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

No annotations are provided, so the description carries the full behavioral burden. It discloses one useful trait (the 7-day horizon), but says nothing about units, city-name format or ambiguity handling, geographic coverage, or failure behavior for unknown cities.

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?

A single front-loaded phrase with zero padding; the forecast horizon and input scope come first. It is a fragment rather than a sentence, but nothing is wasted.

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 one-parameter tool with no output schema this is close to adequate, but with no annotations and a directly competing sibling (get_weather), the description should at minimum clarify the return shape and how it differs from current-conditions weather.

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% for the single 'city' parameter, so the baseline is 3. The phrase 'any city' loosely signals that free-form city names are accepted, but adds no format or disambiguation detail beyond the schema.

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 resource and scope: '7-day weather forecast for any city' tells the agent exactly what is returned and the forecast horizon. However, it makes no attempt to distinguish itself from the sibling get_weather, so an agent cannot tell which of the two weather tools to pick from the description alone.

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?

There is no when-to-use guidance, no mention of the sibling get_weather, and no exclusion criteria. The agent is left to infer that this is the multi-day option while get_weather is presumably current conditions, which is an assumption, not guidance.

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