Crues et rivières à La Réunion

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful context: 5-minute measurement cadence, 29 station coverage, per-river granularity, and that historical floods are included as reference points. It stops there, omitting anything about response shape or failure modes.

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?

Front-loaded with the core capability, then example queries, then a compact English restatement. Dense but every clause carries information; the bilingual duplication costs some tokens without adding semantics.

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 read-only data tool with no output schema, the description covers data sources, measurement types, update frequency, coverage count and historical context. An agent has enough to invoke it correctly; only return-shape expectations remain unaddressed.

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 fully documented in the schema, including the empty-means-whole-island convention. The description only implicitly reinforces river-or-place scoping, so the baseline of 3 applies with no added syntax or format detail.

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: Vigicrues Réunion flood vigilance per river plus live water height and flow at 29 stations, with trends and historical flood references. Precise enough that an agent can distinguish it from vigilance_meteo or maree without opening any schema.

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?

Four example user questions (river flooding, vigilance status, ravine level, rising river at Salazie) clearly delimit the intended usage context. It does not name a sibling tool or state when to prefer an alternative such as vigilance_meteo, so it stops short of explicit routing guidance.

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