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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior. The description adds genuinely useful context beyond them: the per-call cost of 1 credit and the jurisdictional scope (UK register). It does not describe what a match looks like or how results are returned.

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?

Two compact sentences, front-loaded with the core action, then use cases, then cost in parentheses. Every clause carries information; nothing is redundant.

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 read-only lookup backed by full annotation coverage and a fully described two-parameter schema, the description covers action, scope, use cases, and cost. The only minor gap is what a returned record contains, which is not disclosed anywhere since there is no output 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 100%, so the schema already documents both the name and limit parameters. The phrase 'by name' reinforces that name is the primary lookup key but adds no format, aliasing, or matching-behavior detail 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?

States a specific verb and resource: search the UK register of disqualified company directors by name. The 'disqualified' register is clearly distinguished from sibling officer tools like company_officers and officer_appointments, though the contrast is implied rather than stated.

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?

Gives clear contexts for use — KYB, onboarding, fraud screening, and checking whether a person is banned from running a company. No explicit exclusions or named alternatives, so it stops short of the top band.

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