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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds that it computes total, average monthly, and first-year cost, which is useful output context, but it does not disclose behavioral traits such as rounding, assumptions about rate application, or limitations. It is consistent with annotations, so no contradiction, but it adds limited behavioral depth beyond annotations.

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 description is a single, efficient sentence that packs the action, the resource, the outputs, and the inputs with zero waste. It is front-loaded with the verb and immediately communicates the core function, making it easy to scan.

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?

The tool is a straightforward calculation with three parameters and no output schema. The description adequately explains the inputs and the expected outputs (total, average monthly, first-year cost), which is sufficient for an agent to invoke it correctly. It lacks details on calculation methodology or edge cases, but these are not critical for basic usage. Overall, it is complete for the tool's simplicity.

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 0%, so the description must compensate. It explicitly names each parameter: capital, taux_annuel_pct (annual rate as a percentage of capital), and duree_annees (duration). It clarifies that the rate is a percentage and the duration is in years, which adds meaning beyond the bare schema types. However, it does not specify the currency for capital, leaving some ambiguity, hence not a 5.

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 clearly states the verb 'Calcule' (calculates) and the resource 'le coût d'une assurance emprunteur' (borrower insurance cost). It also specifies the exact outputs (total, average monthly, first year) and the inputs (capital, annual rate as % of capital, duration). This fully distinguishes it from siblings like 'comparer_delegation_assurance' (which compares delegation insurance) and other unrelated tools, leaving no ambiguity about its purpose.

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 description explains what the tool does but does not explicitly state when to use it versus alternatives. It implies use when a cost calculation is needed, but there is no mention of exclusions, prerequisites, or alternative routing to sibling tools. The context is clear enough for an agent to infer usage, but explicit guidance is lacking.

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