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

Goes well beyond the readOnlyHint annotation: it discloses the pagination direction (oldest first), the maximum 3-month look-back, the personal-data exposure and the corresponding advice to use small pages, and the cost of one of 30 requests/hour per API key. It also enumerates the returned fields, so an agent knows exactly what it receives.

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 purpose and pagination order in the first clause, then the cost/PII cautions and the endpoint. The long comma-separated field list is dense but it replaces a missing output schema, so it earns its space; overall it is a single packed block rather than cleanly separated sentences.

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 and only a readOnlyHint, the description compensates fully: returned fields, ordering, look-back bound, rate-limit cost, PII handling advice, and the underlying GET endpoint. Nothing an agent needs in order to call this correctly is missing.

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 description coverage is 100% and the schema already explains limit, include_monitor_events, and finished_after_timestamp including the next_finished_after_timestamp paging trick. The description only restates the paging order ('oldest first') and adds no parameter semantics beyond the schema, so the baseline 3 applies.

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 with explicit scope: 'Recent finished test results taken through the key's links (all links, all exams), oldest first, PAGED by finish time.' The 'all links, all exams' qualifier implicitly separates it from classmarker_recent_link_exam_results and the group variants, though no sibling is named outright.

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?

Usage is implied by scope rather than stated: the agent must infer that this is the tool for cross-link/cross-exam result retrieval while the sibling covers single exams. There is no explicit 'use X instead when Y' routing, though the PII caution ('use small pages') and the 3-month look-back do constrain legitimate calls.

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