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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, yet the description adds substantial context: the study guide is the authority, no correction via current events, no invented questions, no personal data collection, the unofficial/disclaimer status, unvetted additions must be labelled, and multi-version tests must not be assumed. These are meaningful behavioral and compliance traits beyond the structured hints.

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?

Purpose and return values are front-loaded, and the six numbered rules are individually meaningful rather than filler. The list is long and slightly repetitive (rule 2 overlaps with rule 5), but each sentence earns its place given the compliance sensitivity.

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 carries the return-value burden and does so fully: correctness, correct option, vetted explanation, guide page, disclaimer, and version note. It also supplies the authoritative-source and privacy constraints an agent needs to respond correctly.

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 each parameter already carries its own documentation (lang default and source, choice letter, country code, question_ref origin). The description adds only the reinforcement that question_ref must come from get_practice_questions; baseline 3 is appropriate.

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 and resource: checking the person's answer to one question from get_practice_questions. It also enumerates what is returned (correctness, correct option, vetted explanation, study-guide page), which makes it unmistakable against siblings like get_practice_questions or list_tests.

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?

Explicitly constrains input to a question_ref returned by get_practice_questions, establishing the prerequisite chain. It does not spell out an explicit when-not-to-use or compare against alternatives beyond that one constraint, so it falls just short of a 5.

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