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

Annotations already declare readOnly/not-destructive/openWorld, so the safety profile is covered. The description adds genuinely useful behavior: results ordered earliest-first and an auth requirement ('Cotlet API key with access to this app'). It does not cover pagination/limits, keeping it from a 5.

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?

Four sentences, front-loaded with the resource and scope, and each carries distinct information (fields, range, filter, id/auth). Slightly long but no wasted filler.

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 a fully described schema and no output schema, the description covers scope, ordering, item contents, auth needs, and sibling linkage. Nothing an agent needs to invoke 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 baseline is 3. The description adds meaning beyond the schema by framing the date range ('between two dates, earliest first') and explaining the instructor filter's purpose ('find all classes of one person'), which the schema only labels generically.

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 on a location's schedule) and enumerates the fields returned: time, class type, instructor, open spots. It also distinguishes itself from the roster/booking siblings by noting the class_id they consume, so an agent can tell it apart from get_class_roster.

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 clear context: returns classes of one location between two dates, and 'filter by instructor to find all classes of one person.' It references the roster and booking tools that consume class_id, but stops short of explicitly stating when NOT to use this tool vs those siblings.

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