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

Beyond the annotations, the description discloses non-obvious behavior: it aggregates official/public sources, returns normalized identity/legal/address/NACE-ATECO data, and requires an x402 payment of 0.05 USDC on Base Mainnet per call over Streamable HTTP. These cost, source, and transport details are exactly what an agent cannot infer from schema or annotations. No contradiction with readOnly, idempotent, or open-world hints.

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 packs purpose, sources, inputs, returns, use cases, transport, and pricing into six concise sentences, leading with the core function. It is longer than minimal but every sentence carries distinct information, and the payment/transport details are logically placed at the end.

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 single-parameter, read-only lookup with no output schema, the description is complete: it covers accepted identifier forms, source behavior, returned fields, intended use cases, transport, and cost. An agent can decide when to call it and what to expect from the response. Error behavior is not described but is not essential given the read-only, open-world, idempotent semantics.

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% and the schema already fully explains the identifier parameter as Codice Fiscale, Partita IVA (optionally prefixed with IT), or 20-character LEI. The description repeats these options but adds no parameter-specific meaning beyond the schema. Baseline 3 is appropriate because the structured schema does the heavy lifting.

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 leads with a specific verb and resource: 'Italian company registry lookup, verification and KYB pre-check' using named official sources. It enumerates accepted identifiers and output categories, so an agent can tell exactly what the tool does. No sibling tools exist, so sibling differentiation is not 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?

The description states concrete use cases: supplier verification, procurement, due diligence, and compliance. It does not provide when-not-to-use guidance because there are no sibling tools or obvious alternatives. For a singleton lookup tool, this is actionable context.

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