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

Beyond the readOnly and idempotent annotations, it discloses ordering (most active first), result fields, and eligibility limits (only indexed organisations; no sole traders). It does not cover pagination or result limits, so it is not fully exhaustive.

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?

Three compact sentences front-load the purpose, then cover return fields, downstream tools, ordering, and eligibility. There is no redundant or filler text.

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 compensates by naming the returned fields and ordering. For a two-parameter read-only lookup, the eligibility constraints and downstream use make the definition complete enough to invoke correctly.

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%, so the name minimum length and type enum/default are already documented. The description adds useful query examples but little additional parameter semantics beyond the schema.

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?

The description gives a specific verb and resource: find contracting authorities and companies by name or prefix. It includes concrete examples and distinguishes the result from sibling tools by saying the returned slug/URL feeds get_buyer and get_company_awards.

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?

It clearly positions the tool as a lookup step before get_buyer or get_company_awards and explains the optional buyer/company filter. It does not explicitly exclude other lookup approaches, but the downstream usage context is strong.

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