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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds meaningful context beyond annotations by stating the list contains 60 free calculators and exposes their slug identifiers.

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?

The definition is one front-loaded sentence with no wasted clauses. The count, 'gratuits', category examples, and slug mention all add useful information for selecting and interpreting the tool.

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 read-only list tool with one fully documented optional parameter and no output schema, the description provides enough context to call it correctly. A brief note on using get_calculator for individual records would make it complete.

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?

The single optional 'group' parameter is fully documented in the schema, including the available group names, so schema coverage is 100%. The description does not mention filtering by group, but with full schema coverage the baseline score of 3 is appropriate.

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 names a specific verb ('Liste') and resource ('calculateurs et simulateurs'), and adds useful scope: 60 free tools, example categories, and the returned slug identifier. It is clearly distinguishable from get_calculator, which by name suggests retrieving one calculator rather than listing all.

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 listing purpose implies when to use it, but there is no explicit guidance such as when to choose this over get_calculator, compute_calculator, or search_services. Usage is inferable from the description rather than stated.

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