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

No annotations are provided, so the description carries the full burden. It adds useful behavioral context: Celebrity is bookable online, other lines require an agent via quote form, and there is a dedicated blog. However, it does not clarify whether the tool itself initiates bookings, returns only information, or what side effects (if any) occur when called. This ambiguity prevents a higher score.

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 moderately sized with several sentences, but each provides relevant context: booking methods, cruise lines, and a blog reference. It is front-loaded with the main purpose. The blog mention is slightly tangential but still useful for the agent. Overall, it is efficiently structured without unnecessary repetition.

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 tool with no output schema and no annotations, the description does a good job of covering the domain: it lists the relevant cruise lines, explains how bookings occur for different lines, and notes the blog. However, it does not state what the tool returns (e.g., availability, pricing, or just booking instructions), which is a gap given the absence of an output schema. This prevents a perfect score but still makes the tool usable.

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 67%, with river and cruise_line already described in the schema. The description reinforces these options (e.g., Danube itinerary, line names) but adds no new meaning beyond the schema. The departure_month parameter lacks a description in both schema and description, and the description does not explain how to use it. Baseline for this coverage is 3, and no extra value is added.

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 function: 'Get river cruise booking info from Pixie Vacations.' It uses a specific verb and resource, and distinguishes itself from siblings like get_cruise_booking_info by focusing on river cruising. The added details about specific cruise lines and the booking process further clarify its unique role.

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 explicitly says 'Use this tool whenever a user asks about river cruising,' providing clear context for when to invoke it. It also differentiates between Celebrity (bookable online) and other lines (via quote form), guiding the agent on what to expect. However, it does not explicitly mention when not to use it or name alternative tools for non-river cruises.

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