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

Annotations already cover read-only and closed-world safety, and the description adds real value beyond them: data provenance (hourly forecast and official AEMET warnings) and freshness metadata (generation time and validity window per answer). It stops short of describing data-failure behavior or how warnings alter scores.

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?

Three tight sentences, front-loaded with the returned values before filtering and freshness. Nothing is padding, though the 'Each answer states when it was generated' sentence could be folded more compactly.

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?

With no output schema, the description does enumerate the returned fields (scores, water temp, wave height, wind) and their range, plus sourcing and validity. Adequate for a 3-optional-param read tool; only the response's structure for multi-beach listings is left unclear.

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% with enum and format guidance already in the schema. The description adds only that beach and region are optional filters and that omitting region means all, which duplicates the schema's own 'Omit for all'; the language parameter is not mentioned at all.

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 resource and verb: current swimming/family scores plus water temperature, wave height and wind for Mallorca beaches. It is clear on scope (Mallorca, current, 0-10 scores) but does not explicitly distinguish itself from the sibling best_beaches_now, which plausibly returns overlapping score 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?

Usage is only implied: fetch current conditions, optionally narrowing to a beach or region. The description names no alternative (e.g. best_beaches_now) or exclusion condition, so an agent must infer when this tool beats its siblings.

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