UK company profile

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

No annotations are provided, so the description carries the full burden. It usefully discloses the returned fields, a fixed-subset caveat ('a property not listed was not fetched, so do not read its absence as false'), and specific error codes. It does not cover auth or rate limits, but for a simple read tool the behavioral disclosure is strong.

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 sentences, front-loaded with purpose, then output fields, then error behavior. Every sentence earns its place, and the fixed-subset warning is a valuable clarification rather than filler.

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 and no annotations, the description compensates by listing the returned fields, explaining the fixed-subset semantics, and documenting error codes. This is complete enough for an agent to call the tool correctly and interpret the response.

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?

The input schema has 100% description coverage for the single company_number parameter, including format examples and case-normalisation behavior. The tool description adds no additional semantics beyond 'by its number', so the baseline of 3 applies.

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 states a specific verb and resource: 'Get the profile of one UK company by its number.' The scope ('one', 'by its number') implicitly distinguishes it from a search or list tool, but it does not explicitly name or contrast with sibling tools like company_search.

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?

Usage is implied by 'by its number' – the agent should already have a company number. However, there is no explicit guidance on when to use this versus company_search, nor any exclusions or prerequisites. The minimum viable signal is present but alternatives are left to inference.

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