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

Annotations already cover the safety profile (readOnly, openWorld, non-destructive), so the bar is lower; the description adds non-obvious behavior beyond structure — the per-call price ($0.0045 USDC via x402 on Base/Solana/Polygon/Arbitrum), that x402 MCP clients auto-pay, and that general-aviation-only closures surface as notices rather than closures. Missing only rate-limit/refresh-cadence detail.

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?

Front-loads what the tool does, then the parameter branching, then constraints. The pricing and free-sample sentences are useful but lengthen the block; everything still earns its place, though it is denser than strictly needed.

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 no output schema, the description carries the return-value burden and does so by naming the status values (normal, delays, disrupted) and event types. Payment and addressability are covered. Only minor gaps remain around freshness/pagination, which are not critical for a single-call status lookup.

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% and the single param is documented, but the description adds real semantics the schema lacks: codes may be IATA (JFK) or ICAO (KJFK), the list is optional, and omitting it changes the result set entirely rather than just narrowing it. That is meaningful value over the schema text.

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+resource ('Live US airport disruptions from the FAA National Airspace System status') and enumerates exactly what is returned: ground stops, GDP delays, arrival/departure trends, closures. No aviation sibling exists, so the scope is unambiguous and an agent can tell instantly what this tool covers.

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?

Explicitly states the branching condition: pass airports for per-airport status, omit them to get all current events, and notes the 'US airports only' constraint. It even supplies a concrete sample input, leaving nothing to inference about when to call and how.

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