list_domains

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

With no annotations, the description's 'GET /domains' at least signals a read-only list operation. However, it does not disclose pagination behavior, authentication needs, or response characteristics, so the behavioral burden is only partially carried.

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 with no wasted words. It states the operation and endpoint efficiently, which is appropriate for a simple listing tool.

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?

There are no annotations, no output schema, and no parameter descriptions, so the description is too thin to fully support invocation. An agent can make a basic call, but cannot correctly use pagination or understand what the response contains.

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 0% description coverage for the three parameters (after, limit, before), and the description adds no parameter meaning. The description was the only place to explain these parameters, and it does not, leaving cursor pagination semantics undocumented.

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 clear verb and resource: 'List sender domains', and the parenthetical 'GET /domains' reinforces the exact operation. It is easily distinguished from sibling tools like get_domain or create_domain.

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 no guidance about when to use this tool versus alternatives, such as get_domain for a single domain or verify_domain for verification. It only states what the tool lists, leaving the agent to infer the appropriate context.

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