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

Annotations already declare readOnlyHint and openWorldHint, so safety and freshness semantics are covered. The description adds genuinely non-schema context the annotations lack: per-call cost ($0.002 USDC via x402 on Base) and a free tier of 5 calls/day per client, which affects invocation decisions. It does not mention caching, latency, or data staleness, keeping it short of a 5.

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?

One dense sentence front-loads the purpose and return shape, then appends the payment terms; nothing is wasted. It is longer than strictly necessary in the event enumeration, but every clause carries information an agent would otherwise have to guess.

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?

There is no output schema, so the description carries the return-value burden and discharges it by naming the status categories, the severity scale, and the event types with delay metrics. Combined with cost and payment-rail info, an agent has everything needed to call and interpret the result.

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% and the single `code` parameter is fully documented with IATA/ICAO examples in the schema. The description adds only the constraint 'one US airport,' which reinforces the singular scope, 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 resource (current FAA status for one US airport) and enumerates exactly what comes back: status level, max severity 0-5, and each active event type. This is far more than a tautology and an agent knows precisely what it gets. It does not, however, mention or contrast with the sibling us_airport_disruptions, so differentiation is left to inference.

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 implied by the scope ('one US airport') rather than stated: there is no when-to-use, when-not-to-use, or reference to the overlapping sibling us_airport_disruptions. The pricing sentence tells the agent what a call costs but not when a call is the right choice over an alternative.

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