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 genuinely useful behavioral content: the 'today' time scoping (with no date parameter, the agent knows it cannot query arbitrary dates) and the exact response contents, which no output schema provides.

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?

One front-loaded sentence plus the REST path; every element earns its place and the returned-field inventory is efficient. The telegraphic 'Who is in a class today:' opening is slightly terse but not padded.

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 small read-only tool with no output schema, the description compensates well by spelling out the response fields. Remaining gaps are minor: no mention of pagination, behavior for an invalid/unknown class_id, or whether 'today' is timezone-dependent.

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 coverage is 100% with a single well-documented class_id parameter, so the description need not carry this burden. It only echoes the id via the endpoint path '/v1/Classes/{classId}/roster', adding no format or sourcing detail beyond the schema — baseline 3.

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 resource and verb-equivalent ('Who is in a class today') and then enumerates the returned fields (class name, start time, location, room, instructors, roster). This distinguishes it reasonably from jackrabbit_get_class and the list_* siblings, though it never explicitly says how it differs from get_class.

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?

Usage is only implied by 'Who is in a class today' — an agent can infer this is the call for attendance/roster questions. There is no explicit when-to-use, no named alternative (e.g. jackrabbit_list_attendance vs jackrabbit_get_enrollment), and no statement of prerequisites beyond the required class id.

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