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

Annotations already indicate a mutating, open-world operation, and the description adds meaningful context beyond them: the URL is public, anyone can POST to it, deliveries become await-able events, and there is a per-call cost. This is useful behavioral disclosure without contradicting the annotations.

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?

Every sentence earns its place: a clear opening statement of what the tool does, a practical usage condition, and a pricing note. The description is short and front-loaded, with no redundant phrasing.

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 two-parameter tool with no output schema, the description conveys the core behavior, the return concept (a public URL), the use case, and cost. It could add retention or deletion behavior, but the essentials an agent needs to call it correctly are present.

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 slug parameter is documented in the schema, but the optional 'description' parameter has no schema description and the tool description does not mention it either. With only 50% schema coverage, the description should compensate for the undocumented parameter, and 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 states a specific verb ('Mint') and resource ('a public URL'), immediately distinguishing it from reading/list tools and other creation tools. It also explains what happens to deliveries ('become events you can await on'), connecting it to the sibling 'await' tool and making its purpose unmistakable.

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 gives an explicit 'When to use' context: when a third-party service offers a callback and the caller has nowhere to receive it. It does not name alternatives or explicit when-not-to-use conditions, but the guidance is clear enough for an agent to select this tool appropriately.

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