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

Goes beyond the annotations by disclosing that the block 'reaches no client' (no notification is sent), that it is reversible ('you can remove the block in Booksy'), and that it 'runs without asking first'. This adds genuine behavioral context on top of readOnlyHint=false/destructiveHint=false, though it doesn't cover auth scope or failure modes in depth.

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 core idea ('block a period so no one can book it') is stated and then immediately restated in the second sentence, which is largely redundant. The auth note is useful but the repetition wastes space in an otherwise short description.

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 mutation tool with no output schema, the description covers the key concerns: reversibility, absence of client notification, no-confirmation behavior, and the required Cotlet API key access. Little an agent needs in order to call 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?

Schema description coverage is 100%, so the schema already documents all four parameters including the ISO 8601 date-time formats. The description adds nothing parameter-specific beyond tying the operation to a staff member, so baseline 3 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?

States a specific verb (Block) and resource (time in a staff member's calendar) with the effect made explicit ('so no one can book it'). An agent can distinguish this from booksy_create_appointment or booksy_find_open_slots without opening any 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?

The description explains what the block is analogous to ('like time off set in the app') and that no confirmation is needed, but it never states when to choose this over alternatives or any explicit exclusions. Usage is implied rather than guided.

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