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

The description discloses the three possible return outcomes (FIRM YES, FIRM NO, probability estimate) and explains the temporal context of assignment publication. It also reveals the fall-through latency behavior, adding meaningful detail beyond the readOnly and idempotent annotations.

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 with no filler. The intended use case is front-loaded, return behavior is summarized compactly, and the sibling-tool routing is stated in the final sentence. Every sentence earns its place.

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 tool, the description covers the trigger, the response semantics, the relevant time horizon, and the alternative tool when appropriate. Since annotations and the fully described schema handle safety and parameter details, nothing essential is missing for correct invocation.

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 input schema already provides rich descriptions for date, flight_number, origin, and destination. The description adds some temporal meaning via 'assignments publish ~2 days out,' but the schema carries the primary parameter documentation burden, so the 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?

The description states a specific verb and resource: answering whether a specific United Airlines flight has Starlink/WiFi. It also distinguishes itself from predict_flight_starlink by defining the exact fallback behavior, making the tool's role unambiguous.

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?

It explicitly says 'Use when the user asks...' and gives a clear directive to call predict_flight_starlink directly for dates further out. This provides both a concrete trigger condition and an explicit alternative, which is exactly what an agent needs for selection.

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