resend_list_domains

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

No annotations are provided, so the description bears the full burden of transparency. However, it does not disclose behavioral traits such as authentication requirements (beyond the api_key parameter), output format, pagination, rate limits, or side effects. For a listing tool, this lack of detail limits the agent's understanding.

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?

One sentence, no wasted words. It is appropriately concise, though it could benefit from a slightly more structured format (e.g., front-loading the verb-object). Still, it earns a high score for brevity.

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 optional parameter, no output schema), the description is too sparse. It does not explain the return structure, error conditions, or any nuances of listing domains in Resend. This limits the agent's ability to confidently invoke the tool.

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 input schema has a single optional parameter 'api_key' with 0% description coverage. The tool description does not add any meaning to this parameter, leaving its purpose or required format entirely implicit.

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 'List domains configured in Resend' clearly states the action (list) and the resource (domains in Resend). This distinguishes it effectively from sibling tools like resend_get_email or resend_send_email, which deal with email operations.

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 provides no guidance on when to use this tool versus alternatives, nor any prerequisites, exclusions, or context about typical use cases. It simply states what it does without any comparative or conditional advice.

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