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

With no annotations, the description carries the full burden of behavioral disclosure. It reveals the use of Open-Meteo but does not disclose that only the 'city' parameter is used and the others are ignored, nor does it mention rate limits, error behavior, or what happens with invalid inputs. The schema hints that parameters are 'discarded,' but the description adds no behavioral context beyond the basic operation.

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 sentence, which is concise and front-loaded with the core purpose. However, it is under-specified; the brevity is not a virtue because it omits essential usage and parameter information. It is structurally simple but lacks completeness.

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 optional parameters, no annotations, and no output schema, the description is severely incomplete. It does not explain what the tool returns, which parameters are actually used, how to handle the many irrelevant fields, or any limitations. An agent would be unable to call this tool correctly with confidence, as the schema is misleading and the description does not clarify.

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%, but the descriptions are generic and do not clarify which parameters are relevant to weather. For example, 'ref' is described as 'Git ref name; discarded after the shape check,' which is unrelated to weather. The description itself adds no parameter guidance, so an agent would be confused about how to fill the schema for a weather request. The description fails to compensate for the schema's misleading breadth.

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 clear purpose: 'Current temperature for a city via Open-Meteo.' It identifies the verb (get), resource (temperature for a city), and data source (Open-Meteo). It is distinguishable from siblings like geo-hint (geolocation) and timezone, though it does not explicitly name alternatives. The clarity is good but not perfect because the input schema implies many other uses.

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 no guidance on when to use this tool versus alternatives. It does not mention any exclusions or contexts, and does not reference sibling tools. An agent would not know whether to pick this over other hint tools based on the description alone.

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