resend_list_domains

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

With no annotations, the description carries full weight for behavioral disclosure. It only states 'List domains' without confirming read-only nature, authentication requirements, rate limits, or output format—leaving important behavioral traits unspecified.

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 sentence of 31 characters, which is concise but borderline terse. It could include a bit more context (e.g., output scope) without becoming verbose, so it's adequate but not exemplary.

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 lack of an output schema and only one optional parameter, the description should clarify what 'domains' refers to and whether the list is complete or filtered. It fails to provide this context, leaving the tool's behavior under-specified.

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 one parameter (api_key) with no description (0% coverage). The description does not mention or explain the api_key parameter, adding no meaning beyond the schema itself.

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 ('List') and resource ('domains configured in Resend'), making the tool's purpose immediately understandable. It is distinct from sibling tools like resend_get_email and resend_send_email, which target different actions.

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 guidance is provided on when to use this tool instead of alternatives, nor any context on prerequisites or scenarios where listing domains would be appropriate or inappropriate.

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