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

Annotations already declare readOnlyHint and openWorldHint, so the description builds on that by adding 'Deterministic — never estimates' and the fallback behavior for unmatched requests. It also clarifies that prices are per-vehicle, which is beyond the structured fields. No contradiction with annotations.

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 sentences, each packed with relevant information: exactness, live source, scope, determinism, and fallback behavior. No redundancy or filler. The most critical info 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?

With no output schema, the description adequately conveys return value semantics (exact per-vehicle prices) and the 'none' fallback. It does not detail output format or surcharge handling, but these are partially covered by the schema's time parameter and are less critical for a simple quote tool. Overall, it is reasonably complete.

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?

All parameters are fully described in the schema, so the baseline is 3. The description adds extra value by specifying valid place values for cruise terminal runs (e.g., 'Brisbane Cruise Terminal' or 'Pinkenba') and clarifying that prices are per-vehicle, which enhances the meaning of from/to parameters.

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's purpose: providing exact per-vehicle prices from a live fixed price list. It specifies the resource (fixed price list) and scope (airport transfers and cruise terminal runs), which distinguishes it from siblings like check_availability or request_booking.

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 gives clear context for when to use the tool (for specific airport transfers and cruise terminal runs) and provides a fallback instruction for 'none' matches. However, it does not explicitly contrast with alternative tools or state when not to use it, so it falls short of a 5.

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