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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real behavioral context beyond that: the 31-day maximum range and the auth requirement ('user's Cotlet API key with access to this app'), which the annotations do not convey. Pagination/return-shape details are still absent.

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 wasteful: the opening fragment ('Calendar appointments in a date range, with client, service, staff and price') is then repeated almost verbatim in the second sentence. The redundancy costs space that could have gone to sibling routing.

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, the description helpfully names the fields returned, plus the range cap and the auth prerequisite. For a simple 3-param read tool this is close to complete, missing only return-shape/pagination expectations.

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 three parameters are already documented; the description's mention of the 31-day range and the staff filter largely restates the schema ('at most 31 days after from', 'Only this staff member'). Baseline 3 applies when the schema carries the meaning.

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 and resource ('Lists calendar appointments between two dates') and enumerates the payload fields (client, service, staff, price). It is clearly distinct from write siblings like thryv_book_appointment, though it never names an alternative explicitly.

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 useful usage cue ('Filter by staff member to see one person's calendar') and the 31-day range constraint, but no when-to-use/when-not guidance and no routing to siblings such as thryv_get_client or thryv_list_invoices.

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