compare_routes

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds a useful behavioral caveat ('Motorbike times are estimates') and geographic scope, but does not disclose details like data freshness, response format, or how transit modes are computed. This is adequate but not rich.

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 tight sentences deliver the core purpose, the mode list, the geographic scope, and the key caveat with no filler. The most important information is front-loaded.

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 rich input schema, the output schema, and annotations, the description covers the essential behavioral context. Nothing critical is missing for an agent to understand what the tool does and how to invoke it correctly.

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 all parameters are already documented with meaningful descriptions. The tool description introduces the set of modes referenced by the modes parameter but adds no new semantics beyond what the schema provides.

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 a specific action ('Compare door-to-door travel time') on a specific resource (travel between two places in Île-de-France) and enumerates the comparison modes. It is immediately distinct from sibling tools like get_weather or find_place.

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 conveys a clear use case: comparing door-to-door travel times across specific modes within a geographic scope. It does not explicitly name alternatives or exclusions, but the context is strong enough that an agent can infer when to use this tool versus the siblings.

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