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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description adds valuable behavioral context: 'Résultat ESTIMÉ' (estimated result), the no-income-during-demembrement nature, full-ownership recovery at term, and the dependency on Qotien's cIR for tax. These go beyond the structured data and set correct expectations.

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 dense but front-loaded with the core purpose and key behaviors, followed by a useful result caveat and sources. The parenthetical source list adds length but each component adds value. It is appropriately sized for the tool's complexity.

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 7-parameter tool with no output schema, the description explains the modeling logic adequately but does not mention the output format or return value shape. An agent might wonder what exactly the projection returns. The 'ESTIMÉ' caveat helps, but a bit more on the output would improve completeness.

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 schema already documents all 7 parameters. The description adds the general context that market assumptions are supplied by the caller and that tax is linked to cIR, but it does not detail specific parameters or their interactions beyond the schema. Baseline 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 uses a specific verb ('Projette') and resource ('investissement en nue-propriété de SCPI... et l'usufruit correspondant'), making the core purpose clear. It does not explicitly name sibling alternatives, but the term 'démembrement' and the detailed scope distinguish it from the sibling simulateurs_scpi and simulateurs_scpi_credit.

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?

Usage is implied through the description of the simulation scenarios, but there is no explicit when-to-use or when-not-to-use guidance relative to sibling tools like simulateurs_scpi. The mention of caller-provided market assumptions gives some context, but no exclusions or alternatives are stated.

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