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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value: results are sorted best-first and beaches lacking a valid current forecast are silently dropped. It does not say what happens when no beach qualifies or how results are truncated by limit.

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 sentences, zero waste, with the ranking rule and the ordering front-loaded before the inclusion caveat. Nothing is repeated from the title or schema.

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 conveys the ordering and the filtering rule, which are the key unknowns for a ranked-list tool, and all four params are optional and schema-documented. It stops short of describing the return shape or the empty-result case, a minor but real 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?

Schema coverage is 100% with enums and defaults documented inline for mode, region, limit and language. The description only echoes the mode distinction (swimming vs family) and adds no syntax, fallback or defaulting detail beyond the schema, so baseline 3 applies.

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 states a specific resource (Mallorca beaches), a ranking criterion (highest current score for swimming or a family visit) and an output ordering (best first). This clearly separates it from list_beaches (an unfiltered inventory) and get_conditions (raw forecast data), even though no sibling is named explicitly.

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 implied rather than stated: 'highest current score for swimming or for a family visit' signals the two selection modes, and 'only beaches with a valid current forecast are included' tells the agent results are pre-filtered. There is no explicit guidance on when to prefer this over list_beaches or get_conditions, and no exclusions.

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