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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context: results are scoped to Gatwick arrivals and the landing time is expressed in UK time, which matters for pickup planning. No mention of failure behavior for unknown flight numbers or how far ahead dates are valid.

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?

Two sentences, zero filler. The core capability and returned fields come first, and the use-case hint is compressed into a trailing clause rather than a paragraph.

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 usefully lists the four returned fields, so an agent knows what it will get back. It would be fully complete with a note on behavior for invalid or not-yet-scheduled flights, but for a simple two-parameter lookup it is largely sufficient.

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%, with both flight_number and date already documented including format and an example, so the schema carries the load. The description's only added nuance is that the landing time is UK time, which reinforces rather than extends the schema's 'UK date the flight lands'. 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 verb (check) and a bounded resource (a flight landing at Gatwick), then enumerates exactly what comes back: airline, origin, scheduled landing in UK time, and terminal. The Gatwick constraint makes the scope unambiguous even against the booking-oriented siblings.

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?

'Use for pickups from Gatwick' gives a concrete scenario that tells the agent when this tool is appropriate, tying it to the airport-transfer workflow. It does not name a when-not case or point to an alternative, 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.