mail_get

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

Annotations already declare readOnlyHint=true, so safety is clear. Description adds valuable behavioral detail: unwraps forwarded messages to extract original. This goes beyond annotations. No contradiction.

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?

Concise two-paragraph structure. First sentence states core purpose. Second paragraph lists return keys clearly. No redundant information.

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 that an output schema exists (context signal), the description adequately explains the return values. However, it does not mention error handling (e.g., if ID not found). For a simple read tool, this is good but not perfect.

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 has 0% description coverage, yet the description does not explain what message_id is (e.g., 'Gmail message ID'). While it may be obvious, the description fails to add meaning beyond the parameter name. Baseline 3 is reduced because the schema lacks descriptions and the tool description does not compensate.

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?

Clearly states it fetches a single email by ID. Distinguishes from sibling tools like mail_search (which searches) and mail_list_pending (which lists pending). The verb 'Fetch' and resource 'email' are specific.

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?

Implied usage: when you have an email ID and want full details. But no explicit guidance on when not to use it or alternatives. For example, could mention that mail_search is for finding emails by query.

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