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

Annotations provide readOnlyHint=true and openWorldHint=false, but the description adds crucial context beyond this: it specifies the return contents, the 24-month DVF window, the cost of 10 credits per call, and important methodological caveats (excludes certain costs, rent type). This goes well beyond the structured fields.

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?

Well-structured with required/optional sections, clear bullet points, and a short cost note. However, the description is somewhat verbose and could be slightly more front-loaded with the core purpose before diving into details.

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 lack of an output schema, the description compensates by detailing the return values (latest 24-month DVF window, median sale price/m², ANIL rent/m², estimated gross yield, confidence interval, data-quality flags). It also covers scope limitations and cost. Complete for an agent to 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 the schema already documents parameters. The description adds value by explaining the INSEE code format and examples, clarifying that appartement_profile applies only to apartments, and specifying defaults and enum meanings.

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?

States a specific verb (Estimate) and resource (gross rental yield) with explicit data sources (ANIL asking-rent indicators, DVF sale prices). Clearly distinguishable from siblings like estimate_property_value or analyze_market_statistics.

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?

Explicitly frames the scope as commune-level and lists what it excludes (taxes, financing, vacancy, maintenance, management), guiding the agent away from misuse. However, it does not explicitly name alternative sibling tools that might be more appropriate for property-specific valuation.

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