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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered. The description adds genuine value beyond that: results are explicitly indicative, validated only against 'cas de référence Marcel', and it deliberately issues no recommendation, delivering a neutral verdict field instead. It also explains the feasibility caveat (exit withholding exceeding cash, partial ownership, loan capped at available cash with unmodelled financing gap), which is real behavioral context an agent could not infer from 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 purpose is front-loaded, which is good, but the body is one very long run-on sentence and the feasibility parenthetical is dense to the point of being hard to parse. The information is largely load-bearing (there is no output schema), yet restructuring into short labeled clauses would cost nothing and gain clarity.

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?

With no output schema, the description does the right thing by naming the returned figures (costs, cash flows, net per option) and the two verdict fields, and annotations cover the safety profile. However, for a 9-parameter high-complexity simulation it leaves most parameter semantics and the unit/currency conventions unexplained, which is a real gap for correct invocation.

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 only 11% (a single enum description for regimeCedolare), so the description must carry the parameter burden. It only gestures at inputs with 'trésorerie, prix, loyers, horizon', leaving tauxPret, prixRevente, tmiFrance and chargesAnnuelles unaddressed and giving no units, currency or whether rents are gross annual vs monthly. It adds some framing but does not compensate for the coverage gap on a 9-parameter tool.

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 comparison task (two Italian property holding structures from a French SASU) and enumerates the actual mechanisms compared: cedolare secca on private-landlord rents, 5-year capital-gains exemption, and corporate tax on a subsidiary, plus the France-Italy treaty. This clearly separates it from the country siblings (simulate_immo_espagne, simulate_immo_belgique, etc.) and from generic comparison tools like compare_allocation.

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 usage scope is explicit: a property in Italy held from a French SASU, over a given horizon. It never names an alternative tool or an exclusion condition (e.g. 'for a Belgian property use simulate_immo_belgique'), so it stops short of a 5, but the context is unambiguous.

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