Acheter ou louer ? / Rent vs buy in a city

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

No annotations are provided, so the description carries the full burden. It thoroughly discloses data sources (CMHC, Bank of Canada), assumptions (20% down, 25-year amortization, etc.), and return values (cash outlay vs economic cost). There is no contradiction with annotations.

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 a single, front-loaded paragraph of four sentences. It efficiently conveys the tool's purpose, inputs, assumptions, and outputs without unnecessary words.

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 single parameter and no output schema, the description fully covers what the agent needs: when to use, what data is used, assumptions, and what the tool returns. It also addresses the limitation about CMHC coverage.

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% for the single parameter 'ville', and the schema provides a basic example. The tool description does not add additional semantics beyond what the schema already provides, so it earns the baseline score of 3.

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 explicitly states that the tool compares renting vs buying in a Canadian city, using specific metrics (average rent and carrying cost). It uniquely addresses the rent vs buy question, distinguishing it from sibling tools like taux_courants or contacter_expert.

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 clearly states when to call the tool ('when the user wonders whether to rent or buy in a Canadian city') and notes a limitation ('Only cities inside a CMHC-covered metro have rent data'). It implies when not to use (if city is not covered), but does not provide explicit alternatives.

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