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

Annotations already declare this as read-only and non-destructive, so the safety profile is covered. The description adds that the forecast is tied to the household's location and limits the range to one-to-five days, but does not go into additional behavioral details such as return structure or error cases. It does not contradict the annotations.

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 a single, well-structured sentence that front-loads the verb and resource, then adds location and intended use. Every phrase earns its place; there is no redundant or filler content.

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?

With one optional parameter, an output schema present, and read-only annotations, the description provides all necessary operational context: purpose, location scope, and forecast duration. An agent has enough information to invoke the tool correctly without further disambiguation.

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%; the schema fully documents forecastDays, including range and default. The description's 'one-to-five day' phrasing mirrors the schema but adds no new parameter meaning beyond what is already structured.

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 states a specific verb ('Return'), a clear resource ('forecast'), and a defined scope ('one-to-five day forecast for the household's location'). This unambiguously differentiates it from the sibling tools, none of which relate to weather or forecasting.

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?

The description provides a clear use case ('for planning outdoor tasks or events'), which signals when an agent should consider this tool. It does not explicitly mention exclusions or alternatives, but there are no competing weather-related sibling tools, so the guidance is sufficient.

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