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

No annotations provided, so description carries full disclosure burden. It effectively communicates geographic restriction (US only) and temporal limits (up to 48 hours), but omits error handling behavior, rate limits, and data freshness guarantees.

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?

Three sentences with zero waste: purpose statement, usage examples, and behavioral scope. Information is front-loaded with the core action, making it immediately scannable for an agent.

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 low-complexity tool (2 primitive parameters, no nesting), the description adequately compensates for missing output schema by stating it 'Provides detailed hourly conditions.' Coverage of US boundary constraints and 48-hour limits provides sufficient context for correct 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?

Input schema has 100% description coverage with detailed examples (coordinate format, hour ranges). Description reinforces these constraints ('up to 48 hours', 'United States') but adds no additional semantic depth beyond what the schema already provides, meeting the baseline for high-coverage schemas.

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?

Description opens with specific verb-resource combination ('Get hour-by-hour weather forecast') and clearly scopes to US locations. The 'hour-by-hour' granularity explicitly distinguishes this from siblings like get_current_weather and get_weather_forecast.

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?

Provides clear usage context through example questions ('What's the hourly forecast?', 'Will it rain this afternoon...'), effectively signaling when to use the tool. Lacks explicit negative guidance or named sibling alternatives (e.g., 'use get_weather_forecast for daily summaries').

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