ecp_domains_list_additional

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

With no annotations, the description carries the burden, and it clearly conveys a read-only listing operation scoped to addon domains. It does not mention response format or error behavior, but for a zero-parameter list operation these are less critical.

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?

A single sentence with no filler. The key distinction ('additional (addon) domains only') is front-loaded, and every word earns its place.

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?

For a zero-parameter list tool with no output schema, the description is sufficient to select and invoke it correctly. It could add a note about the return shape, but the core information is present.

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 no parameters, and the schema documents this completely with empty properties and 100% coverage. There is nothing for the description to add about parameters; baseline 4 applies.

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?

States a specific verb ('List'), the resource ('additional (addon) domains'), and an explicit exclusion ('excluding the primary domain'). This clearly differentiates it from ecp_domains_list_all and other domain-related tools.

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 words 'only' and 'excluding the primary domain' tell the agent when this tool is appropriate: when addon domains are needed and the primary domain is not. It does not explicitly name ecp_domains_list_all as the alternative for full domain lists, but the context is clear.

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