VesselAPI MCP Server

by vessel-api

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TypeScript

search_ports

Find ports by name, country, region, type, size, harbor size, or use to retrieve matching maritime port records.

Instructions

Search for ports by name, country, type, size, region, harbor size, or harbor use

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "search_ports"
  }
}

Input Schema

Name	Required	Description
`name`	No	Port name (partial match)
`size`	No	Port size classification
`limit`	No	Results per page, 1 to 50. Defaults to 20.
`region`	No	Geographic region (partial match)
`country`	No	Country (ISO code)
`portType`	No	Port type classification
`harborUse`	No	Primary harbor use
`nextToken`	No	Pagination token from previous response
`harborSize`	No	Harbor size classification

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv2.2.0Oct 30, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```
Changed4 schema fields changedv2.0.0Aug 20, 2026
- changedInput schema / properties / limit / description
```
Previous value: -"Max results per page"New value: +"Results per page, 1 to 50. Defaults to 20."
```
- addedInput schema / properties / limit / maximum
```
Added value: +50
```
- addedInput schema / properties / limit / minimum
```
Added value: +1
```
- changedInput schema / properties / limit / type
```
Previous value: -"number"New value: +"integer"
```
Addedv1.3.0May 6, 2026

TDQS

B3.2/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full behavioral burden. It says nothing about whether this is read-only, what the response contains, or how pagination behaves, despite pagination params existing in the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single efficient sentence that front-loads the action and the facets. No filler, though it could be slightly more directive about filtering behavior.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no annotations or output schema, the description should clarify return shape and pagination, which it omits. The rich parameter schema compensates for filter semantics, but behavioral completeness is only minimal.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so each parameter is already documented, including partial-match notes and the ISO code for country. The description merely echoes the filter field names and adds no syntax or format meaning beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (search) and resource (ports) plus the filterable facets, which distinguishes it from get_port (single retrieval). It does not explicitly name or contrast with siblings like get_port, but the search semantics are clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The list of filter dimensions implies 'use this to find ports by attributes,' but there is no explicit when-to-use vs when to prefer get_port or search_port_events_by_port, and no prerequisites or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.