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

Annotations already state readOnlyHint=true and openWorldHint=false, covering safety. The description adds substantial behavioral context: deterministic rules, legal references (loi n° 2021-1104, loi n° 89-462 art. 17-1), exact threshold dates for bans and rent freezes, and that no AI is involved. It does not mention rate limits or side effects, but for a pure lookup this is strong added value.

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 English purpose statement is front-loaded and followed by legal detail that earns its place for a compliance-oriented tool. The bilingual header partially duplicates the title, adding some redundancy, but the overall structure is efficient and not bloated.

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 two-parameter deterministic lookup with no output schema, the description explains exactly what is returned (letting ban status and date, rent freeze, DPE validity) and the condition under which validity is checked. With annotations covering read-only and closed-world behavior, nothing essential 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% and both parameters are documented in the schema itself. The description reinforces meaning (DPE class A–G, dpe_issue_date enabling validity) but adds no syntax, format, or constraint beyond what the schema already provides, so the 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?

Names a specific resource ('French rental restrictions') and action ('returns') tied to a DPE class. The domain is clearly distinct from sibling calculators like calculate_rent_revision or calculate_tenant_notice_period, though it does not explicitly name or differentiate against those siblings.

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 by 'Given a dwelling's DPE class (A–G), returns...' and the conditional mention that dpe_issue_date enables the validity check. However, there is no explicit when-to-use, when-not-to-use, or alternative-tool guidance, leaving routing to inference.

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