Gmail MCP Server

gmail_list_messages

List Gmail messages using a search query to filter results. Control the number of messages returned, up to 100.

Instructions

List Gmail messages with optional search query.

Args: query: Gmail search query (e.g., 'from:sender@example.com', 'is:unread') max_results: Maximum number of messages to return (1-100)

Returns: Dictionary with success status and message data

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": "gmail_list_messages"
  }
}

Input Schema

Name	Required	Description	Default
`query`	No
`max_results`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 30, 2026

TDQS

B3.1/5.0

Behavior2/5

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It states the return format but does not disclose that the operation is read-only, idempotent, or safe. It lacks details on side effects, rate limits, or resource consumption. For a list operation, basic safety traits are expected.

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 extremely concise: one sentence explaining purpose, followed by a compact parameter list and return format. Every element is necessary and contributes meaning. There is no redundant or filler content.

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

Completeness2/5

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

Despite low complexity (2 parameters, no output schema), the description is incomplete. It does not explain default behavior (e.g., what messages are returned when no query is given), pagination, ordering, or limitations. The mention of 'message data' in returns is vague, and the sibling tools suggest potential overlap that is not disambiguated.

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 input schema has no property descriptions (0% coverage), so the description adds significant value by providing concrete examples for the 'query' parameter (e.g., 'from:sender@example.com') and specifying the valid range for 'max_results' (1-100). This helps the agent form correct queries.

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?

The description clearly states the tool lists Gmail messages and allows an optional search query. However, it does not differentiate from the sibling 'gmail_search_messages' tool, which may have similar functionality. The verb 'List' and resource 'Gmail messages' are specific.

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

Usage Guidelines2/5

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

The description provides no guidance on when to use this tool versus alternatives like 'gmail_search_messages'. It does not specify prerequisites (e.g., authentication, mailbox) or exclusions. The agent is left to infer usage from the tool name alone.

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

Deploy Server