Fastmail MCP Server

get_contact

Retrieve complete details for a specific contact in Fastmail by providing its contact ID. Use this to access full contact information when you know the ID.

Instructions

Get full details of a specific contact by their ID

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "contactId": "<contactId>"
    },
    "name": "get_contact"
  }
}

Input Schema

Name	Required	Description	Default
`contactId`	Yes	The contact ID to retrieve

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.3.0Aug 2, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations provided, the description carries the behavioral transparency burden. The verb 'Get' clearly indicates a read operation, and 'full details' hints at the comprehensive nature of the response. However, it does not disclose potential errors, permissions, or the exact return structure, leaving some ambiguity for an agent.

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

Conciseness5/5

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

The description is a single sentence, front-loaded with the action and resource, and contains no redundant words. It efficiently communicates the purpose without wasting tokens.

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

Completeness4/5

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

For a simple 1-parameter, no-output-schema tool, the description is largely sufficient. It names the resource, the action, and the required ID. However, it lacks any usage guidance or mention of sibling alternatives, which would make it more complete in the broader tool context.

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?

The input schema fully describes the single parameter contactId with the description 'The contact ID to retrieve', achieving 100% schema coverage. The description adds no new semantic detail beyond 'by their ID', so the baseline score of 3 applies as the schema carries the explanatory weight.

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

Purpose5/5

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

The description 'Get full details of a specific contact by their ID' clearly states the verb (Get), the resource (contact), and the scope (by ID). It distinguishes itself from sibling tools like search_contacts (searching) and get_identities (different resource), making it unambiguous which action it performs.

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 description implies usage when you have a contact ID and need full details, but it does not explicitly mention when not to use it or point to alternatives like search_contacts. The context is clear but lacks explicit guidance on choosing this over similar tools.

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