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

With no annotations, the description carries the full disclosure burden. It does add real value by disclosing the cost ($0.05 USDC) and the scope of the 'lite' response, but it says nothing about auth/permission needs, error behavior, or what happens when both parameters are omitted (required parameters = 0), which is a meaningful gap.

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 short, front-loaded fragments plus a concrete example — very little waste. The telegraphic phrasing ('Upsell', 'red flags') is slightly informal but does not obscure the meaning.

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?

For a two-parameter lookup with no output schema and no annotations, the description covers purpose, fields, cost, and the main alternative reasonably well. It falls short on how the two optional inputs interact and on any failure semantics.

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 0%, so the description must compensate. The included example {number:"00445790"} clarifies the format of 'number', but the 'name' parameter is never mentioned and no guidance is given on whether name and number are alternatives or can be combined.

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 names the resource (a UK company) and enumerates the returned fields: status, SIC, office, compliance overdue, mass-formation check, red flags. It also explicitly distinguishes itself from the sibling 'uk_company', so an agent can choose between them without opening either 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?

It states the use case ('cheap UK company snapshot') and gives an explicit alternative with its own use case ('Upsell uk_company for officers/PSC/filings/charges/insolvency'). The other siblings (company_full, company_research) are not addressed, so routing among the full family is incomplete.

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