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

Beyond the read-only/idempotent annotations, it discloses important behavioral caveats: the winner stays null until all acquisition costs are confirmed, knownCostWinner is conditional on currently known costs, and the result is a scenario rather than a verdict. It also notes that the tool returns a prefilled website link, which is useful context not covered by the 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 dense and front-loaded with the core purpose before caveats and output behavior. The sentence about winner and knownCostWinner is somewhat jargon-heavy, but every part carries useful information.

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 complex 8-parameter simulation tool with an output schema, the description supplies the essential framing, caveats, and result-link behavior. Remaining gaps are minor, such as not clarifying the commune parameter's role or when to prefer this over adjacent calculators.

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?

With only 50% schema description coverage, the description meaningfully compensates by naming most inputs and clarifying that rent must be comparable and mortgage rate is an explicit assumption. It covers down payment, loan term, horizon, and property tax, though it does not explain the commune parameter or add units where the schema lacks descriptions.

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 names a specific comparison (buying vs renting the same Luxembourg home over time) and the key inputs that drive it. It is clearly distinguishable from siblings like calculate_mortgage or analyze_lease, which cover narrower pieces rather than the full buy-vs-rent comparison.

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?

It explains that the tool works from explicit assumptions and uses the website simulator, which tells the agent when this tool is appropriate. It does not explicitly name alternatives or state when not to use it, so it falls short of full routing guidance.

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