lookup_company

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

With no annotations, description fully discloses behavior: default monthly snapshot, absence of dissolved companies, real-time option with API key, and honest 'not found' return. Clearly communicates data freshness and scope.

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?

Description is informative and flows logically: use case, return fields, data source limitations, optional enhancement. Each sentence adds value, though slightly verbose; could be more concise without losing 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 single-parameter lookup tool, description is remarkably complete: explains return fields, edge cases ('not found'), data source, and optional configuration. No output schema needed as return values are enumerated.

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 already describes the 'number' parameter, but description adds value by providing examples and clarifying that spaces/case are ignored, aiding correct invocation. Schema coverage is 100%, so baseline 3; extras justify 4.

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?

Clearly states the tool retrieves a UK company's official registered details by Companies House number, listing specific fields. Distinguishes from siblings (search and validate) by focusing on exact number lookup.

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 advises using this tool instead of relying on model recall, highlighting a key use case. Mentions limitations (monthly snapshot, dissolved companies absent) and optional API key for real-time data. Lacks explicit alternatives but context implies siblings for search/validation.

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