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

The annotations already cover read-only, idempotent, and open-world behavior, so the bar is lower, but the description still adds useful meaning: counts cover only reviewed questions, and the API doesn't split them by question type. The mention of a credit cost also gives context beyond the annotations.

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?

The definition uses one front-loaded sentence that gives the core count behavior and difficulty split, then a clarifying sentence and short parentheticals. It is dense but purposeful, with no filler.

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?

There is no output schema, so the description usefully explains the shape of the result: counts by difficulty, with multiple-choice and true/false combined. It omits details such as return format or whether counts can be zero, but the definition is otherwise sufficient for a single-parameter query tool.

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?

The schema already documents the single category parameter fully, including accepted IDs and name examples. The description only implies category scoping ('one category') and adds no format or syntax details 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?

The description states a specific verb and resource: it counts reviewed questions held in one category, split by easy/medium/hard. This is clearly distinguishable from siblings such as trivia_questions and trivia_true_false, which fetch questions rather than return counts.

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 gives a concrete use case: plan a quiz round without requesting more questions than exist, with the note that some categories hold only a few dozen hard questions. It doesn't explicitly name trivia_questions as the alternative for when you actually want the questions, but the context is still clear.

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