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

The description discloses return behavior: 'Returns bookable cash and points options with pricing, cancellation terms, room details, and Gondola rate IDs.' This goes beyond the readOnlyHint annotation by describing the output content. It does not mention potential errors, rate limits, or side effects, but for a simple read-only operation, this is adequate. The annotation already signals safety, so the description adds useful output context without contradiction.

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 two sentences long, with no redundant phrases. It efficiently states the purpose, output, and usage context, and front-loads the core action. Every sentence contributes value, making it concise and well-structured.

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 tool's simplicity, the description covers the essential aspects: what it does, what it returns, and when to use it. It does not explain the output schema in detail, but that is acceptable since the output schema exists separately. The description is complete enough for an agent to decide whether to invoke this tool, though it could mention error conditions or edge cases (e.g., no availability) for full completeness.

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 already provides descriptions for all four parameters (hotel_id, checkin, checkout, num_adults) with types and default values, achieving 100% coverage. The description adds no extra semantic detail beyond what the schema provides (e.g., 'one hotel' implies hotel_id, 'stay window' implies checkin/checkout). Per the rubric, with high schema coverage, the baseline is 3, and the description does not elevate it.

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: 'Get current room rates for one hotel and stay window.' It specifies a verb (get), a resource (room rates), and scope (one hotel and stay window). It also lists the specific outputs (cash and points options, pricing, cancellation terms, room details, Gondola rate IDs) and differentiates from search_hotels by positioning it as a follow-up. This distinguishes it from sibling tools like compare_rates or get_multi_night_rates, though those are not explicitly named.

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 provides clear usage context: 'Use this after search_hotels when the traveler wants availability or booking options.' This gives a sequencing hint and a primary use case. However, it does not explicitly contrast with alternatives such as compare_rates (for comparing hotels) or get_multi_night_rates (for longer stays), leaving some ambiguity for an agent choosing among rate-related siblings. The single-hotel focus is implied but not explicitly stated as a differentiator.

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