Gmail MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behaviors: it opens a browser window, starts a local server, handles callbacks, and returns a message. This covers the interactive and server aspects well, though it could mention potential user interaction requirements or error handling.

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

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

The description is front-loaded with the main purpose, followed by implementation details and return value in three clear sentences. Each sentence adds value: the first states the action, the second explains the mechanism, and the third specifies the output. There is no wasted text.

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

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

Given the tool's complexity (OAuth flow with browser/server interaction), no annotations, and no output schema, the description is mostly complete. It explains what the tool does, how it works, and the return type. However, it could improve by detailing prerequisites (e.g., requires user interaction) or error cases, slightly reducing completeness.

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

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

The input schema has 0 parameters with 100% coverage, so no parameter documentation is needed. The description appropriately focuses on the tool's action and return value without redundant parameter details, earning a baseline score of 4 for this context.

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

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

The description clearly states the tool's purpose with specific verbs ('Start', 'opens', 'starts') and resources ('OAuth authentication process', 'browser window', 'local server', 'callback'). It distinguishes itself from sibling tools like 'login_tool' or 'process_auth_code_tool' by describing the complete OAuth flow initiation rather than just checking status or processing codes.

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

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

The description implies usage context by stating it 'starts the complete OAuth authentication process,' suggesting this should be used when initial authentication is needed. However, it doesn't explicitly state when NOT to use it or name specific alternatives among the sibling tools, such as 'check_auth_status' for verification or 'process_auth_code_tool' for handling codes.

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