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

Beyond the readOnlyHint/openWorldHint annotations, it discloses the paid nature ($0.99 USDC per call), the exact failure-then-retry payment flow, the free-webmail filtering behavior, and a deployment exclusion (China MCP). These are meaningful traits an agent cannot derive from structured fields, though rate limits and per-call failure modes beyond payment are unstated.

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?

Front-loaded with the highest-value facts (paid call, 20 domains, what data comes back), then payment mechanics. Dense but nearly every clause carries information; the only soft spot is the ambiguous 'Excluded from China MCP' fragment, which lacks enough context to be actionable.

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?

With no output schema, the description carries the burden of describing returns and does so at a summary level (contacts, emails/phones, socials, firmographics), which is sufficient for selection. For a paid, authorization-gated network tool, it covers cost, consent, and payment recovery; only response shape granularity and rate limits are missing.

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 all three parameters are already documented, including the 1-20 domain bound and the soft-match on industry. The description restates the 20-domain cap and the keyword matching but adds no new format or syntax meaning, so the baseline 3 applies.

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 names the resource (company domains, up to 20) and enumerates exactly what is returned: public business contact pages, company emails/phones, socials and light firmographics. It is clearly a bulk domain-to-lead enrichment tool, distinguishable from single-contact siblings like extract_contacts, though it never names an alternative explicitly.

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?

It gives practical invocation guidance for the payment handshake (first call returns x402 requirements, retry with X-PAYMENT/PAYMENT-SIGNATURE or params._meta["x402/payment"]) and states the authorized-collection precondition. However, it offers no guidance on when to pick this over company_dossier, company_facts, or extract_contacts, so alternative selection is left entirely to inference.

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