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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine behavioral context by equating the returned data with the participant list any enrolled student can see, clarifying authorization/visibility scope. It stops short of noting pagination or volume, but the additions are meaningful.

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?

Two sentences, front-loaded with the core action and scope, with no filler. The phrasing is slightly informal but each sentence carries information, so it is appropriately sized.

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 simple single-parameter read tool with an output schema and annotations covering safety, the description supplies the necessary purpose and visibility note. Nothing critical is missing, though pagination and filtering behavior are not mentioned.

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%, and the schema already explains course_id as a 'PLATO/Moodle numeric course id, e.g. from list_courses'. The description adds nothing beyond the schema's parameter documentation, 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?

The description states a specific verb and resource ('Get the list of users enrolled in a course'), clarifies the population ('classmates and instructors'), and notes it includes 'their role'. The resource is distinct enough from siblings like get_user_profile or get_my_course_groups to be identifiable, though no sibling is named 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?

The second sentence frames visibility ('Same data visible in PLATO's own participant list to any enrolled student'), which implies the use case, but there is no explicit when-to-use, when-not-to-use, or named alternative. Usage is left largely to inference.

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