mail_inbox

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

With no annotations, the description carries the full burden. It discloses that the tool returns messages and links and that the inbox is a throwaway, which implies non-persistent and read-oriented behavior. However, it doesn't explicitly state whether polling is destructive, whether any authentication is needed, or what happens if the inbox doesn't exist.

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 a single, front-loaded sentence that conveys purpose, usage context, and output in a compact form. Every word adds value, with no filler.

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 simple one-parameter tool with an output schema, the description is nearly complete. It explains the tool's role, ties it to mail_new, and notes the returned links. It falls slightly short only by not explicitly linking the 'address' parameter to the inbox, but otherwise the context is sufficient.

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 'address' with no description, and schema description coverage is 0%. The description doesn't explicitly define 'address' as the inbox email address, though it can be inferred from 'throwaway inbox created by mail_new()'. Since coverage is 0%, the description should compensate more clearly.

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 verb 'Poll' and the resource 'a throwaway inbox created by mail_new()', distinguishing it from sibling tools like mail_new which creates the inbox. It also specifies the output: messages and links (e.g., verification link).

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 a clear usage context: poll an inbox that was created by mail_new(), likely after signup to retrieve a verification link. It doesn't explicitly exclude alternatives or state when not to use it, but the sibling context and 'created by mail_new()' provide solid guidance.

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