Vacances, jours fériés et soleil à La Réunion

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered; the description then adds domain-specific behavior beyond that, notably that the calendar is austral and differs from the metropole, that 20 December (Fèt Kaf) is included, and that no output format is described. It does not discuss caching or rate limits, so it is solid rather than exhaustive.

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 lead sentence front-loads the resource and its component data, and the example queries follow as compact routing aids. The trailing English summary duplicates most of the French content and lengthens the block without adding new information, which keeps it from a 5.

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 single optional parameter with no output schema and full annotation coverage, the description supplies enough: the four data categories it returns and the default 'tour de l'île' behavior are stated. The only real gap is the shape of the returned data across those mixed categories, which matters more because no output schema exists.

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% and the single `lieu` parameter is documented in detail there (commune, beach, cirque, summit, or 'lat, lon'; empty = whole island). The description only echoes this by saying sun times are computed at the 'lieu demandé', adding the useful nuance that the place mostly affects sunrise/sunset rather than holidays, but that is a small increment over 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 description names a specific resource and enumerates exactly what it returns: school holidays for the Réunion academy (austral calendar), public holidays including 20 December, today's date, and sunrise/sunset at a given place. That scope clearly separates it from weather siblings like meteo_actuelle, prevision_meteo, or maree, which never return calendar data.

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 provides concrete trigger phrasings (« c'est quand les vacances ? », « prochain jour férié ? », « à quelle heure se lève le soleil au Maïdo ? »), which gives an agent clear context for routing. It stops short of naming exclusions or pointing to alternatives (e.g., use maree for tides, meteo for forecast), so it is strong but not fully explicit about when not to use it.

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