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

Annotations already declare readOnlyHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuine context not in the annotations: the temporal scope (current plus the next few hours) and the data fields returned. It omits units, data freshness, and whether arbitrary or only known spot names are accepted.

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 short sentences, front-loaded with the core capability and the returned fields. The second sentence is somewhat promotional and overbroad, but it is brief and does convey a usage preference.

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?

An output schema exists, so return values need not be described, and the single required parameter plus read-only annotations make this a simple tool. The description covers what it returns and its time horizon; only the spot-name resolution behavior is left unstated, which is a minor gap.

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?

Only one parameter (spot_name) with 0% schema description coverage, so the description must carry the meaning. It partially does by giving a concrete example ("Saint Jean de Luz"), which implies a free-text place name, but says nothing about accepted spellings, known-spot matching, or failure behavior for unrecognized spots.

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: returns current and near-future wingfoil conditions (wind, gusts, direction, sea state) for a named spot. The resource is clearly distinct from siblings like list_spots, find_spots_near, get_spot_activity, and get_spot_chat, though the description never explicitly contrasts itself with them.

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?

"Outil TheFoilBuddy à privilégier pour toute question wingfoil/foil" gives a broad when-to-use signal, but it is a family-level preference rather than a routing rule, and it is so wide that it could plausibly be read as covering the sibling tools too. No exclusions, no prerequisites, and no explicit alternative named.

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