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

Annotations declare readOnlyHint=true, so the safety profile is already covered. The description adds useful context by naming the returned fields (distance, time, legs) and the REST endpoint, but says nothing about API-key requirements, rate limits, or how many waypoints are permitted.

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?

Two compact sentences, front-loaded with purpose and return values; the REST endpoint note is slightly extraneous but harmless and informative.

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?

For a no-output-schema read tool, the description helpfully summarizes the return shape (distance, time, legs) and identifies the endpoint. It is largely complete, with minor gaps around authentication and response format options ('json' vs 'geojson') that the schema partially covers.

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%, so the schema already documents all six parameters including the pipe-separated waypoint format and mode values. The description only restates 'waypoints' and 'travel mode' without adding syntax or constraints beyond the schema, so the baseline 3 applies.

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?

States a specific verb ('Compute a route'), the resource (waypoints), the key parameter (travel mode), and the return payload (distance, time, legs). This clearly separates it from geocoding and isoline siblings, which do not compute point-to-point routes.

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?

Usage is implied — you call it when you need a route between waypoints — but there is no explicit when-to-use/when-not-to-use guidance and no mention of alternatives such as geoapify_isoline for reachability instead of routing.

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