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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuine behavioral content beyond them: absent values are returned as null and surfaced in a 'missing' list and are never estimated, plus each item carries its sources and survey date. It does not cover failure behavior (invalid id, mismatched types), which keeps it at 4.

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?

Front-loaded with the verb and the 2–5 scope, and every clause earns its place (type enumeration, missing-value rule, no-ranking constraint, citation requirement). It is a single very dense sentence with stacked parentheticals, so structure could be improved with lighter segmentation.

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 only one parameter, a rich annotation set and no output schema, the description does the work the missing output schema would otherwise do: it describes the comparison axis (attribute by attribute), the shape of gaps (null plus missing list), and per-item provenance with dates. An agent has everything needed to call it and to interpret the response.

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 0%, so the description must carry the load: it explains that the ids must all belong to the same comparable type and enumerates the four valid prefixes, which gives meaning to the regex pattern that the schema alone cannot convey. It also restates the 2–5 arity bound, which the schema already has via minItems/maxItems, but the type-prefix semantics are real added value.

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 (compare), a bounded resource (2 to 5 items of the same comparable type), and enumerates the valid type prefixes (model, crypto_platform, cloud_provider, cloud_offer). An agent can immediately tell this apart from search_content or get_content, which retrieve rather than compare.

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?

Usage is clear: compare homogeneous items attribute by attribute, with the explicit pre-step 'Trouver les identifiants avec search_content' routing the agent to the sibling that produces the required ids. It also rules out ranking/scoring use cases ('Aucun score ni classement'). No explicit 'do not use for X, use Y instead' alternatives beyond that, so it stops short of a 5.

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