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

No annotations are provided, so the description carries the burden. It discloses the pricing (5¢ per call), which is useful operational context, and implies a distance-based search behavior. However, it doesn't disclose what happens when no stop is found within the radius, whether results are sorted, or whether the output schema fully describes the response. The pricing disclosure is a plus, but behavioral details are thin.

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 two sentences plus a pricing note. It front-loads the core purpose, then gives a practical usage tip, then the cost. Every sentence earns its place with no fluff.

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 an output schema, so return values are presumably covered there. The description covers the core purpose and a key parameter adjustment. However, it doesn't explain what `gnaf_id` is, how to find it, or what happens when no transport stop is within the radius. For a simple two-parameter tool with an output schema, this is adequate but not complete.

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 50%: `radius_m` is well-documented in the schema, but `gnaf_id` has no description. The tool description adds the hint to widen `radius_m` beyond 1km, which adds practical meaning. However, it doesn't explain what `gnaf_id` is or how to obtain it, leaving a required parameter under-specified. The description partially compensates but doesn't fully cover the gap.

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 returns the nearest train/tram/bus/ferry stop to a property, per mode, with distance. It distinguishes itself from sibling tools like properties_amenities_nearby and properties_schools_nearby by specifying transport modes. However, it doesn't explicitly name a sibling alternative, so it falls just short of a 5.

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 gives a clear usage hint: widen `radius_m` for the nearest station beyond 1km. This implies the default radius may be too small for some searches and tells the agent when to adjust the parameter. It doesn't explicitly state when not to use this tool or name alternatives, but the context is clear enough for a property-focused transport lookup.

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