp.arcnautical.com/mcp (nothing to install — claude.ai, ChatGPT, Claude Code, Cursor) or a local server over stdio with npx -y @arcnautical/mcp (Claude Desktop and every other stdio client).

IMO 9274446 HS STAR: sanctions RED — 4 confirmed matches on vessel identifier.
Ownership opacity MEDIUM. Vetting grade E (unacceptable). Checked 2026-09-12T08:10:40Z.

Remote endpoint (no install)

https://mcp.arcnautical.com/mcp — MCP Streamable HTTP, stateless, JSON responses. No authentication is required for check_vessel and find_port; the keyed tools take your API key as an Authorization: Bearer header on the MCP request (an X-API-Key or arcnautical-api-key header is accepted too, for gateways that name the header themselves — never a query parameter).

claude.ai — Settings → Connectors → Add custom connector → URL https://mcp.arcnautical.com/mcp, no authentication. The two keyless tools are available at once.

ChatGPT — Settings → Connectors → Create (developer mode) → server URL https://mcp.arcnautical.com/mcp, no authentication.

Claude Code

claude mcp add --transport http arcnautical https://mcp.arcnautical.com/mcp
claude mcp add --transport http arcnautical https://mcp.arcnautical.com/mcp --header "Authorization: Bearer arc_live_…"

Cursor — .cursor/mcp.json:

{
  "mcpServers": {
    "arcnautical": {
      "url": "https://mcp.arcnautical.com/mcp",
      "headers": { "Authorization": "Bearer arc_live_…" }
    }
  }
}

Anything with curl — the endpoint is plain JSON-RPC over POST:

curl -s https://mcp.arcnautical.com/mcp -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"check_vessel","arguments":{"imo":"9274446"}}}'

The remote endpoint is a thin client of the same public API: a keyless call counts against your 100-per-hour allowance (the caller's address is forwarded), and a keyed call is metered on your key exactly as a direct API call would be. GET /mcp answers 405 — there is no server-to-client stream to hold — and GET https://mcp.arcnautical.com/health reports the endpoint's version.

Local server (stdio)

Requires Node 18+. No install step — every client below runs it with npx.

Claude Desktop — claude_desktop_config.json:

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

Claude Code

claude mcp add arcnautical -- npx -y @arcnautical/mcp

Cursor / Windsurf / VS Code — same command / args shape in the client's MCP settings.

To unlock the full record, batches and voyage scoring, add an API key to the env block:

{
  "mcpServers": {
    "arcnautical": {
      "command": "npx",
      "args": ["-y", "@arcnautical/mcp"],
      "env": { "ARCNAUTICAL_API_KEY": "arc_live_…" }
    }
  }
}

Keys are free and self-serve at https://arcnautical.com/get-a-key?from=mcp — no card, no approval step. A new key includes a one-time free allowance of vessel screenings and a monthly allowance of voyage assessments; get_usage reports both, and the current numbers are on arcnautical.com/developers.

Tools

Tool	Key?	What it does
`check_vessel`	no	Sanctions status (OFAC SDN, EU, UN, UK OFSI, OpenSanctions), ownership-opacity score, A–E vetting grade for one IMO. 100/hour per IP.
`find_port`	no	Resolve a port name or country to UN/LOCODEs — call before `score_voyage`.
`screen_vessel`	yes	The full screening record: every match with its source list, programme and confidence class, the graded vetting factors, per-source freshness, a retained record id. Same hull asked again today replays free.
`screen_vessels`	yes	Batch up to 50 IMOs and wait for the results.
`get_screening`	yes	Retrieve a stored record by id (retained ten years).
`score_voyage`	yes	Route risk between two LOCODEs: score, level, drivers, confidence, missing sources.
`get_usage`	yes	Remaining allowance and limits for the configured key.

Reading a verdict

RED — confirmed match on the vessel identifier. AMBER — possible match, review it. GREEN — no match against the sources reached. INCOMPLETE — a core source could not be read; never present it as clear.
coverage_complete: false on a GREEN means one supplementary list was unavailable: re-screen before relying on it.
assessed: false means ownership and vetting are defaults, not findings.
The keyless check matches the vessel's current name and identifiers only. A hull renamed after a designation can read GREEN there; screen_vessel covers that case.
Designations change daily. Quote the checkedAt / screened_at time with any answer.

Idempotency

Every resource-creating call sends an Idempotency-Key derived from the question — the hull and the UTC day — not from the attempt. Asking about the same vessel twice in a day returns the stored record and spends nothing. The API's docs measured 42% of one integration's monthly screenings as same-day repeats billed only because their client generated a random key per call; this server does not do that.

Environment

Variable	Default	Purpose
`ARCNAUTICAL_API_KEY`	unset	Enables the keyed tools (stdio; the remote endpoint reads the `Authorization` header instead).
`ARCNAUTICAL_BASE_URL`	`https://arcnautical.com`	Override for testing.
`PORT` / `HOST`	`3005` / all interfaces	`--http` only.
`MCP_TRUST_PROXY`	unset	`--http` only: `1` reads the caller's address from `X-Real-IP` / `CF-Connecting-IP` set by a reverse proxy. Only when nothing but the proxy can reach the port.

Self-hosting the HTTP endpoint

npx -y @arcnautical/mcp --http serves POST /mcp on port 3005 — useful when your assistants run in a network that cannot spawn local processes but can reach one internal URL. The Dockerfile in this repository builds the same thing; it is what mcp.arcnautical.com runs.

Development

npm install
npm test        # builds, then drives dist/cli.js over stdio AND createHttpServer() over Streamable HTTP
                # (a local stub API asserts the forwarded caller address and Bearer key; one call hits prod keyless)
npm run start:http   # the remote endpoint on http://localhost:3005/mcp

Arcnautical

Add this server

Host a copy with our keys and logs.

Server facts

Tools

Questions

How do I install Arcnautical?

Does Arcnautical need an API key?

What transport does Arcnautical use?

When was Arcnautical last checked?

Documentation

@arcnautical/mcp

Remote endpoint (no install)

Local server (stdio)

Tools

Reading a verdict

Idempotency

Environment

Self-hosting the HTTP endpoint

Links

Development