Get current weather

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

With no annotations, the description carries the behavioral disclosure burden. It states what output to expect (conditions, temperature, feels-like, humidity, wind, recent precipitation) and notes that measurements are 'measured at the city's local time.' It does not mention error handling or units, but for a simple read-only weather tool, it provides sufficient transparency.

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 three sentences, each earning its place: purpose, what you get, and when to use an alternative. It is front-loaded with the main action and avoids fluff.

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 one-parameter tool with no output schema and no annotations, the description is remarkably complete. It covers what data is returned, when to use the tool, and the alternative for other time frames. No critical information seems missing.

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 'city' parameter has a detailed description ('written the way a person would say it'). The tool description adds no extra parameter information, so the baseline of 3 applies.

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 clearly states the tool's purpose: 'Find out what the weather is like in a city right now.' It specifies the resource (city weather) and the verb (find out/get current), and explicitly distinguishes from the sibling by advising 'If you need tomorrow or the days after, use get_forecast instead.'

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 explicit usage context: 'Use this for questions about the present moment' and gives examples of when it's appropriate. It also names an alternative tool for future forecasts, giving clear when-to-use vs. when-not-to-use guidance.

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