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

With no annotations provided, the description must fully disclose behavior. It only mentions a temperature lookup and fails to mention that many parameters are 'discarded after' checks (as noted in schema descriptions), that the tool likely performs multiple validations, or that it may have side effects beyond a simple read. The description is not transparent about the tool's actual operational breadth.

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, which is efficient, but it is under-specified and omits critical information about the tool's multi-purpose nature. It is not front-loaded with the most useful guidance; instead, it presents a narrow view that could mislead. While brevity is a plus, the lack of necessary scope details prevents a higher score.

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 tool has 9 parameters, no output schema, and no annotations. The description only covers one possible invocation (weather for a city) and completely ignores the other 8 parameters and their behaviors. For a tool of this complexity, the description is severely inadequate—an agent would not know how to handle parameters like 'ref', 'json', or 'path' correctly. This is far below the minimum viable completeness.

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 each parameter already has a description. The tool description adds no additional semantic value beyond what the schema provides; it only mentions the 'city' parameter implicitly. According to the calibration, a baseline of 3 is appropriate when the schema carries the full burden, and the description does not compensate with extra nuance.

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 specific verb and resource ('Current temperature for a city via Open-Meteo'), but it misrepresents the tool's actual scope. The input schema includes 9 parameters (ref, url, feed, json, path, zone, query, etc.) that have no weather relevance, suggesting the tool is a multi-purpose hint/validation tool rather than a dedicated weather lookup. The description does not differentiate from siblings like geo-hint or iana-zones, and could lead an agent to think this is exclusively for weather.

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 provided on when to use this tool versus alternatives. The description does not mention any exclusions, prerequisites, or contextual cues that would help an agent decide between this and sibling tools such as geo-hint or timezone. The agent is left to infer usage from the misleading weather-only description.

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