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

There are no annotations, so the description must carry behavioral details. It states the core behavior (returns nearest stops with distance) but does not mention error handling, sorting guarantees beyond 'nearest', radius application details, or any limits on result size beyond the schema's max_results. It also does not clarify whether the tool is read-only or how it behaves when no stops are found.

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 is well-structured and front-loaded with the core action ('Reverse-geocode a coordinate'). It avoids unnecessary verbiage and flows logically, making it easy to parse.

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 description adequately conveys that the tool returns nearby stops with distances and that IDs can be used further, but since there is no output schema, it lacks detail on the exact structure (e.g., whether it includes names, coordinates, or just IDs). It also does not mention potential edge cases or how the radius interacts with the 'nearest' criterion, leaving some contextual gaps.

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% (all parameters have descriptions). The description itself adds no new meaning to the parameters; it only mentions 'nearest' and 'distance' which relate to the result rather than the inputs. Per the rubric, with high schema coverage, a score of 3 is the baseline, and no additional parameter context is provided.

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 action: reverse-geocode a coordinate to the nearest public transport stop places (Entur) and return each with its distance. It also hints at the intended downstream use of the IDs with departure and trip tools, which reinforces the purpose.

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 mentions using the returned IDs with departure/trip tools but does not explicitly contrast this tool with sibling tools like find_place_names_near or find_docking_stations. It lacks explicit guidance on when to prefer this over alternatives, though the fact that it specifically targets public transport stops is implicit.

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