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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description only needs to add non-obvious behavior. It adds that the tool returns domain state, but does not mention filtering, pagination, or how 'own domains' differs from connected domains.

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 that states the resource and the returned information with no filler or redundant details. It is appropriately sized for the tool's simplicity.

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 presence of an output schema, read-only annotations, and a fully documented single parameter, the description is almost complete. It could be slightly stronger by explicitly saying 'list' the domains, but overall it covers the essential context for a simple list operation.

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 single required parameter 'project' is fully documented in the schema with 100% coverage, including slug/id format and how to derive a slug from my_projects. The description adds no additional parameter semantics, so the baseline 3 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?

The description conveys the resource (project's own domains) and the data returned (their state), and the tool name 'list_domains' supplies the verb. It implicitly distinguishes this from sibling tools like connect_domain and check_domain, though it could be more explicit about the listing action.

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?

There is no guidance on when to use this tool versus alternatives such as check_domain or connect_domain. No exclusions, prerequisites, or alternative references are provided, leaving the agent to infer usage from the tool name and sibling names.

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