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

With no annotations, the description carries the full burden and does meaningful work: it discloses a blended NWS/station model, that every response labels the producing method, that pricing is dynamic ($0.01 for ≤48h, $0.03 beyond) via x402, and the HTTP surface. This is strong behavioral context a schema cannot express.

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 opening 'Hourly New York City weather forecast' is essentially repeated in the next sentence, wasting space, and the bracket block mixes useful pricing/docs with payload-irrelevant HTTP routing detail. Core information is front-loaded, but the redundancy and metadata density cost it.

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 simple read-only forecast with no output schema and no annotations, the description covers provenance, cost, horizon, and variables adequately. It is nonetheless incomplete on the units parameter and internally inconsistent on the hours cap (168 stated vs 240 in schema), which an agent could trip over.

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 0% and both parameters are required, so the description must compensate. It only loosely addresses the hours parameter ('up to 168 hours out' — which conflicts with the schema maximum of 240) and says nothing at all about the units enum (metric/imperial), leaving a required, enumerated parameter entirely unexplained.

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?

Names a specific verb (forecast), resource (hourly NYC weather), output variables (temperature, precipitation probability, wind), and horizon (up to 168 hours). It also distinguishes itself from the point sibling by explaining that NYC coordinates are built in, so an agent can tell it apart without opening another schema.

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?

City-specific naming implies when to use it, and the reference to the point endpoint hints at the alternative. However, it never states when to prefer this over weather_forecast-point or the similarly named weather_forecast-window_nyc sibling, and offers no exclusions or prerequisites.

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