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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered without the description. The description adds one useful piece of substance beyond structured data: the shape of what comes back (contact details, visit counts, last visit, client groups). It says nothing about pagination behavior or the cost/size of a full listing.

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?

One short fragment with no waste, but it is not front-loaded with an action or a scope statement, so the reader has to supply the verb and purpose. Brevity here is under-specification rather than efficient packaging.

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?

The tool is simple (4 optional params, no nesting, no output schema) and annotations plus schema cover most requirements, and the description partially compensates for the missing output schema by naming returned fields. It still omits pagination/cursor workflow and the not_visited_days use case for re-engagement, which an agent would want before calling.

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 limit, query, cursor and not_visited_days are already documented in the schema with defaults and semantics. The description mentions none of them and adds no filtering, formatting or interaction detail, so the baseline 3 for schema-carried semantics 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 is a noun phrase naming the resource and its payload ('Clients with contact details, visit counts and last visit, plus Booksy's client groups') but never states the operation; the 'list' verb only comes from the name/title. It also fails to distinguish this tool from the sibling find_client and get_client, despite list_clients itself accepting a 'query' search parameter that overlaps with find_client.

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 when-to-use or when-not guidance and no mention of alternatives, even though find_client, get_client and list_clients all return client data and the description gives no basis for choosing. The only implicit cue is the word 'Clients' scoping it to the client resource.

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