mail_new

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals that the inbox is throwaway, external (mail.tm), and that a return address is provided for polling. This is meaningful behavioral context. It does not mention potential limitations like expiry or external service failures, but for a simple creation tool, the key behaviors are adequately disclosed.

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 well-structured sentence. It front-loads the primary action and includes the most important details without any filler or redundancy.

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?

This is a simple zero-parameter tool with an output schema. The description covers the purpose, the expected output, and how to use that output. It is complete for the tool's complexity and integrates well with the sibling tool mail_inbox.

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 tool has zero parameters, so no parameter documentation is needed. The description adds value by explaining what the tool returns (an address) and how to use that return value, which is more useful than an empty schema alone.

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 ('Create'), names the resource ('throwaway inbox'), specifies the provider (mail.tm), and states the intended use case (registering a test account). It clearly distinguishes this tool from siblings like mail_inbox by explaining what it produces and how the result is used.

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 clearly states when to use the tool: when registering a test account on an app you are authorized to test. It also explains how the returned address should be used (poll with mail_inbox), which provides usage context. It does not explicitly mention when not to use it or list alternatives, but none are needed given the unique purpose.

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