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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: pages are cursor based, and it requires the user's Cotlet API key with access to this app. That auth and pagination detail goes beyond the structured fields.

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-loads the resource and returned fields, then covers filters, pagination, and auth in a compact set of sentences. The opening fragment 'Booksy: Clients with contact details and last visit' slightly duplicates the following sentence, a minor redundancy.

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 list tool with no output schema, the description still conveys what is returned (contact details, last visit date), how paging works, and the auth prerequisite, which is sufficient to call it correctly. Only the explicit relationship to sibling client tools 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 description coverage is 100%, so all four parameters are already documented in the schema, making 3 the baseline. The description adds marginal value by noting cursor-based paging and restating the query/not-visited filters, but supplies no syntax or format detail beyond the schema.

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 (lists) and resource (clients from your client list) plus the fields returned (contact details, last visit). It is distinguishable from booksy_get_client and booksy_add_client by the plural verb and list scope, though it never explicitly names a sibling to disambiguate.

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 usage by describing two filtering modes (search by name/email/phone, or filter by not-visited days), which tells the agent when the filters apply. However, it gives no explicit guidance on when to choose this over booksy_get_client or other client tools, leaving the alternative selection to inference.

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