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

Annotations provide no readOnly or destructive hints, so the description carries the full burden. It only says 'look up the weather' and gives no information about response format, default behavior, limitations, or whether this returns current conditions or a forecast. This is a notable gap for an unannotated tool.

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, front-loaded sentence with no redundancy. It is concise and easy to parse, though it sacrifices useful context for brevity.

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?

The description plus the fully documented schema is minimally viable for a simple weather lookup: place, day, and focus are all explained. However, with no output schema and four similarly named weather_* siblings, the definition does not fully clarify when to choose this tool or what kind of response to expect.

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 the schema already documents all three parameters well. The description only restates the 'place' concept and adds no meaning for the day or focus parameters beyond what the schema provides.

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 concrete action ('Look up') and resource ('the weather'), scoped by location type ('town or city name'). It is clear on its own, but it does not differentiate from sibling weather tools like weather_forecast, weather_history, weather_air, or weather_marine.

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?

No guidance is given about when to use this tool instead of the other weather_* siblings. There are no explicit conditions, exclusions, or alternatives mentioned, leaving the agent to infer usage from the name and terse description.

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