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

The description consistently portrays a read-only search operation, which aligns with readOnlyHint=true but directly conflicts with destructiveHint=true. An agent receiving destructiveHint=true may incorrectly assume the tool can change or destroy state, even though the description describes only searching. This internal contradiction undermines behavioral transparency despite the rich added context about quotas, sign-in, and coverage. Per rubric, a direct contradiction with an annotation yields score 1.

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 front-loaded with the primary purpose and parallel behavior. Every subsequent sentence earns its place: live-list measurement, coverage reporting, single-airline alternative, recommended usage, sign-in requirement, and free/premium limits. There is no redundant filler, and the logical order flows from what the tool does to when and how to use it.

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 that there is no output schema, the description reasonably explains the return shape by mentioning response grouped by airline and a coverage field, and it covers auth requirements, rate limits, and alternative routing. The only notable gap is that it doesn't specify the detailed structure of the returned award availability entries beyond grouping, but the provided context is probably sufficient for an agent to select and invoke the tool 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 coverage is 100%, with each of the ive parameters already documented in the input schema. The description adds meaningful operational caveats beyond the schema: free accounts are restricted to economy, cabin default behavior is clarified, flex_days only affects seats.aero results, and the response includes a coverage field. These nuances make the definition more actionable, though the description doesn't systematically enumerate each parameter.

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 clear, specific statement: 'Search award flight availability across every airline currently LIVE for a route and date, in parallel.' It identifies the resource (award flight availability), scope (every airline currently live), and mode (parallel). It also differentiates the tool from alternatives by emphasizing that any catalogued airline can be requested individually via search_availability.

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 is explicit: 'This is the recommended starting point — use single-airline search only if you need a specific airline.' It also names search_availability as the alternative and points to list_supported_airlines for understanding the live list. It clearly explains when the broader fan-out search is appropriate and when it is not.

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