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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds valuable context beyond that: it explicitly states 'Résultat ESTIMÉ' (a quality caveat), notes the life-expectancy bound (60–80), and cites legal/source references (CGI art. 158-6, INSEE table). These enrich the behavioral understanding without contradicting 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, dense sentence that front-loads the core purpose and then details the computation steps. Every clause earns its place: it covers inputs, outputs, estimation caveat, and sources without redundancy. The parenthetical source list is compact and useful.

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 read-only estimator with no output schema, the description is complete: it lists all computed outputs (rente brute, part imposable, surcoût d'IR, rente nette mensuelle), states the input scope (age 60–80, capital, fiscal parameters), and flags that results are estimates. It also references the underlying legal/statistical sources, giving an agent confidence in the tool's domain. No critical information is missing.

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%, so the baseline is 3. The description adds meaning beyond the schema by explaining how parameters feed into the calculation: e.g., 'part imposable selon l'âge d'entrée en jouissance' and 'via le cIR de Qotien' clarify the role of revenu_net_imposable and parts. This extra context helps an agent understand the tax logic, though it does not describe formatting or units for any parameter.

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 precise verb ('Estime') and resource ('rente viagère servie contre l'aliénation d'un capital'), and enumerates the computed components (rente brute, part imposable, surcoût d'IR, rente nette). This clearly distinguishes it from fiscal and retraite siblings, which focus on taxes or pension income rather than annuity estimation.

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 provides no guidance on when to use this tool versus alternatives. It does not mention any sibling tools, conditions for use, or exclusions. An agent would have to infer suitability purely from the tool name and description, which is insufficient for correct routing.

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