Current conditions and forecast for coordinates

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

With no annotations, the description carries full burden and does well: discloses data source (Open-Meteo), cost ($0.003 USDC), payment mechanism (EVM_PRIVATE_KEY), output format (WMO code + text), and a model-output caveat. This is thorough behavioral context.

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 description is two dense sentences covering scope, output fields, data caveats, complementary tools, and cost. Every sentence earns its place and the most important info is front-loaded.

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?

Despite having no output schema, the description enumerates current and forecast fields, return encoding (WMO + text), model output note, and cost. It is self-sufficient for an agent to understand what will be returned and how to invoke it.

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?

The schema already covers all 3 parameters with descriptions (100% coverage). The description adds context by confirming 'any coordinates worldwide' and 'up to a 7-day daily forecast,' reinforcing the meaning of lat/lon/days without redundancy.

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 what the tool does: 'Weather for any coordinates worldwide' with a detailed list of current conditions and forecast data. It is specific and distinct from sibling tools like geocode and web_search.

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 usage context by saying 'Pair with geocode to go from a place name to coordinates,' indicating when this tool is appropriate. It doesn't explicitly exclude alternatives, but no competing weather tool exists among siblings.

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