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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint and destructiveHint, so the safety profile needs no repetition. The description usefully discloses what is actually returned (resolved records, provider, tech stack, RDAP dates, subdomains), which annotations do not cover. However, it never mentions the masked-vs-unmasked output behavior or rate/credit costs that the schema's payment parameters imply, which is material behavior for this tool.

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?

Two sentences, front-loaded with the domain-scope summary followed by a compact capability list. Every clause earns its place by naming a distinct output. Slightly list-heavy but with no filler.

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 return-value burden and does so by enumerating the five result categories. Combined with annotations covering the safety profile and fully documented parameters, an agent has what it needs to call it correctly; only the paywall/masking behavior is left to the schema fields.

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 the domain, x_api_key, and payment_signature parameters are already documented with examples and the 'unmasked dataset' semantics. The description adds no parameter-level detail beyond that, 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 a specific resource (B2B company & domain infrastructure) and enumerates concrete operations: DNS records (A, MX, TXT, NS), email provider identification, SaaS tech-stack detection, RDAP registration dates, and subdomain discovery. That is well beyond a restatement of the name and separates it from siblings like security_audit or b2b_company_dossier. It stops short of explicitly distinguishing itself from those overlapping siblings (e.g., b2b_company_dossier).

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?

There is no when-to-use or when-not-to-use guidance, no prerequisites, and no mention of alternative tools. The agent is left to infer that this is the DNS/infrastructure recon tool and that b2b_company_dossier or security_audit cover adjacent needs. Nothing routes the agent between this tool and the sibling that unlocks unmasked results.

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