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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower, and the description still adds real context: no authentication required, and the response contains the answer key and per-option explanations. It omits how many questions come back and whether the sampler and landing-page sets are merged or distinct.

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 short sentences, front-loaded with what the tool returns, with no filler. The middle sentence on reveal-after-picking is useful but sits awkwardly as a UI instruction rather than a tool-invocation fact.

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 one required parameter, no output schema, and annotations handling safety, the description carries the important burden of describing the payload (stem, options, key, explanations) and does so. The main residual gap is the volume/shape of the question set returned, which an agent cannot infer from anywhere else.

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 examId already documents itself as 'An examId from list_exams.' The description only restates the single-exam scoping ('for one exam'), adding no format or sourcing detail beyond what the schema provides, 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?

The description names the specific resource (free sample questions for one exam, drawn from the landing-page run and the /learn sampler) and states exactly what comes back: the key plus every option's explanation. It is clear enough to separate from most siblings, though it never explicitly contrasts itself with adjacent tools like learn_question, deal_questions, or answer_question.

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?

'No sign-in needed' is an access condition rather than a routing rule, and 'show the stem and options first and reveal the key only after the person picks' is presentation guidance for the returned data. Nothing states when an agent should choose this over the other question-serving tools in the sibling list, so usage is only implied.

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