get_company

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

Annotations already declare readOnlyHint and openWorldHint, and an output schema exists, yet the description still adds value: it identifies the live external authority, advertises the substantive fields (status, incorporation date, SIC codes, insolvency history, overdue accounts) and the source_url that enables citation. It omits edge-case behavior such as what happens for an unknown or malformed company number, which keeps it below a 5.

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 tight sentences: the lookup definition with example comes first, then the returned fields, then the usage constraint. Every clause carries information and nothing is repeated from the schema or annotations.

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?

Annotations cover the safety profile and the output schema covers return structure, so the description only needs to add selection and input-format guidance, which it does. The one gap is failure behavior for invalid or not-found company numbers, which an agent might reasonably need before committing to a call.

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% — the schema only says 'Company Number' as a bare string — so the description must compensate, and it does by giving the concrete example '00445790', conveying zero-padded numeric format. It does not state whether the leading zeros or any prefix are mandatory, so it falls short of complete semantics.

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 (look up a UK company), names the authoritative source (Companies House), and the lookup key (company number). This is clearly distinct from the sibling tools list_profiles, search_tenders and score_tenders, so an agent can select it 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?

Explicitly instructs 'Use before stating anything about a company's status; never infer it', which is a concrete when-to-use rule plus a prohibition on guessing. It does not name an alternative tool for the case where the company number is unknown, so it stops just short of full routing guidance.

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