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

Annotations only declare read-only/idempotent safety attributes, so the description must carry the return-shape burden and it does: every figure carries its source document, quoted timetable row, verifiedDate, and previous-year date where available. It also discloses the miss behavior (covered:false with nearest keys), which is genuine behavioral context beyond the 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?

It is long and delivered as a single dense paragraph, which hurts scanning, but the opening sentence front-loads the scope and almost every clause earns its place by defining precise coverage (dates, timetable window, contingency day, late-entry multipliers). The enumeration of specific calendar dates is borderline payload-in-description, keeping it from a 5.

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?

There is no output schema and no annotation coverage of return structure, so the description must explain what comes back — and it does, including per-figure provenance fields, the quoted source row, verifiedDate, and the previous-year fallback. Nothing needed to invoke or interpret the result 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 coverage is 100% so the baseline is 3, but the description adds real meaning beyond the schema: omission of kind defaults to the listing, board values are given as aliases (pearson/edexcel, wjec/eduqas), and qualification is explained as returning figures common to both when either value is supplied.

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?

Names the specific resource (UK exam calendar dates) and enumerates precisely which categories it covers: results days, summer 2027 timetable, entry deadlines, and specification changes, with named sources (JCQ, AQA, Pearson Edexcel, OCR, WJEC/Eduqas, SQA, Ofqual, DfE). An agent knows exactly what this tool returns without guessing.

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?

Explicitly states the accepted input kinds, that omitting kind returns the listing, and that an unknown kind/board/qualification yields covered:false with nearest keys. There are no sibling tools to route against, so the conditional behavior is the only usage guidance needed, and it is stated clearly.

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