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

Goes well beyond the annotations by disclosing the $0.10 per-call price, the USDC-on-Solana/x402 payment mechanism, the exact retry protocol (call unpaid, read the PaymentRequired challenge, retry with _meta["x402/payment"]), and the HTTP equivalent URL. That is the kind of auth/cost context annotations cannot express; the only gap is that it does not say whether a failed paid call is charged.

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 purpose is front-loaded in the first sentence, with cost and payment mechanics following. The x402 parenthetical is dense but each clause is operationally necessary; no filler sentences.

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?

There is no output schema, yet the description never indicates what an "enriched cross-registry profile" actually returns or how large/complete the payload is. Payment and endpoint details are thorough, but for a data-retrieval tool the agent is left guessing at the response shape.

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 the accepted identifier formats (LEI 20 chars, FR SIREN 9 digits, UK company number 8 chars) are already fully documented in the schema. The description adds nothing about the id parameter, which is acceptable given the baseline but earns no bonus.

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 specific verb and resource ("Fetch an enriched cross-registry company profile") and the word "cross-registry" implicitly separates it from single-registry siblings like companies_uk_company or companies_uk_lei. It does not explicitly name the sibling it replaces, so an agent must infer the boundary against companies_enrich_resolve and companies_enrich_group.

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?

The description explains the payment procedure in detail but never says when to choose this tool over companies_enrich_group, companies_enrich_financials, or companies_enrich_resolve. Usage is implied by the resource name rather than stated as a selection rule.

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