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

Annotations already cover the safety profile (readOnly, openWorld, idempotent, non-destructive), so the description doesn't need to repeat that. It adds useful behavioral context beyond annotations: the search is exact, only the number is transmitted to the official API, and the result confirms a published identity rather than financial or website-ownership facts.

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 short sentences communicate the operation, the transmission boundary, and the output's limits without filler. The core action is front-loaded, and each sentence earns its place by adding a distinct fact an agent needs.

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 simple two-parameter read-only lookup with an output schema and strong annotations, the description is nearly complete: it specifies input format, exact-match behavior, official source, and what the result does not certify. The only notable gap is the undocumented role of as_of, which is minor given the schema title and the tool's scope.

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 description coverage is 0%, so the description must compensate. It meaningfully clarifies the identifier parameter by specifying SIREN or SIRET and exact matching. However, the optional as_of parameter is never mentioned, leaving its historical-reference semantics to be inferred solely from the schema title and type.

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 opens with 'Recherche exacte d'un SIREN ou SIRET dans l'API Recherche d'entreprises', naming a specific verb, resource, and input type. It clearly distinguishes this identity-verification lookup from the sibling routing, scoring, and lookup tools by scoping it to exact matches against an official administrative registry.

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 implies use when an agent needs to verify a published administrative identity via exact SIREN/SIRET lookup. It also gives explicit exclusions: the result never establishes reliability, solvency, or website ownership, which prevents the agent from misusing the tool for those judgments. It does not name sibling alternatives, but the boundary it draws is enough to guide selection.

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