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

No annotations are provided, so the description bears full burden. It clearly states the tool is paid ($0.02 USDC per call) and provides the exact return shape. It doesn't disclose any destructive behaviors or side effects, but as a read-only data retrieval tool, the key behaviors (live source, cost, structured output) are covered.

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?

The description is two paragraphs: first explaining purpose and output, second stating cost and explicit return structure. It's front-loaded with the core purpose and key details. The repetition of 'returns' could be trimmed, but overall it's efficient.

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?

Given the simplicity (only 2 params, no output schema), the description covers the main points: what data is returned, cost, and the effect of the detail param. It doesn't explain pagination, error handling, or rate limits, but for a single-company profile tool with clear schema, this is sufficient.

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 100%, so baseline is 3. The description adds value by explaining the 'detail' parameter's effect (adds filing history, lifts token cap) and the 'number' parameter's pattern (prefixes for Scotland, NI, LLP). This goes beyond the schema's terse pattern and enum descriptions.

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 clearly states it returns structured JSON data for one UK company, enumerating fields like status, incorporation date, type, SIC codes, etc. It differentiates from siblings by specifying the source (Companies House) and the structured output format, which is distinct from search or other UK tools.

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?

The description mentions it costs $0.02 USDC per call, which signals when to use frugally. It doesn't explicitly contrast with siblings like uk_company_search or uk_company_verdict, but the focus on detailed profile data versus searching or verifying implies its use case. No explicit when-not-to-use guidance is provided.

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