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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds non-obvious behavior beyond them: the 10-credit cost, the null-on-insufficient-data rule, and what the score actually encodes. Return format is conveyed via an example rather than a schema, so remaining gaps are minor.

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?

Front-loaded with the purpose and scoring logic, then required/optional params, then example, caveat, and cost. Every block earns its place, though the example output plus the duplicate 'Note' line adds some length.

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?

No output schema exists, yet the description supplies an example return object with all fields, their meaning, the score encoding, the insufficient-data edge case, and the cost. An agent has everything needed to invoke and interpret this tool 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 baseline is 3. The description does add one thing the schema cannot show: because required is empty in the schema, its 'REQUIRED: at least one location' and 'OPTIONAL: type_local' labeling supplies the real constraint. That is a modest but genuine addition on top of fully documented parameters.

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+resource ('Identify renovation opportunities') and pins the cohort precisely: 'pre-1975 buildings priced below the area median.' The score range and its drivers (discount + older stock) make it distinguishable from siblings like analyze_building_age_price_impact or detect_flips without opening a schema.

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?

Specifies the location requirement ('at least one of code_postal, commune, or code_departement') and the optional type_local filter, plus the reliability guard (<10 transactions → null). It does not name a competing sibling or state when this is preferred over analysis tools that also look at age/price, so it stops short of explicit routing.

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