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

Adds meaningful behavioral limitations beyond annotations: profile fields can be null when the public source does not expose them, and the endpoint does not replace specialized endpoints. It also discloses pricing. While readOnlyHint is false, the description does not affirm mutation, so there is no contradiction; it could have been more explicit about auth/rate limits, but it adds substantive context.

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 organized into short labeled sections: 'Use when', 'Avoid when', 'Limitations', and 'Price'. Each segment contributes clear selection or invocation information 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?

For a one-parameter tool with an output schema, the description covers when to use, when to avoid, the identifier type, nullability limitations, and cost. It does not spell out authentication or error behavior, but the explicit routing and limitations make it sufficiently complete for correct selection and invocation.

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 input schema already covers the single parameter with a description and regular expression ('9-digit SIREN or 14-digit SIRET'), and the description repeats 'SIREN or SIRET' without adding additional format details beyond the schema. Since schema coverage is 100%, the baseline 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?

States the exact operation ('Returns the public profile of a French company') and the input key ('SIREN or SIRET'), then enumerates the contained fields (headquarters, activity, legal-form, creation-date, employee-band, establishment-count). This clearly distinguishes it from search, verify, financials, 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?

Contains explicit 'Use when' and 'Avoid when' guidance, routing the agent to company/fr/verify for existence checks and to dedicated endpoints for directors, financials, risk, and compliance. This is exactly the alternative routing an agent needs to select the right tool.

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