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

With no annotations, the description carries full behavioral disclosure. It discloses that it returns three specific pieces of information (legal existence, admin status, insolvency flag), implying a read-only operation. It also adds the pricing model ('$0.030002/call, paid per request via x402') which is useful behavioral context. However, it doesn't explicitly state that it won't modify anything or clarify the absence of an output schema, but given the read-only nature implied by 'check', it's reasonably transparent.

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 concise and well-structured: it opens with the purpose, then the scoping ('The minimum...'), then the upgrade path, then pricing. Every sentence adds value and there is no fluff. It is front-loaded with the most important information.

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 tool with one simple parameter and no output schema, the description covers the purpose, usage, and pricing, but misses the essential definition of the 'q' parameter. This is a significant omission because an agent cannot correctly invoke the tool without knowing what to supply. It is otherwise fairly complete for the minimal scope, but that missing parameter explanation brings it down.

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?

The schema has a single required parameter 'q' with no description, and schema description coverage is 0%. The description does not explain what to pass in 'q' — it doesn't mention that it should be a company name, SIREN, or registration number. Since the description is the only source of parameter meaning, this is a critical gap. It fails to compensate for the schema's lack of parameter documentation.

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 verb ('Lite know-your-business check'), a specific resource ('a French company'), and enumerates the scope ('legal existence, current administrative status and any insolvency flag'). It also differentiates from the full sibling by calling itself 'Lite' and explicitly naming the upgrade path to /v1/fr/kyb, so an agent can tell it apart from fr_kyb and other sibling tools.

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 provides explicit usage guidance: 'The minimum an agent needs to decide whether a counterparty is real and active before going further' and 'Upgrade to /v1/fr/kyb for directors, beneficial owners and the full compliance dossier.' This tells the agent exactly when to use this tool versus the full version, and includes the pricing detail per call.

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