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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needs to add context beyond that. It does add that the result is a rough estimate derived from cadastral value and a commune rate, which is meaningful, but it says nothing about precision limits or assumptions.

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?

Two tight sentences with the core purpose front-loaded and no filler. The trailing list_bundles pointer is slightly off-topic for the stated action but still earns some place as a routing aid.

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?

With a full output schema and comprehensive annotations, the description need not explain return values or safety behavior, and it correctly avoids doing so. The one real omission is disambiguation from calculate_property_tax_fr and guidance on sourcing the cadastral value.

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% (commune_rate in percent, cadastral_value as valeur locative cadastrale EUR), and the bounds/ranges are in the schema. The description names the same two inputs but adds no unit, range, or format meaning beyond them, so baseline 3 applies.

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 and resource ('Estimate French taxe foncière') and names the two inputs that scope it, which separates it from the many other tax calculators. It does not, however, distinguish itself from the very similarly named sibling calculate_property_tax_fr, leaving an ambiguity an agent must resolve on its own.

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?

There is no statement of when to use this tool versus alternatives, nor prerequisites (e.g., that cadastral value is the valeur locative cadastrale, not market value). The only pointer, 'See list_bundles for related immobilier calculators', is a discovery hint rather than usage guidance.

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