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

Annotations already cover read-only/idempotent/openWorld, and the description goes well beyond them: refresh cadence ('refreshed on every republication, most working days'), cost model (1 credit per call), and an unauthenticated preview cap (5 rows, 20 calls/day). These are exactly the operational facts an agent needs before invoking.

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?

One dense paragraph, but front-loaded with the dataset and its scope before cost and auth details. Every clause carries information; only the trailing pricing/preview sentence sits slightly apart from the core purpose.

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 usefully enumerates returned fields, which is the right compensation. The remaining gap is pagination/value-format guidance for a 9-parameter tool, which is left entirely to an undocumented schema.

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 0% across 9 parameters, so the schema carries no meaning on its own. The description partially compensates by naming filterable fields (organisation, town, county, sponsor_type, route, rating) and the AND/q semantics, but says nothing about page/per_page behavior or accepted values for route, rating, and sponsor_type.

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 the specific resource (Home Office register of licensed sponsors for Worker and Temporary Worker routes) and enumerates the returned fields, so an agent can distinguish it from the many sibling query_uk_* datasets without opening the schema.

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 how to use it (filters combine with AND, q searches all text fields) and gives context on data scope ('organisation-level data only', one row per organisation and route), but does not state when to prefer it over the other query_uk_* tools or any exclusions.

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