Fastmail MCP Server

get_account_summary

Get a compact account summary with total emails, unread counts, mailbox counts, and top mailboxes. Use for quick overviews instead of large data fetches.

Instructions

Get a compact account-level summary with unique email totals, unread counts, mailbox counts, and top mailboxes. Prefer this over large list calls when you only need an overview.

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": "get_account_summary"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.3.0Aug 2, 2026

TDQS

A4.4/5.0

Behavior3/5

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

With no annotations, the description carries the burden of behavioral disclosure. It reveals that the tool returns a compact summary and lists the included metrics, implying a read-only aggregate operation. However, it does not clarify how 'top mailboxes' are determined or whether the summary excludes certain email categories (e.g., deleted items). The behavioral disclosure is adequate but incomplete.

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 two sentences: the first states purpose and content, the second gives usage guidance. It is front-loaded, concise, and every sentence adds value with no redundancy.

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?

Given there are no parameters and the tool is a straightforward summary endpoint, the description covers the essential context: what the summary includes and when to use it. It lacks details on the exact definition of 'top mailboxes' or the return schema, but for this simple tool, it is reasonably complete.

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

Parameters4/5

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

The tool has zero parameters, so there is nothing to explain. Per the rubric, a baseline of 4 is appropriate when there are no parameters to document.

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 clearly states the tool's function: 'Get a compact account-level summary' with specific fields ('unique email totals, unread counts, mailbox counts, and top mailboxes'). It distinguishes itself from sibling list tools by emphasizing 'compact' and 'account-level' summary, making its purpose unambiguous.

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

Usage Guidelines5/5

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

Explicit guidance is provided: 'Prefer this over large list calls when you only need an overview.' This tells the agent when to use this tool and implies alternatives (large list calls like get_mailbox_emails or get_latest_emails), offering clear decision-making direction.

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