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

No annotations are provided, so the description carries the full burden for behavioral disclosure. The description is straightfoward: it 'finds' stations, which implies a read operation. It adds a useful hint about the return type (station ID format) and how to use it downstream. However, it doesn't disclose any potential failures (e.g., what happens if no stations are found), any rate limits, or whether the required coordinates are validated for proximity. The description adds some value but is not deeply informative about behavior.

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 concise: one sentence with a clear action and a helpful downsteam usage tip. It is front-loaded with the core purpose and then adds the valuable station-ID hint. No wasted words. It could potentially describe the coordinates more, but for a simple lookup tool, it's appropriately sized.

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 the tool's simplicity (3 params, no output schema), the description is adequately complete. It states the resource type (official weather stations), the domain (Frost), and a downstream use case. It doesn't describe the return structure (e.g., does it return a list of stations with their own coordinates?), but the agent can likely infer that from 'find stations' and the schema. The lack of an output schema means the description could be more descriptive about the response shape, but it's not critical for an agent to invoke the tool correctly.

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%, so the schema already documents all three parameters (latitude, longitude, count) including their constraints and defaults. The description adds the fact that stations are 'nearest' to the given coordinates, which clarifies the role of latitude/longitude, but that's implicit in the schema. The description does not add any details about count or its behavior beyond what the schema says. Since coverage is high, baseline 3 is appropriate.

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: 'Find the nearest official weather stations (Frost).' It clearly indicates the tool's function and hints at the domain (meteorological data). It doesn't explicitly differentiate from siblings, but the reference to 'Frost' and the station ID gives it a unique identity. The description is clear enough that an agent can distinguish it from the other weather-related tools based on the resource it targets.

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 usage guidance by telling the agent to use the station ID with get_historical_weather. This implicitly states that the tool is a prerequisite for another tool, which is useful routing information. However, it doesn't explicitly state when NOT to use this tool or mention alternatives (e.g., get_nowcast or get_forecast might also need station IDs, but that's not stated). The guidance is clear but could be more explicit about exclusions.

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