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

Annotations already declare readOnly/idempotent/non-destructive/non-openWorld, and the description adds substantial context beyond them: rate limits (30/min, 1000/day per IP shared with the HTTP endpoint), per-source CC BY 4.0 attribution, a disclaimer, the historical status of the 2017-2019 ZIS, and the March 1, 2026 new-generation map gap. This is exactly the extra context annotations cannot carry.

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 English text is well front-loaded ("FREE, no API key") and every English sentence carries caveats that matter. However, the full French translation roughly doubles the length without adding information an agent can act on, which is padding in a single tool description.

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?

Despite having no output schema, the description enumerates the return payload (zones at the point, source zone type, distance to nearest zone, attribution, disclaimer) and flags the limits and data vintage. Nothing an agent needs to call this correctly or interpret the result is missing.

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 100% schema coverage the baseline is 3; the description earns more by stating the mutual-exclusivity constraint (exactly one of lat+lon, address, lot) that the schema, which has zero required params and no oneOf, cannot express, and by noting address is matched to the Référentiel québécois des adresses and lot to RQA address points. Only lang is left solely to the schema.

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 ("Checks which of 9 open Québec flood-zone sources ... intersect a point") and enumerates the sources by name. It is unmistakably distinct from every sibling (lot_get, lot_resolve, plan_get), none of which deal with intersect queries.

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?

Gives an explicit input contract ("Give exactly one of: lat+lon, address ... or lot") plus clear when-not-to-trust guidance: a no-hit never means the property is outside a flood zone, the lot boundary is not evaluated, and answers must be confirmed on the official Québec map because new-generation maps are excluded.

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