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 value by flagging the PII sensitivity and the course-scoping constraint that governs whether the lookup succeeds, going beyond the annotations.

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?

A single tight sentence with the scope constraint front-loaded. The 'see docs/pii_review.md' pointer is a dangling reference an agent cannot follow, slightly diluting an otherwise efficient statement.

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?

An output schema exists and the input schema is fully documented, so the description only needs to carry scope and privacy context, which it does. The one gap is behavioral: it doesn't say what happens when the accounts don't share the course (error vs empty).

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 that omitting userid returns the caller's own profile and that course_id must be shared. The description reinforces the 'shared course' semantic but contributes no format or edge-case detail beyond the schema.

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 and resource ('Get a user's profile') plus a scope qualifier ('scoped to a shared course'), and explicitly negates a plausible misreading ('not a global user search'). It stops short of naming the actual sibling that handles enrolled users (get_enrolled_users), so differentiation is partial.

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 parenthetical clarifies the boundary condition (course-scoped, not global), which implies when to use it. However, it never states when to prefer get_enrolled_users or the account's own profile path, and defers to an external doc the agent cannot read.

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