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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds genuine context beyond that: answer keys are teacher-only material (an access/permission note) and the call is cheap (a cost signal), plus it discloses that stimulus sets expand to all linked questions and keys.

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?

Four short sentences, front-loaded with the return contents and with zero filler; each sentence (return shape, stimulus-set expansion, teacher-only keys, cost) carries distinct information.

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, so return-value detail is not strictly required, and the description still adds the teacher-only access caveat and stimulus-set expansion behavior. It is broadly complete for a read-only tool, though it says nothing about permissions required or about pagination/limits implied by 'cheap'.

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?

With only 50% schema description coverage, the description carries part of the burden, yet it says nothing about either parameter. questionId is documented in the schema (pattern + example), but subjectSlug has no description anywhere, and the description does not clarify how these two strings combine.

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 (returns one bank question) and enumerates what comes back: stimulus, choices, marked correct answer, and explanation. It is clearly distinguishable from list/search siblings, though it doesn't name them explicitly; the schema description points to search_question_bank as the source of the id.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no alternative is named (e.g., get_frq, get_questions_for_materials, search_question_bank). The single word 'Cheap' hints at a cost tradeoff but leaves the agent to infer when this preview is preferable to a heavier fetch.

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