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 new behavioral context: results are returned in start-time order, the exact fields returned, and the auth prerequisite ('Cotlet API key with access to this app'). Pagination/result-size behavior is the only thing left unsaid.

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 with the resource and the returned fields, which is good. However, it repeats the same field list twice ('time, instructor, capacity and open spots' then again with class_id), so not every sentence fully earns its place.

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 read-only list tool with no output schema, the description usefully enumerates the returned fields, ordering, and auth requirement. With 100% schema coverage on inputs and annotations covering safety, this is nearly complete; only paging/limits are unaddressed.

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 from/to, program_id and location_id, including the 'default same as from' behavior. The description restates the date-range and filter semantics but adds no format, ID-source, or edge-case detail beyond the schema, so the 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+resource ('list classes') and immediately names the returned fields (class_id, time, instructor, capacity, open spots). It is clearly distinguishable from its Zen Planner siblings book_class, get_class_roster, and cancel_reservation, which it explicitly routes to via class_id.

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 concrete context: scope by date range, narrow with location_id or program_id, and feed the resulting class_id into book_class or get_class_roster. This is clear usage guidance, though it never states when NOT to use it or what distinguishes it from other listing tools.

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