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 behavior beyond that: a 'Moderate cost' hint that helps the agent budget calls, plus a precise characterization of what the payload contains (distractor-level counts, FRQ partial credit).

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?

Three tight sentences that front-load the resource and metrics, then the use case, then the cost note. No filler, though the middle clause enumerating metrics is somewhat dense and slightly overlaps what the output schema likely carries.

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?

With an output schema present, return-value exposition is unnecessary, and the description supplies purpose, a use case, and a cost signal for a single-parameter read tool. The only missing element is routing guidance toward sibling analytics tools.

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% and the single parameter's description already points at list_coursework as the id source. The phrase 'for one assignment' reinforces that assignmentId scopes the call, but adds no format or validity detail 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 resource and scope ('per-question results for one assignment') plus the exact metrics returned: percent correct, per-choice selection counts, and FRQ part-by-part full-credit rates. This clearly separates it from siblings like get_assignment (metadata), get_grading_results (submission-level), and get_class_insights (class-level).

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?

'Use it for which questions went worst?' gives a concrete triggering scenario, which is genuinely helpful. However, it names no alternatives and no exclusion conditions, so the agent must infer on its own whether get_grading_results or get_class_insights is the better call for adjacent analytic questions.

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