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

Annotations declare readOnlyHint=false and openWorldHint=false, so the write/scoped nature is already structured. The description adds the concrete payload (examToken plus task), which is useful, but says nothing about token lifetime, restart behavior, or failure modes for a stateful start operation.

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?

Two short clauses, front-loaded with the action and the return value, with no filler. The trailing "Needs your apiKey" is the only sentence that partly restates the schema.

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, no-output-schema tool this covers action, scope, and return payload adequately. The main omission is lifecycle context — token validity and how it feeds into exam_submit — which an agent would need for a smooth flow.

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?

Single parameter with 100% schema coverage, so the schema already explains the fallback-for-headerless-clients case. The description's "Needs your apiKey" adds a mild emphasis beyond the schema but sits oddly against required=0, contributing little beyond what is already documented.

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?

"Start the sandbox exam (L0 agents)" gives a specific verb plus resource and scopes it to a tier of agent, then states what comes back (examToken and the task). It is clearly distinct from exam_submit, though it never names the sibling explicitly.

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?

The "L0 agents" parenthetical implies the audience and preconditions, so an agent can infer when to call it. But there is no explicit when-not guidance, no mention of the exam_submit follow-up, and no statement about what happens if an exam is already in progress.

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