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

With no annotations, the description carries the full burden and does well: it discloses the $0.01 USDC cost, that the response is x402 payment requirements rather than the lead itself, and that the caller's wallet must execute the payment. That is non-obvious, high-value behavioral context. It stops short of describing failure modes (e.g. no email found, invalid domain) or whether the payment is charged on a miss.

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?

Roughly four short sentences, front-loaded with the resource and the payload/cost, and the examples sit at the end where they are easy to copy. The opening 'people search: company enrichment' fragment is the only slightly noisy bit and could be tightened.

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 one-parameter paid lookup with an output schema, the description covers the essential non-schema facts: what is returned (verified email + source URL), the cost, and the payment handshake. Return-value detail is correctly left to the output schema. Missing only edge-case behavior for lookups that yield no email.

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 0% for the single 'query' parameter, so the description must compensate. The two worked examples (query="Acme Corp", query="acme.com") do communicate that both a company name and a domain are accepted, which is the key semantic the schema omits. It does not say whether a person's name or email is also valid, leaving a small gap.

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?

States a concrete verb+resource (lookup/enrich a lead, returning a verified business email and source URL), and the two example queries make the resource unambiguous. The lead-in phrase 'people search: company enrichment by company name or domain' slightly muddles whether it is people or company search, but the rest of the sentence resolves it. Siblings are in different domains (dns, ssl_check, headers), so no direct disambiguation is needed.

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?

No statement of when to use this versus alternatives, and no prerequisites beyond the implicit query. The two examples (company name vs domain) hint at acceptable input forms but do not constitute usage guidance. Nothing tells the agent when this tool is the wrong choice.

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