List custom domains

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

The description provides rich detail beyond the readOnlyHint annotation, including the full set of output fields, possible statuses (pending_dns/verifying/live/failed), and the distinction between path and dedicated domains. This gives the agent a clear picture of what information is retrievable and how to interpret results.

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 two sentences but the first is long and dense with field details. It is efficient and avoids unnecessary fluff, though a slight restructuring could improve scanability. Still, every sentence earns its place by conveying essential output and usage information.

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 (0 params, output schema present), the description fully covers the tool's purpose, output contents, and typical usage scenarios. It also cross-references related tools (dropthis_publish, dropthis_list) to help the agent navigate the tool family.

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 tool has 0 parameters, so the schema covers everything. The description adds no parameter-specific detail because none are needed; it focuses on the output and usage. This is appropriate for a no-parameter list operation.

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 explicitly states 'List the account's custom domains' and enumerates the specific fields returned (dom_ id, hostname, mode, status, default flag, mounted drop id). It clearly distinguishes this tool from siblings like dropthis_domains_get, connect, verify, update, and delete by focusing on the list behavior.

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?

It gives explicit use cases: 'check which domain publish lands on by default' and 'find a hostname to pass as domain to dropthis_publish.' It also tells the user to pass a hostname to dropthis_list to see mounted drops, providing clear guidance on when to use this tool and how it relates to alternatives.

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