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

Beyond the readOnlyHint annotation, the description discloses deterministic behavior ('Deterministic INSEE data + fixed formula — no AI'), the legal basis (loi n° 89-462 art. 17-1), and specific enforced limits (one-year forfeiture, DPE F/G freeze since 25 August 2022). This provides substantial operational transparency that annotations alone would not convey.

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 front-loaded with a concise bilingual summary, then delivers the formula, legal limits, parameter guidance, and determinism note in a structured sequence. Every sentence carries necessary information with no filler — it is long but dense and well-organized.

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?

Given the tool's complexity (legal formula, multiple constraints, data source), the description covers all essential aspects: inputs, formula, legal limits, DPE freeze, geographic scope, and deterministic nature. No output schema exists, but the output is clearly implied as the new rent amount in euros. This is complete for an agent to select and invoke correctly.

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 baseline is 3. The description adds meaningful context: it explains that reference_quarter comes from the lease, that dpe_class triggers the freeze check, and clarifies that current_rent is 'hors charges'. These clarifications reinforce the schema's descriptions and add legal purpose, but they don't add new syntax or format details 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 'Computes the legally revised rent for a French residential lease using the INSEE IRL' with the exact formula. It distinguishes itself from sibling tools (e.g., Swiss salary calculator, DPE restriction checker) by specifying the French rent revision context and the specific legal calculation.

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 clear context for when to use the tool: for computing legally revised rent under French law, with special handling for the one-year claim limit and DPE F/G freeze. It explains when to pass dpe_class for the freeze check. However, it doesn't explicitly name alternative tools or state when not to use it, so it stops short of full when/when-not guidance.

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