Gmail MCP

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is a retrieval operation ('Get'), implying read-only behavior, but doesn't specify authentication requirements, rate limits, error handling, or what happens if the thread ID doesn't exist. The description lacks crucial operational context for a tool that fetches data.

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 extremely concise - a single sentence that directly states the tool's purpose. There's no wasted language or unnecessary elaboration. It's front-loaded with the essential information and doesn't include any redundant content.

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?

For a read operation with no annotations and no output schema, the description is insufficient. It doesn't explain what data is returned, the format of the response, or any behavioral characteristics. While the purpose is clear, the description lacks the context needed for effective tool invocation in a complex email/thread management system with many sibling tools.

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?

Schema description coverage is 100%, so the schema fully documents both parameters (id and includeBodyHtml). The description doesn't add any parameter details beyond what's in the schema. According to scoring rules, when schema coverage is high (>80%), the baseline is 3 even without parameter information in the description.

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 action ('Get') and resource ('a specific thread by ID'), making the purpose immediately understandable. It distinguishes this from list_threads by specifying retrieval of a single thread rather than listing multiple. However, it doesn't explicitly contrast with get_message or other sibling tools beyond the thread focus.

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?

No guidance is provided on when to use this tool versus alternatives like get_message or list_threads. The description doesn't mention prerequisites, error conditions, or typical use cases. While the name implies thread-specific retrieval, there's no explicit comparison to sibling tools.

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