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

With no annotations provided, the description must disclose behavior. It only states the output (temperature) and the data source (Open-Meteo). It does not mention that most input parameters are 'discarded' after checks, the specific return format, rate limits, or any side effects. The schema hints at discard semantics but the description fails to explain them.

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, concise sentence that states the core purpose. It is front-loaded with the key action and resource. While it could be more informative, the brevity is not excessive—it is just under-specified. It earns a 4 for clean structure without waste.

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?

Given 9 parameters, no output schema, and no annotations, the description is severely incomplete. It does not explain why there are parameters like 'ref', 'url', 'feed', 'host', etc., nor how they relate to weather. An agent cannot reliably invoke this tool correctly without understanding the parameter roles or expected outputs. The description is far from adequate for a tool of this complexity.

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 all parameters have descriptions in the schema. The description adds no extra meaning beyond what the schema provides—it only repeats 'city' implicitly. Since the schema covers parameter semantics fully, the baseline of 3 is appropriate; the description does not enhance it.

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 primary function: 'Current temperature for a city via Open-Meteo.' This is a specific verb+resource combination that distinguishes it from generic tools. However, it does not reconcile the presence of 9 unrelated parameters in the schema, which could confuse an agent about what the tool actually does.

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 guidance on when to use this tool versus alternatives. The description does not mention any exclusions, conditions, or alternative tools (e.g., geo-hint, timezone) that might be relevant. An agent has no context to decide between weather-hint and other location or hint tools.

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