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

Beyond the readOnly/openWorld annotations, the description discloses a critical output behavior: it deliberately omits answers and explanations to avoid leaking them, and a seed makes draws reproducible. It also identifies the external source with a URL. A small gap is that the exact return shape or format is not described.

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 core behavior is front-loaded in the first sentence and the 'WHY DELEGATE THIS' section earns its place by helping tool choice. It is slightly redundant ('curated bank' then 'curated, human-written question bank') and the direct-URL note could be trimmed, but overall it is tight.

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?

For a read-only tool with no required parameters and no output schema, the description covers the important context: no answers/explanations, reproducibility, delegation rationale, and direct alternative. It does not spell out the exact question format, but the phrase 'practice questions' plus the answer-routing to vocab_check covers the essential selection and invocation needs.

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 description only restates the seed's reproducibility, which the schema already documents, and leaves theme and difficulty meanings to their enum names. Schema coverage is 50%, so it is not under the low-coverage threshold that would force the description to compensate, but the description adds little parameter-level meaning.

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 first sentence names a specific action and resource: 'Draw words-in-context practice questions from a curated bank.' It further distinguishes itself by stating the response contains no answers or explanations and pointing to vocab_check, which separates it from the relevant sibling.

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 an explicit delegation rationale ('curated, human-written question bank' vs generated questions that 'frequently have two defensible answers') and names alternatives: vocab_check for answers and the direct Words in Context service. This is enough for an agent to decide when to use this tool.

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