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

Annotations already declare readOnly, idempotent and closed-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: nearest-field results are capped at 5, the radius is 500 m, and ambiguous postal codes return an 'options' envelope instead of failing. The licensing line ('usage non commercial', CC BY-NC 4.0) is a real usage constraint, but no error/permission or empty-result behavior is described.

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 first two sentences are dense, front-loaded and every clause earns its place. The closing provenance block, however, lists BNVD 2024, the Rigal & Perrot index and SISE-Eaux tap-water data — sources unrelated to this tool's outputs — which is padding that competes for the agent's attention.

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?

There is no output schema, and the description compensates by enumerating the returned fields (distance, direction, crop, 500 m parcel count, area, organic parcels, dominant crops with readable labels) plus the 'options' response shape. Missing only failure behavior: what happens with no identifier, an unknown INSEE code, or a commune with no schools.

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 coverage is 100%, so the baseline is 3; the description goes beyond it by stating the mutual exclusivity of insee/code_postal/slug (one identifier only), a constraint the schema itself does not express. It also frames school as a name filter matching on substring, consistent with 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?

The first sentence names a precise resource (school ↔ agricultural parcel proximity for a commune) and enumerates the returned measures: nearest-field distance, direction, crop, count of parcels within 500 m, area, organic RPG parcels, dominant crops. The resource is unmistakable, though the phrasing is nominal ('Détail de…') rather than an explicit verb, and no sibling is named to sharpen the boundary.

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 gives a real operational rule: exactly one of insee, code_postal or slug must be supplied, and a shared postal code returns an 'options' field listing candidate communes — that is exactly the decision an agent needs before calling. The school filter is also flagged as optional narrowing. It stops short of stating when-not-to-use or pointing to an alternative tool (e.g. search_communes for resolving identifiers).

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