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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety and idempotency. The description adds that the fare is fixed and all-inclusive, and that it returns the recommended car and booking page. It doesn't describe pagination, response format, or any quirks like route-specific behavior. Since annotations cover the safety profile and the description adds pricing semantics, a 3 is fair.

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, dense sentence that packs all key information: what it returns, pricing basis, scope, and ancillary outputs (recommended car, booking page). It's front-loaded with the core purpose and avoids redundancy. No wasted words.

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?

The tool is a read-only lookup with a clear scope, full parameter schema, and clear output expectations (fare, recommended car, page). It doesn't have an output schema, so the description's mention of 'recommended car and page to book' fills that gap. Missing details like currency conversion or availability are not critical for a fixed price lookup. The description is sufficiently complete for an agent to invoke 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 6 parameters are documented in the schema itself. The description adds context about the route type (London airports/cruise ports) and that vehicle can be omitted to get all four, but it doesn't go into parameter syntax beyond what's in the schema. With full coverage, baseline is 3, and the description modestly adds route context.

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 provides fixed one-way chauffeur fares in GBP per car, all-inclusive, for specific routes (London airport/cruise port to central London), by vehicle class, with the recommended car and booking page. The verb ('Fixed', 'get') and resource ('transfer price') are explicit, and the scope (routes, vehicle classes) differentiates it from siblings like get_hourly_price or get_meet_greet_price.

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 context: it's for fixed one-way fares between airports/cruise ports and central London. It does not explicitly state when not to use it (e.g., for hourly or meet-and-greet services), but the sibling names suggest alternatives. There's no explicit exclusion or alternative mention, but the tool's specific scope is clear enough. A 3 is appropriate because it gives context but doesn't contrast with alternatives.

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