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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real value beyond them: a hard 7-day recency limit, no API key/free access, the returned data fields, and the presence of a link for out-of-range dates. Return format detail is thin but adequate for a simple query.

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 dense sentence plus two short clarifiers; the recency scope and field list are front-loaded. The trailing link instruction is slightly compressed but earns its place by handling the out-of-range case.

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 compensates by enumerating the returned fields and noting the link. The 7-day limitation and its workaround are stated. Only the sibling-routing for older dates is left underspecified.

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%, with date (UTC, YYYY-MM-DD) and callsign (ICAO) fully documented, so the baseline is 3. The description adds one meaningful constraint — the date must fall within the last 7 days — but does not otherwise extend parameter meaning.

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?

Uses a clear verb-plus-resource framing ('What happened to a flight on a given day') and enumerates the returned fields (airports, scheduled/actual take-off, delay, status, aircraft). The 7-day window further scopes the tool. It stops short of naming a sibling like flight_history or flight_status to differentiate itself, so an agent must infer the boundary.

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 a clear usage condition — dates within the last 7 days — and an explicit exclusion: for older dates, redirect the user via the returned link. It does not name the specific alternative tool (e.g. flight_history) for historical lookups, leaving routing partially implicit.

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