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

Annotations already declare readOnly, idempotent and non-destructive behavior, so the safety profile is covered. The description still adds real value beyond them: it discloses the estimation methodology (cwsi.net's calculator plus the airline's published rules) and an 'Unofficial' disclaimer the agent would otherwise not know.

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?

A single front-loaded sentence whose parenthetical adds scope rather than padding, capped by a two-word disclaimer. No sentence is wasted.

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 an output schema present, return values need no explanation, and all parameters plus the safety profile are covered by structured fields. The only missing piece is any hint about input units beyond the schema or what 'status credit where it applies' means in practice, which is minor.

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 100% — both 'price' (qualified spend ex-taxes/fees) and 'card' (the AV enum worth 3 points per $1) are fully documented in the schema. The description adds no parameter-level detail beyond that, so the baseline 3 applies.

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?

States a specific verb (Estimate) plus the exact resource (an Allegiant Air ticket's earnings), and even names the reward currencies involved (miles/points, status credit). This distinguishes it cleanly from the dozens of sibling airline calculators, which differ only by carrier.

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?

Usage is only implied by the airline name — an agent can infer it applies to Allegiant earnings, but the description gives no explicit when-to-use guidance and never mentions relevant siblings such as calculate_flight_distance or compare_fare_classes. Adequate but with a clear routing gap.

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