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

Annotations declare readOnlyHint=true, so safety is covered; the description adds genuinely new behavior — default page size of 20 and 'newest first' ordering — which an agent needs to reason about pagination and result order. It stops short of describing total counts or response shape.

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, no filler; the resource and ordering are front-loaded before the endpoint citation.

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, three-parameter list tool with full schema coverage and annotations covering safety, the description supplies what is missing (defaults, sort order). Only the absence of any return-shape hint keeps it from a 5, and no output schema exists to cover that.

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%, so the baseline is 3; the description adds the default items-per-page value (20) that the schema's 1-200 range does not state, giving marginally more than the schema alone.

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 the exact resource (users enrolled in one course) and a distinguishing scope, so an agent can tell it apart from list_users and list_user_courses without reading the schema. Also cites the underlying endpoint, anchoring semantics.

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 implied by the resource phrasing (listing enrollees of a single course), but there is no explicit when-to-use/when-not-to-use guidance and no alternative named for the adjacent list_users / list_user_courses siblings.

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