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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond the annotations: no auth key is required and results carry no certification weight — an auth requirement and consequence note that an agent cannot read from structured fields. It stops short of saying whether the exam content is stable across calls or how large it is.

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?

A single front-loaded sentence with the caveats packed into one parenthetical. Nothing redundant, nothing padded.

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 one-parameter read-only tool with no output schema, the essentials are present, and return values need not be described. However, the description leaves open how the returned exam is consumed (presumably via submit_practice_exam) and how to obtain a valid capability value, both of which an agent needs to complete the workflow.

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?

With one parameter at 0% schema description coverage, the schema gives only 'capability: string'. The description clarifies the parameter means a skill, which is a real gain, but it uses different vocabulary than the parameter name and never says what a valid skill identifier looks like or where to get one (list_skills is a sibling but unmentioned).

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 — retrieving the Gym practice exam for a given skill — and contrasts it with the certification path ('never counts toward certification'). It does not name the closely-related siblings start_gym_exam or submit_practice_exam, so the get-vs-start boundary is left to inference.

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?

'no key needed; never counts toward certification' implies the practice/exploratory use case, but there is no explicit when-to-use versus start_gym_exam or when-not guidance. The agent must infer that this is the non-credentialed alternative from the parenthetical alone.

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