read_mail

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

The description adds a notable disclosure ('No passwords') and specifies the body format ('plaintext'), which provides some behavioral context. However, it does not mention return format, error behavior, or whether reading marks the message as read. With no annotations, the description carries the full burden, and it only partially addresses it.

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 two short sentences, front-loaded with the core action. Every word adds value, and there is no unnecessary elaboration or repetition. It is appropriately concise for a simple tool.

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 simplicity (one parameter, no output schema), the description still leaves important gaps: it does not explain the parameter semantics, usage context relative to siblings, or expected return. The minimal text is not enough for an agent to confidently invoke the tool correctly without additional assumptions.

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 schema has one required parameter 'id' with no description, and the tool description does not explicitly explain that 'id' is the mail message identifier. The phrase 'one mail message' implies the need to select a specific message, but the description does not clarify how the parameter is used or formatted. Schema description coverage is 0%, so the description should compensate, but it does not.

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 uses a specific verb ('Read') and resource ('one mail message') and specifies scope ('one') and content ('including plaintext body'). It clearly distinguishes from siblings like search_mail, which implies a broader search/listing operation.

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 explicit guidance is given about when to use this tool versus alternatives. There is no mention of exclusions or prerequisites. The usage is only implied by the verb 'Read', but no context is provided for selection among mail-related siblings.

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