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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context via 'current' (indicating live, time-sensitive pricing) and 'through Sail' (provider scope), but does not disclose ordering, currency, or failure handling. With annotations this is an acceptable level of transparency.

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, tightly-worded sentence that front-loads the action and includes the resource, scope, and time-sensitivity. There is no filler or repetition of the title.

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 read-only comparison tool with rich input schema, annotations, and an output schema, the description provides sufficient context about what the tool does and what data it returns. Minor gaps remain around when to use it versus plan_trip and how the resolved places should be obtained, but these are largely inferable from sibling names and schema descriptions.

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 100% description coverage, documenting lat/lng ranges, placeId provenance, and the required pickup/destination objects. The description adds no additional parameter-level detail, but none is needed given the thorough schema.

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 states a clear action ('Compare'), a specific resource ('current ride-hailing prices and pickup times'), and a scope ('providers available through Sail'). It does not explicitly contrast itself with sibling tools like plan_trip or plan_trotro_route, so it stops short of full sibling differentiation.

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 when to use the tool—when comparing ride-hailing options—but gives no explicit guidance on when to choose it over siblings, nor does it mention exclusions or prerequisites. An agent must infer the appropriate usage from the name and the sibling list.

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