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

With no annotations the description carries the full burden, and it discloses the HTTP method (GET), the payment model ($0.02 via x402), the default behavior (omit times → next six hours) and the return content. It stops short of describing the response structure or payment/auth flow mechanics, but adds substantial context beyond any structured field.

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-loads the question the agent cares about, then the operational details. Every sentence contributes, though the bracketed HTTP/pricing/docs footer is somewhat dense for its placement.

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 no-annotation, no-output-schema tool, the description covers scope, defaults, limits, return content, and cost. An agent could call it correctly from this text; only error/response-format specifics are absent.

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%, so both parameters (start, end) and their ISO-8601 format, defaults, and the ≤12h constraint are already documented in the schema. The description restates the omit-for-six-hours default but adds no syntax or edge-case detail beyond it, matching the baseline 3.

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+resource ('Will it rain in Atlanta during your event window') and the exact output ('rain probability and expected conditions across the window'). The 'window' framing plus 'Same shape as /v1/forecast/window with the Atlanta coordinates built in' distinguishes it from the sibling point-forecast weather_forecast_atlanta and the generic window tool.

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 gives usage context ('built for scheduling decisions') and how to scope the call (pass start/end or omit for next six hours), but never states when to prefer this over weather_forecast_atlanta or weather_forecast-window. Usage is implied rather than routed against alternatives.

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