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Watch & Navy MCP server

Which servers in the official MCP registry are Watch & Navy's own, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-17

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Whose server it is
  • Registry namecom.watchandnavy/mariner-gps-toolsverified in the MCP registry

The registry name sits under watchandnavy.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-17
  • Stateanswerschecked 2026-10-17
  • Tools6
  • Server calls itselfmariner-tools
  • Server version1.0.1
  • Protocol version2025-06-18

On 2026-10-17 the server answered initialize and tools/list without a sign-in. First answer in 494 ms.

Should an agent connect itSkip it
  • Its tools do none of the product's use cases we checked: log road journeys with speed and route tracking; log boat voyages and automate the logbook.
  • Checked on 4 of the 7 days it takes to judge reliability.

Once connected

  • Parameters are untyped or undescribed in 2 of 6 tools: check arguments before calling.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 4, the first on 2026-10-19
  • INITE MCP scoreafter a weeka score needs 7 daily checks: 4 so far
  • What an agent can do with it0 of 2 use cases
  • Answeredmeasuring4 of the 7 daily checks it takes to print a share
  • Median first answer512 ms
  • Space in an agent's context≈ 1,691 tokensthe definitions of all its tools (6), which an agent carries on every turn
  • Tool definitionsB · 78 of 100
  • Typed results6 of 6 toolsdeclared outputSchema: results come typed, read once
  • Parameters without a description: in 2 of 6
  • Not saying whether it only reads or can destroy: 6 of 6

What an agent can do with it

  • cannot · log road journeys with speed and route tracking
  • cannot · log boat voyages and automate the logbook
  • not sure · measure distances and estimate travel times for routes

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

None of the five warning signs in these definitions.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (30%), doing the product's job (25%), definitions (20%), context (10%) and use (15%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers6 tools · read 2026-10-17
  • convert_speed

    Convert a speed value between knots, mph, km/h, m/s, and ft/s.

  • convert_coordinates

    Parse latitude and longitude and format them as decimal degrees or DMS.

  • calculate_distance

    Calculate great-circle and rhumb-line routes between two GPS coordinates.

  • calculate_bearing

    Calculate the initial true bearing between two GPS coordinates.

  • calculate_cross_track_error

    Calculate cross track error (XTE) — the perpendicular distance from a vessel position to the great-circle track between two waypoints — plus side of track (port/starboard) and along-track distances.

  • list_tools

    List the public Mariner GPS Tools calculators currently available.

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "mariner-gps-tools": {
      "type": "http",
      "url": "https://marinergps.tools/mcp"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http watchandnavy https://marinergps.tools/mcp

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://marinergps.tools/mcp as a custom connector in the settings.

Other servers listed as Watch & Navy's
  • com.watchandnavy/road-user-toolsanswers, 9 toolsverified in the MCP registry

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.