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

No annotations are provided, so the description carries full burden for behavioral disclosure. It mentions 'public OSRM engine', which hints at third-party dependency and possible availability/rate limits, but does not explain any behavioral traits such as whether the computation is free, what error conditions exist, or if it respects traffic or time-of-day. For a tool with no annotations, this is insufficient.

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 that is front-loaded with the key action and result. It contains no extraneous words and efficiently conveys the core functionality.

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 absence of an output schema, the description should explain what the return value contains (e.g., distance in kilometers, duration in seconds). It does not. Additionally, it does not mention coordinate order (lat, lng is implied by parameter names), typical ranges, or that the engine is free and public. For a tool with four required numeric inputs and no output schema, the description is too sparse to fully prepare an agent for correct invocation and interpretation.

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?

The input schema has 0% description coverage for parameters, so the description must compensate. It only says 'between two coordinates', implying start and end, but does not elaborate on the meaning of lat/lng values or their ranges (e.g., correct order, decimal precision). The parameters are named clearly, but additional context like coordinate system (WGS84) or unit expectations would help.

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 computes the shortest driving distance and duration between two coordinates using the OSRM engine. It uses a specific verb ('computes'), identifies the resource ('driving distance and duration'), and specifies the inputs (coordinates). This distinguishes it from sibling tools like getTollCost or getAirQuality, which have different purposes.

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 does not provide any guidance on when to use this tool versus alternatives, nor does it mention prerequisites, limitations, or exclusions. While siblings cover distinct domains, there is no explicit statement about when this route data is preferable (e.g., for driving vs. walking) or when not to use it.

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