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

Beyond the readOnlyHint and openWorldHint annotations, the description usefully discloses that the tool is FREE, uses deterministic pattern matching, performs Luhn/checksum validation, returns recommended calls with prices, and never stores or logs the text. These are meaningful behavioral traits that help an agent infer cost, privacy, and reliability expectations.

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?

Three tight sentences with no wasted words. The 'FREE' hook is front-loaded, the core detection scope follows immediately, and the behavioral caveats (deterministic, no logging) are compressed into one succinct closing sentence.

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?

With a single required parameter, an output schema present, and annotations covering read-only/open-world behavior, the description supplies everything needed for correct invocation. It covers what to feed it, what it detects, what it returns, when to use it, and privacy/cost implications. No meaningful gap remains.

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 baseline is 3. The description adds practical input semantics by specifying acceptable text sources ('email, invoice, contract, web page'), which helps the agent decide what to pass in the 'texte' parameter beyond the schema's raw type/length constraints.

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 names a specific verb ('detect'), a concrete resource ('French/EU company identifiers'), and enumerates the exact identifier types (SIREN, SIRET, EU VAT, LEI). It also distinguishes itself from the sibling tools by adding that it returns the recommended Sirenic call and price, making its role as a detection/triage tool unmistakable.

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 gives clear usage context: 'Use this FIRST whenever a company appears in your workflow' and lists concrete scenarios (supplier onboarding, payment, due diligence). It does not explicitly name when not to use it or contrast with specific alternatives, but the priority instruction provides strong guidance.

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