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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description builds on that by adding key constraints: max 12 trimestres, abattement ≤40 for études, stage at 12% PMSS, and the two option modes. It clarifies the deductibility and ROI calculation. It doesn't contradict the annotations and provides useful behavioral context beyond the structured hints.

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 dense paragraph, but it is well-organized: it starts with the main purpose, then details the computation basis, options, legal limits, and sources. Every sentence carries meaningful information. Though lengthy, the complexity of the domain justifies the size, and it is front-loaded with the core purpose.

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?

Without an output schema, the description names the key outputs (coût, gain, ROI) and covers legal thresholds and sources. It does not specify the exact response structure but gives enough for an agent to know what to expect. Combined with the schema-validated parameters, it is reasonably complete for a tool of this complexity.

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 description adds critical parameter context: it explicitly warns that tmi must be a fraction (0-1) and not a percentage (contrasting with the sibling tool fiscal_tmi), explains the two option values, and states the legal maximum trimestres. This goes beyond the schema's terse descriptions and helps the agent avoid common pitfalls.

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 identifies the tool's purpose: computing the cost and profitability of buying retirement quarters (rachat de trimestres). It specifies the legal article (L351-14-1), names the two options (taux seul / taux et durée), and the outputs (coût, gain, ROI). It distinguishes itself from sibling tools like retraite_estimation or retraite_optimisation by focusing on the buyback scenario, making it unambiguous what this tool does.

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 implies usage for rachat de trimestres (buyback) but does not explicitly state when to prefer this tool over alternatives such as retraite_estimation or retraite_optimisation. It describes the domain and constraints but lacks explicit 'use this when' or 'use alternative X when' guidance, leaving the agent to infer based on the topic.

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