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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds useful context by disclosing that results carry verification status and by naming the underlying REST endpoints, but it says nothing about pagination behavior or ordering beyond what the schema implies.

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 front-loaded sentence states the resource, scope, and returned fields, followed by endpoint paths in parentheses. It is efficient, though the raw endpoint strings are of marginal value to an agent that already has the tool and schema.

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 read-only list tool with 100% schema coverage and annotations covering safety, the description is nearly sufficient. It conveys scope and returned content; only richer output/pagination expectations would make it fully complete, and those are minor 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?

Schema description coverage is 100%, so all four parameters (page, cursor, teamId, per_page) are already documented in the schema. The description only restates the account/team scope that teamId covers, adding no new syntax or constraint detail. Baseline 3 is appropriate.

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 and resource ('List custom domains') plus the scope (account or team) and a bonus detail about returned content ('with verification status'). No sibling covers domains, so an agent can identify this tool's unique purpose immediately.

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 implies when each scope applies by pairing 'account (or a team)' with the two endpoint variants, which gives some routing signal. However, it never states when not to use this tool or how it relates to any alternative, so usage is only implied rather than explicit.

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