Live current weather for a city

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

Annotations already declare readOnlyHint, idempotentHint, etc. The description adds value by disclosing the data source (Open-Meteo), pricing per call, and the specific fields returned. This goes beyond annotations to clarify what the tool does. No rate limits or error scenarios are mentioned, but the safety profile is well covered by 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?

Two sentences fully capture the tool's purpose, output, source, and pricing. Every word adds value; no redundancy or filler. Front-loaded with the core function.

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 strong annotations and no output schema, the description covers the return format, source, and pricing. It lacks details like error handling for invalid cities or pagination, but such depth is not critical for this low-complexity tool. Minor gap: no mention of whether the output is structured or raw.

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 coverage is 100%: the 'city' parameter is described with a name, example, and default. The tool description reinforces that it works for 'any city' and lists output fields, but this adds only marginal context beyond the schema. Baseline 3 is appropriate given high schema coverage and no additional parameter constraints.

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 it provides 'live current weather conditions' with specific data points (temperature, conditions, humidity, wind). The verb 'provides' and resource 'weather for any city' are unambiguous. No sibling tool offers weather, so differentiation is inherent, but the description itself is self-sufficient.

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 does not explicitly state when to use or avoid this tool versus alternatives like web_search for weather. Usage is implied by the name and description, but there is no guidance on prerequisites (e.g., valid city names) or exclusion of edge cases. Pricing is mentioned but not framed as a usage consideration.

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