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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine domain context beyond that: what the payload contains, that students join via assignment links and 'there are no class codes', and a cost hint ('Cheap'). It stops short of error behavior for a bad classId.

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 dense sentence front-loads the resource and payload contents, followed by a short domain note and the terse 'Cheap.' No filler, though the telegraphic fragments are slightly choppy.

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 low-complexity single-id read with full schema coverage, an output schema, and rich annotations, the definition covers purpose, payload shape, and a cost cue. The only real omission is explicit routing against sibling getters.

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?

One parameter with 100% schema description coverage, including the 24-hex pattern and its origin ('Class id from list_classes'). The description adds no parameter-level meaning beyond the schema, so the 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?

States a specific verb+resource ('One class in the teacher's workspace') and enumerates the payload: subject, roster with handles, assignment defaults, and student links for open assignments. This distinguishes it from list_classes and get_class_insights by scope (single class vs. collection vs. analytics).

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: it is a single-item getter, and 'Cheap' hints it should be preferred over heavier alternatives, but no when/when-not or sibling routing (e.g., vs. get_class_insights or get_assignment) is stated. The classId lookup chain to list_classes lives in the schema, not the description.

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