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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the deprecation lifecycle context and compatibility-only constraint, which is meaningful beyond the annotations, though it does not add rate-limit or auth details.

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, both earning their place, with the deprecation warning and replacement tool front-loaded before the compatibility condition. There is no redundant or filler text.

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 single-parameter, read-only compatibility tool with no output schema, the description covers lifecycle status, intended use, and the alternative tool. Annotations supply the safety profile, so nothing an agent needs to call it correctly is missing.

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 100%, so the single `identifier` parameter is already fully documented as a 9-digit SIREN or 14-digit SIRET. The description mentions SIREN/SIRET but adds no format or syntax detail beyond the schema, matching the baseline 3 when the schema does the heavy lifting.

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 (lookup) and resource (legacy flat French company by SIREN/SIRET), and explicitly names the sibling `factrail_verify` as the preferred alternative. An agent can distinguish this deprecated compatibility shim from the modern verification 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?

It gives explicit when-to-use guidance: only when an older integration still expects the legacy flat lookup, and it names `factrail_verify` as the replacement. It also states it is kept callable for compatibility only, which tells the agent not to select it for new work.

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