mail_get

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

Annotations indicate read-only and non-destructive. Description adds valuable behavioral details: unwraps forwarded messages, lists exact return keys including attachment_paths. No contradictions.

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?

Very concise: two sentences and a bullet list of return keys. No redundant words, front-loaded with action.

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?

Even with an output schema, the description provides complete details about return values, including special unwrapping behavior and attachment paths. One parameter is fully handled.

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 one parameter 'message_id' with 0% coverage. Description clarifies it's an ID but does not explain format or validation. However, the parameter name is self-explanatory, so the agent can infer it's the email identifier.

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 'Fetch a single email by ID' and distinguishes from sibling tools like mail_search and mail_list_pending by specifying it retrieves a single email. Also mentions unwrapping forwarded messages, adding further specificity.

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?

Explicitly says to use for fetching a single email by ID. Implicitly excludes batch operations, but does not provide explicit when-not or alternatives. Context from sibling names helps, but description could be more directive.

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