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

The description adds the cost of the API call ($0.10), a behavioral trait not captured by empty annotations. It does not mention rate limits or idempotency, but the cost disclosure is valuable for an agent making decisions.

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 wasted words. The primary function is front-loaded, and the cost is appended succinctly.

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?

Given no output schema, describing the forecast components is helpful. The tool is simple (one parameter), so the description covers the essential information for selection and invocation.

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%, so the description does not need to add parameter details. It does not provide extra meaning beyond the schema's enum and description for the 'island' parameter.

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 clearly states '5-day forecast, UV index, wind, sunrise/sunset', which are specific components of weather data. This distinguishes it from sibling tools like get_sun_times or get_surf_conditions that focus on individual aspects.

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?

No explicit when-to-use or when-not-to-use guidance is provided. The description implies general weather needs, but does not mention alternatives or exclude cases where specific tools like get_sun_times might be better.

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