Arcnautical

com.arcnauticalPublished by arcnautical.comOfficial publisherv0.2.1Updated Oct 24, 2026

Screen any vessel by IMO for sanctions, ownership opacity and vetting grade. Keyless check included.

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Overview

AI-generated overview

ArcNautical screens commercial vessels by IMO number for sanctions matches, ownership opacity and a vetting grade, and scores route risk between ports.

What you can do
Screen a single vessel by IMO against sanctions lists, with ownership-opacity score and A–E vetting grade, without a key (rate-limited per IP). Retrieve the full screening record for one vessel, including every match, source list, programme and confidence class. Batch-screen up to 50 IMO numbers and wait for the results. Fetch a stored screening record by id from the ten-year audit retention. Resolve port names, countries or partial UN/LOCODEs to LOCODEs. Score voyage risk between two ports with drivers, confidence and missing sources. Check remaining allowance and limits for the configured key.
When to use it
Useful for compliance, shipping, trade-finance or logistics work where an assistant must check whether a hull is sanctioned, judge ownership opacity or vetting history, or assess route risk before a voyage. The keyless check is enough for quick one-off questions; the keyed tools are for full records, batches and voyage scoring.
Requirements
Either the remote endpoint (no install) or the local npm package run with npx, which needs Node 18+. No key is needed for check_vessel and find_port. The keyed tools need an API key, supplied as ARCNAUTICAL_API_KEY for the local server or as an Authorization Bearer header on the remote endpoint. Keys are self-serve and free. Network access to the ArcNautical API is required.
Before you install
The keyed tools are metered: each hull screened spends a screening unit unless already screened that day, and voyage assessments draw on a monthly allowance. The API key is a secret; keep it in the environment or header, not in shared configs. Verdicts are point-in-time and designations change daily, so quote the checked time. A keyless GREEN only matches the current name and identifiers, and INCOMPLETE or incomplete coverage must not be read as clear.

Installation

In SourceWeft

  1. Open Arcnautical in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.arcnautical%2Fmcp/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "arcnautical": {
      "type": "http",
      "url": "https://mcp.arcnautical.com/mcp"
    }
  }
}

README

@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.

[Smithery] [npm] [Wellknown: live]

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

Cursor — .cursor/mcp.json:

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:

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:

json
{  "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

ToolKey?What it does
check_vesselnoSanctions status (OFAC SDN, EU, UN, UK OFSI, OpenSanctions), ownership-opacity score, A–E vetting grade for one IMO. 100/hour per IP.
find_portnoResolve a port name or country to UN/LOCODEs — call before score_voyage.
screen_vesselyesThe 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_vesselsyesBatch up to 50 IMOs and wait for the results.
get_screeningyesRetrieve a stored record by id (retained ten years).
score_voyageyesRoute risk between two LOCODEs: score, level, drivers, confidence, missing sources.
get_usageyesRemaining 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

VariableDefaultPurpose
ARCNAUTICAL_API_KEYunsetEnables the keyed tools (stdio; the remote endpoint reads the Authorization header instead).
ARCNAUTICAL_BASE_URLhttps://arcnautical.comOverride for testing.
PORT / HOST3005 / all interfaces--http only.
MCP_TRUST_PROXYunset--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.

Links

Development

npm installnpm 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

MIT © ArcNautical

Source: README.md at commit eb254fc

Tools

7

check_vessel

Check a vessel (no key)

Screen one vessel by IMO number against OFAC SDN, EU, UN, UK OFSI and OpenSanctions, with an ownership-opacity score and an A–E vetting grade from port-state-control history. Works with no API key. Rate-limited to 100 requests per hour per IP. Returns the VERDICT SUMMARY only; for every sanctions match with its source list and confidence class use screen_vessel (needs a key).

Parametersimorequired

find_port

Find a port / UN/LOCODE (no key)

Resolve a port name, country or partial UN/LOCODE to the LOCODEs the routing engine knows. Routes are addressed by LOCODE, so call this before score_voyage rather than guessing a code. Works with no API key.

Parameterslimitqueryrequired

screen_vessel

Screen a vessel (full record, API key)

The authenticated screening record for one vessel: every sanctions match with its source list, programme and confidence class, ownership opacity, the graded vetting factors, per-source freshness, and a retained record id. Needs ARCNAUTICAL_API_KEY. Metered: a new self-serve key includes a one-time free allowance of live screenings; get_usage reports what is left. The same vessel asked again on the same day replays the stored record free. If the result is INCOMPLETE for identity, call again with vessel_name.

Parametersimorequiredvessel_nameinclude_vettingcustomer_reference

screen_vessels

Screen up to 50 vessels (API key)

Batch-screen a list of IMO numbers and wait for the results (up to two minutes). Returns one verdict per hull plus the batch status. Needs ARCNAUTICAL_API_KEY. Each hull spends one screening unit unless it was already screened today.

Parametersimosrequiredinclude_vetting

get_screening

Retrieve a screening record (API key)

Fetch a stored screening record by id — the audit copy, retained ten years. Needs ARCNAUTICAL_API_KEY.

Parametersidrequired

score_voyage

Score a voyage route (API key)

Route risk between two ports (UN/LOCODEs): a 0–100 score, risk level, the signals driving it (war-risk areas, piracy, chokepoints, weather, sanctions exposure of transited EEZs), confidence and any missing sources. Resolve port names with find_port first. Needs ARCNAUTICAL_API_KEY; 10,000 assessments a month are included with a self-serve key.

Parametersoriginrequireddwt_tonnesdestinationrequiredspeed_knotsvessel_typeload_conditioncustomer_reference

get_usage

Usage and quota (API key)

Live and test usage, remaining allowance, reset time, batch limits and monitor capacity for the configured key.

Takes no parameters.

Version history

2
  1. v0.2.1LatestSep 23, 2026
  2. v0.2.0Sep 18, 2026

Score

100% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

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Arcnautical

Published by GitHub account SaltyTaro

Screens commercial vessels by IMO number for sanctions, ownership opacity and vetting grade, with two keyless tools and keyed batch and voyage-risk tools.

STDIODesktop only
Location & LifestyleNot validated yetOct 27, 2026