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

Annotations already declare readOnly, idempotent, and non-destructive. The description adds behavioral context (turn-by-turn, distance, time, source), which is consistent. No contradictions. A slight gap: it doesn't mention that results are based on OSM data limits or attribution.

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?

Single sentence, front-loaded with purpose, travel modes, and data source. Every word adds value. No redundant phrases. Ideal for quick scanning.

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?

With 7 parameters, 100% schema coverage, output schema present, and annotations covering safety, the description is sufficient. It covers the core functionality and key options. Minor omission: defaults for mode/lang/units are only in schema, but that's acceptable given schema coverage.

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 baseline 3. The description adds value by mentioning travel modes explicitly, which the schema lists as an enum, and by indicating return types (distance, time). This reduces ambiguity beyond the schema alone.

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 it retrieves turn-by-turn directions for multiple travel modes (driving, walking, cycling, transit) between two points, including distance and time, and specifies the data source (Geoapify/OSM). This distinguishes it from sibling tools like geocoding or place search.

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 implies usage for routing directions, but lacks explicit guidance on when to choose this over geo.address.geocode (for coordinates) or geo.navigation.isochrone (for reachable areas). The travel mode enumeration helps, but explicit comparisons would strengthen clarity.

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