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

Annotations declare the safe-read profile (readOnlyHint=true, destructiveHint=false), so the description correctly doesn't need to justify safety. It adds real value beyond the annotations by disclosing the auth requirement (a Cotlet API key with app access) and by detailing the shape of the returned record in the absence of an output schema.

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?

Front-loaded and short, but the first sentence ('contact details, memberships and family members') is largely restated by the second sentence, which just adds 'start dates' and 'linked to the account'. One of the two enumerations is redundant filler.

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?

With no output schema and no annotations about returns, the description carries the burden of explaining what comes back, and it does so adequately (contact details, memberships with start dates, family members). Auth requirement is also covered; only the relationship to list_members for sourcing the ID is left unstated.

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 coverage is 100% and the single person_id parameter is fully documented in the schema as coming from list_members. The description adds nothing about the identifier format or constraints, so the baseline 3 applies – the schema does all the parameter work.

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+resource (get member) and spells out exactly what the record contains: contact details, memberships with start dates, and linked family members. 'Returns one person' implicitly separates it from the list_members sibling, but it never names that sibling, so differentiation relies on inference.

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?

Gives one concrete use case – fetching a phone number or email before contacting someone – which implies the fetch-a-single-record scenario. It offers no guidance on when to use list_members instead, and there is no stated prerequisite beyond the API key (e.g., that the person_id must first come from list_members).

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