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

Annotations already declare the read-only, idempotent, non-destructive, open-world profile. The description adds value beyond that by disclosing the returned payload shape (pagination, cycle, provenance) and an explicit data-reliability caveat ('Reference data only; verify all performance and operational decisions independently'), which an agent needs to use the output responsibly.

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?

Three sentences, front-loaded with purpose, then return shape, then use cases and caveat. Every sentence contributes; the filter enumeration is slightly redundant against the schema but remains readable and appropriately sized.

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 an 11-parameter, no-required-filter tool with no output schema, the description compensates by summarizing both the filter surface and the returned fields, plus a caveat. It is complete enough to invoke correctly, though it omits pagination semantics (defaults, offset interaction) that the schema only partially covers.

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%, so every parameter is already documented in the schema with bounds and examples. The description only enumerates filter categories (state, length/width, surface, lighting, ILS, public use, status) without adding syntax or format detail, so baseline 3 is appropriate.

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 (Search) and resource (U.S. FAA NASR runways) with scope. The runway focus cleanly distinguishes it from the sibling faa_public_aviation_search_airports, which operates at airport granularity, so an agent can route between them without opening schemas.

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?

Gives concrete invocation examples ('operational Texas runways at least 8,000 feet', 'public-use paved runways in Alaska', airport-site screening) that clarify the intended use context. However, it never names an alternative tool or states when NOT to use this one versus the airport-level siblings, so it stops short of full routing guidance.

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