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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: daily refresh cadence, dropped fields (operator comments and rating artwork), the preview cap of 5 rows and 20 calls/day without a key, and 1-credit cost with a key. This is exactly the behavioral detail an agent needs.

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-loads what the tool returns before touching operational details (filters, cost, limits). Dense but each clause earns its place; only the field enumeration is slightly long-winded.

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?

No output schema, so listing returned fields and the FHRSID key is genuinely useful, and refresh/cost/limit behavior is covered. However, for a 20-parameter tool with zero schema descriptions, the near-total absence of per-filter semantics leaves a real gap an agent must guess at.

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 20 parameters at 0% schema description coverage, the description carries the full semantic burden but explains only two things: q searches all text fields and filters combine with AND. It never clarifies the many filters (scheme_type, outward_code, rating_value, the min/max score pairs, new_rating_pending, pagination bounds), leaving most parameters opaque.

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: querying the official FSA Food Hygiene Rating Scheme file for England, Wales, Northern Ireland and Scotland FHIS. The enumerated returned fields and the FHRSID key make the scope unmistakable, and it is clearly distinguishable from the other query_uk_* siblings.

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?

Explains that filters AND together and that q searches all text fields, plus the geographic coverage (Scotland uses FHIS), which helps an agent decide applicability. It does not name when to prefer this over other sibling datasets or state prerequisites (e.g. API key requirement per plan), so it stops short of explicit when/when-not guidance.

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