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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds that the output also includes features common to all plans and cites a source URL, but says nothing about return format beyond what the output schema provides. Adequate, not rich.

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?

A single dense paragraph that front-loads what the tool produces, then usage, then the parameter, then exclusions and source. No wasted sentences, though it packs several concerns into one block.

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?

An output schema exists, so return-value explanation is unnecessary. The description covers scope, compared fields, an example query, an exclusion, and the data source, leaving little an agent would need to add.

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%, and the schema already documents plan_ids with enum values and a 'tous par défaut' default. The description restates that it is optional and covers two or three plans, adding only marginal meaning over the schema.

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 artifact (comparison table) for a specific resource (Comontel plans) and enumerates the compared dimensions (prix, Go en France/Europe, 5G, réseau) plus the common features. This clearly distinguishes it from siblings like get_plan (single), get_plans (list), and recommend_plan.

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?

Gives an explicit trigger phrase (« quelle différence entre Essentiel, Pro et Business ? ») and a clear exclusion ('Ne compare pas avec d’autres opérateurs'). It does not name alternative sibling tools by name, but the when-to-use context is unambiguous.

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