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

The description adds useful behavioral details such as cited sources, exclusion of personal contacts, and x402 payment retry mechanics. However, it explicitly says sources include the company homepage, Wikidata, and SEC EDGAR, which are external open-world sources, while the annotation declares openWorldHint=false. That is a direct contradiction.

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 front-loaded with the purpose and return fields, then moves to sources, exclusions, cost, and payment handling. It is dense but mostly earns its space because payment behavior is non-obvious and materially affects invocation. Minor wording like 'POST a company domain' is slightly awkward but does not obscure meaning.

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 no-output-schema tool with payment requirements and multiple source toggles, the description does a good job listing returned fields, source types, exclusions, and payment retry behavior. It could be more complete by clarifying that at least one of domain or ticker is required, since the schema marks zero required parameters. The main completeness gap is lack of sibling differentiation, not missing invocation-critical information.

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 all five input parameters are already documented in the schema. The description adds only that a domain or ticker should be supplied and explains the payment fallback outside the normal schema parameters. Since the schema already carries the parameter semantics, the baseline score of 3 is appropriate.

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 states a specific resource and verb-like action: submit a company domain or ticker and receive cited firmographics, with a concrete list of returned fields. It is clear what the tool does, but it does not explicitly distinguish itself from sibling tools such as company_dossier, company_filings, or company_legal_identifier.

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?

Usage is implied by the description: use this tool when you need company firmographics from a domain or ticker. However, it gives no explicit when-to-use versus when-not-to-use guidance and does not point to alternatives among the many company-related sibling tools. Payment retry guidance is present, but that is invocation guidance rather than tool-selection guidance.

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