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

The annotations already declare readOnlyHint: true and destructiveHint: false, so no contradiction. The description adds behavioral context: it uses GLEIF (free, no key), charges $0.01/call in USDC, and optionally needs a Companies House API key for extra data. This moves beyond the annotations by disclosing the cost, third-party data sources, and optional enrichment behavior.

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 a single, dense sentence with key information front-loaded (purpose, outputs, free source) and optional details later (UK API key, cost). It is concise and wastes no words, though it could be split into two sentences for easier scanning.

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 moderately complex input (array with optional country hints, optional API key) and no output schema, the description covers inputs, optional enrichment, data source, and cost well. It lacks details on the output format or error cases (e.g., what happens if a name is not found), but the annotations and schema provide a solid foundation. Completeness is good but not exhaustive.

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%, but the description still adds meaning: it explains the pipe syntax for country hints, that LEI or UK company numbers bypass name search, and how the optional API key unlocks directors/SIC codes. This exceeds the baseline of 3 by enriching the agent's understanding of input formatting and optional features.

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 the tool turns a company name, LEI, or UK company number into an official registry card with specific fields (legal name, status, jurisdiction, registered address, LEI). It also mentions optional enrichment with UK directors and SIC codes. This purpose is distinct from siblings like 'company-lookup' or 'taiwan-company-kyb-lookup', which likely have different scopes or geographies.

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 implies when to use the tool (for identity and registration data enrichment) and what inputs are accepted (name, LEI, UK company number). It also explains how to use the optional API key for UK data and notes a cost of $0.01/call. However, it does not explicitly state when not to use it or compare it to siblings like 'company-lookup' or 'litigation-check', leaving room for interpretation.

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