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

Annotations already signal readOnly and non-destructive intent, and the description adds substantial behavioral context: rate sources may still be loading and require a retry, only Gondola-bookable rates appear, other variants are collapsed, and past dates return a notice instead of rates. There is 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?

The description is dense but every sentence earns its place: core purpose first, then result structure, filtering rules, loading caveat, past-date behavior, and usage context. There is no fluff or 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 read-only rate lookup with an output schema present, the description covers all decision-relevant behavior: result shape, bookable-source filtering, eventual consistency, past-date handling, and how the output feeds get_booking_link and book_hotel. Nothing an agent needs to invoke it correctly is missing.

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 coverage is 100%, so parameters are fully documented by the input schema. The description contributes context around the overall use case and the downstream rate_id, but does not add much parameter-specific meaning beyond what the schema provides.

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 opens with a specific verb and resource: 'Get live room rates for one hotel and stay window.' It further distinguishes the tool by describing the unique rate grouping, filtering to bookable sources, and the rate_id used by booking tools, so an agent can differentiate it from siblings like compare_rates or get_multi_night_rates.

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?

It states when to use the tool: 'Use this after search_hotels when the traveler wants availability or booking options.' It does not explicitly name competing siblings or exclusions, but the 'one hotel' scope and downstream references make the intended context clear.

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