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

With no annotations, the description carries the full burden. It discloses the key behavior that the server resolves INSEE values automatically, which adds value. However, it does not describe side effects, response format, error handling, or any prerequisites beyond inputs. For a simulation tool this is acceptable but incomplete.

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 two sentences, front-loaded with the core behavior and usage, and ends with a brief French label. Every sentence earns its place, with no redundant elaboration. The brevity aids quick scanning.

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 simulation tool with 5 well-described parameters and no output schema, the description covers the key context: what it does differently, what inputs to provide, and when to prefer it. It lacks return-value details, but the reference to 'simulate_irl' and the simulation nature make this acceptable for selection and 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 coverage is 100%, so the baseline is 3. The description only restates the parameters as 'the rent, the two quarters and the region' without adding format details, relationships, or examples. It does not clarify old vs. new quarters beyond what the schema already provides.

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 tool simulates a rent revision (loyer) using automatic INSEE IRL values, and explicitly distinguishes it from the sibling 'simulate_irl' by noting the server resolves official values itself. The verb 'simulate' and resource 'revision de loyer IRL' are specific, and the contrast with the sibling clarifies its unique scope.

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 gives an explicit usage trigger: 'Prefer this when you don't know the exact IRL values.' It also contrasts with 'simulate_irl' ('Like simulate_irl, but...'), helping the agent choose between the two. This provides clear when-to-use guidance and an alternative.

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