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

Annotations cover the safety profile (readOnly, openWorld, not idempotent), so the bar is lower; the description adds real context beyond them: the data is 'live', coverage depends on UK Companies House being 'enabled', and it is priced at $0.03 per call via x402/prepaid credits. It does not mention rate limits or freshness/latency, keeping it short of 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?

Content is front-loaded: what it returns, then scope, then the alternative tool, then pricing. Dense but each sentence earns its place; the pricing/trial sentences are useful for an agent that must consider cost.

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?

An output schema exists, so return values need not be described, and the annotations carry the safety profile. For a 2-parameter, read-only enrichment tool the description is nearly complete; only the sibling boundary with company-techstack is left slightly ambiguous.

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 description coverage is 100%, so both parameters (name, domain) are already documented with formats and purpose. The description adds no additional syntax or constraints beyond the schema, which is the expected baseline when the schema does the heavy lifting.

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?

Names a specific resource (live company profile from a domain) and enumerates its concrete contents: techstack, domain age/registrar, security headers, LEI register entities, and UK Companies House matches. It explicitly distinguishes itself from /company/report, so an agent can route without opening either 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?

Gives clear context (companies only, no personal data) and names an alternative ('For an AI-written report with news use /company/report'). It does not, however, clarify the boundary against the closely-named sibling company-techstack even though it says this tool is a superset of it.

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