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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds a real behavioral detail the annotations do not: the result is capped at 10 companies and includes only the SIREN, signalling this is a thin discovery call rather than a full retrieval.

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?

Two sentences with no filler; the primary capability comes first and the follow-up routing is compressed into a short closing clause. Every clause carries 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?

With no output schema, the description must convey return behavior, and it does state the 10-result cap and the SIREN field. It omits pagination or narrowing advice when results hit the cap, which is the main remaining gap for a search tool.

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 50%, with department and postal_code undocumented in the schema. The description compensates by giving concrete department formats ('75, 2A, 971') and a NAF example ('10.71C'), which clarifies two of the four parameters beyond what the schema's patterns show on their own.

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 a specific verb and resource ('Finds French companies') plus the narrowing dimensions (department, postal code, NAF activity code). It also names the sibling get_company as the follow-up, so an agent can distinguish this search tool from the profile-fetching tool without opening either schema.

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?

Explicitly frames this as a lookup step and routes the agent forward ('Use get_company next for the full profile'), which is genuine usage guidance. It stops short of stating when *not* to use it or how it differs from siblings like get_establishment or validate_identifier.

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