list_registrar_domains

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, but it only states the operation. It doesn't disclose whether results are paginated, whether any filtering is possible, what fields are returned, or whether the account must have Registrar configured. The verb 'List' weakly implies read-only behavior, but nothing else about the tool's runtime behavior is revealed.

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 six-word sentence with the verb front-loaded and zero filler. Every word earns its place, and the brevity is appropriate for a simple one-parameter list operation.

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?

Despite the tool's low complexity (1 parameter, no nested objects, no output schema), the description leaves notable gaps: no pagination behavior, no mention of the get_registrar_domain sibling for singular retrieval, and no indication of what distinguishes a Registrar domain from the broader set of account zones. The absence of annotations and an output schema raises the burden on the description, which it does not fully meet.

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?

Schema description coverage is 100%, with account_id documented as 'The account ID', so the schema already handles parameter meaning. The tool description adds no parameter-level detail beyond this, which is acceptable at the baseline 3 since the schema does the heavy lifting.

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 pairs a specific verb ('List') with a specific resource ('domains registered with Cloudflare Registrar'), making the operation and scope clear. It distinguishes itself from sibling tools like list_zones and list_dns_records by naming the Registrar product context, though it doesn't explicitly differentiate itself from the singular get_registrar_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?

No guidance is provided on when to use this tool versus alternatives. There is no mention that get_registrar_domain exists for single-domain lookups, no contrast with list_zones (which lists all zones in an account), and no indication of prerequisites such as having the Registrar product enabled.

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