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

Annotations already establish readOnly, idempotent, non-destructive and closed-world behaviour, so the bar is lower. The description adds real context beyond that: the response is a practice card including figures and an answer surface, and the model receives the full question text so it can hint without revealing the answer. Minor gaps remain (what happens if the part/question is absent, no pagination or size notes).

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 the primary action and artifact, with no filler. The middle sentence about hints is slightly indirect in wording ('gets the full question so it can give hints without giving the answer away') but still earns its place by explaining the exposure model.

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 no output schema, the description usefully characterises the return value (practice card, figures, answer surface). Combined with full schema coverage and clear read-only annotations, an agent has enough to call it correctly; only edge-case behaviour for missing question/part identifiers is unaddressed.

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%, so paper_id, question and part are already well documented with formats and examples. The description adds no additional meaning about these parameters (e.g. how paper_id relates to find_past_paper output beyond what the schema says), so the baseline of 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 a concrete verb and resource ('Show one past-paper question as a practice card') and specifies the rendered artifacts (figures, answer surface), which is more than a restatement of the title. It does not, however, distinguish this from sibling tools like get_question or find_questions_by_topic, so an agent cannot tell from the description alone whether this is the retrieval tool or a presentation variant.

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?

It implies the practice/study context and explicitly routes the marking step to mark_answer, which is genuinely useful. It stops short of stating when to prefer this over get_question or find_questions_by_topic, and gives no prerequisites or exclusions, leaving the main sibling decision to inference.

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