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

Annotations already establish readOnlyHint=true, destructiveHint=false and openWorldHint=true. The description adds two things annotations cannot: the auth prerequisite ('Needs the user's Cotlet API key with access to this app') and, since no output schema exists, an inline description of the returned payload.

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 opening and second sentences are near-duplicates ('Your service menu with duration, price and the staff who offer each' vs 'Returns the services on your Booksy menu with duration, price and the staff members who offer each one'), and the 'Booksy:' prefix repeats the title. The downstream-usage and auth sentences do earn their place, but the tool wastes its lead on 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 parameterless read-only listing tool with no output schema, the description covers what is returned, where the IDs are reused, and the credential requirement. Nothing essential to calling it correctly is missing.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless tool applies. The schema is empty by design and consistent with a plain listing call.

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 names a specific verb and resource ('Returns the services on your Booksy menu') and enumerates the returned fields (duration, price, staff), which lets an agent distinguish it from siblings like booksy_list_staff and booksy_list_clients without opening a schema.

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?

It explicitly states where the returned data is consumed ('Use the service ID in find_open_slots and create_appointment'), giving clear workflow context. It does not name what this tool should be used instead of, but no sibling duplicates its function, so the gap is minor.

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