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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds behavioral context by characterizing this as a 'Shorter' lookup, implying a summary response, and enumerates the specific output fields. It does not disclose potential edge cases like availability of Starlink status on all flights, but the key behavioral distinction from the sibling tool is clear.

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?

The description is two sentences long, front-loaded with the core purpose and fields, and ends with a practical pointer to the alternative tool. Every word earns its place; no filler or redundancy.

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 simple one-parameter lookup tool, the description sufficiently covers what the tool does, what it returns, and when to use a sibling tool. There is no output schema, but the description lists the output fields explicitly. It lacks details like response format or latency, but these are not critical for tool selection and 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?

The schema describes flight_number as an IATA flight number with examples, yielding 100% schema description coverage. The tool description only references 'flight number' without adding new semantic detail beyond the schema, so the baseline score of 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 clearly states the tool's function: 'Shorter WiFi lookup for a flight number' and lists the specific fields returned ('provider, confidence, airline, aircraft, and Starlink status'). It also distinguishes itself from the sibling get_wifi_facts by noting what it lacks ('date, tail number, or reasoning'), making the purpose 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?

The description explicitly tells the agent when to use this tool versus an alternative: 'Use get_wifi_facts instead when you need the date, tail number, or reasoning.' This provides a clear decision rule, indicating to use get_flight_wifi for a quick summary and get_wifi_facts for detailed info.

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