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

Annotations already cover the read-only, closed-world, non-destructive profile, and the description adds real behavior: the question is randomly selected from published items, it comes with a link to answer under the real timer with scoring, and it deliberately never exposes answers or model responses. Minor remaining gap: nothing about rate limits or what happens for an invalid taskType slug beyond the schema pointer.

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?

Front-loaded with the use case, then output, then exclusions and the alternative. Slight redundancy between "It never returns answers or model responses" and "Do not use it to check an answer", which cover overlapping ground.

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 two-parameter read tool with an output schema and full annotation coverage, the description supplies everything an agent needs: trigger conditions, returned content, the scoring link, an explicit no-answers guarantee, and routing to the correct sibling.

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%, so the baseline is 3, but the description's examples pair the two parameters meaningfully (exam "PTE"/"TOEFL" with task kinds like Write Essay and listening), clarifying how exam and taskType interact. The valid-slug guidance directs the agent to exam_overview, though that lives in the schema rather than the description.

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 ("Returns one random published question") plus scope ("for an English exam task") and enumerates the returned payload. It immediately separates itself from speak_practice and from answer-checking tools.

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?

Gives concrete trigger examples ("give me a PTE Write Essay prompt", "a TOEFL listening question"), an explicit exclusion ("Do not use it to check an answer; it only serves questions"), and a named alternative with the exact condition that selects it ("For PTE Read Aloud or Describe Image, use speak_practice instead").

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