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

With no annotations, the description carries the full burden and does most of it well: it discloses the upstream provider, that a FLIGHTAWARE_API_KEY secret is required, and that each call bills AeroAPI usage — cost and auth facts the agent cannot get elsewhere. It stops short of describing failure behavior (unknown ident, no-data responses) or how stale cached results may be, which matters given the no_cache escape hatch in the schema.

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 tight sentences, front-loaded with the outcome and ending with the two call-time constraints (secret, billing) that an agent most needs before invoking. The comma-heavy enumeration of returned fields is dense but each item earns its place; nothing is padded.

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 a read-only lookup with no annotations and no output schema, the description covers what an agent needs: what comes back, what it costs, what credential is required. The remaining gap is the relationship to the sibling tool and any error/empty-result expectations, neither of which is addressed.

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% — ident formats, no_cache cache bypass, and per-page billing for max_pages are all documented in the schema itself. The description adds no parameter-level meaning beyond the passing mention that calls bill usage, so the baseline of 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 and resource ("Live or planned status of a flight") and enumerates the returned data: times, delays, gates/terminals, aircraft, progress, cancellation/diversion flags, plus tracking links. "Operational data, not prices" sharpens the boundary against fare tools. It never names or characterizes the sibling flightaware_search_scheduled, so an agent must infer the split from the name alone.

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 "Live or planned status of a flight" — call it when you hold an ident and want current or scheduled status. There is no explicit when-not statement and no routing to the sibling search tool, even though one exists and the two could easily be confused.

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