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

Beyond readOnlyHint=true, it discloses ordering (oldest first), the paging dimension (by finish time), a PII warning ('Contains personal data: use small pages'), and a hard quota ('30 requests per hour per API key'). These are exactly the operational traits an agent cannot infer from 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?

Dense but front-loaded: what it returns, ordering/paging, then the two warnings, then the endpoint. Nearly every clause earns its place; the endpoint restatement is the only mildly redundant element.

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?

With no output schema, the description must carry return-shape burden, and it does the important parts: ordering, cursor field name for paging, and the optional monitor_events detail. It stops short of describing the result payload fields, which is a minor gap for a personal-data read 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?

Schema coverage is already 100%, so the baseline is 3, but the description adds non-obvious semantics: cursor paging is driven by finished_after_timestamp fed from next_finished_after_timestamp in the prior reply, and there is a 3-month look-back cap noted alongside the schema's 14-day default.

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+resource ('Recent finished results for the exam of ONE link'), and the emphasized 'ONE link' plus the exam scope distinguishes it from the sibling group/link variants. It also pins the exact API endpoint, so an agent knows precisely what is being fetched.

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?

Routes the agent to the source of ids ('ids from classmarker_list_groups_links_exams') and gives paging guidance ('pass next_finished_after_timestamp from the previous reply'). It does not explicitly state when to prefer the group-level siblings instead, so it falls short of full when/when-not coverage.

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