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

The description adds real context beyond the annotations: it discloses the cost ('Uses one read') and a persistence side effect ('saves the result in the user's Puley history'), which usefully explains why readOnlyHint is false for a lookup-style tool. It also attributes the upstream data source (FlightAware), implying open-world, externally-dependent results. It stops short of covering failure modes or staleness of the live data.

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 answer content is front-loaded in the first clause and the enumerated status list is efficient. The single sentence is dense and slightly run-on with its long series of returned fields, but no sentence is filler.

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 one-parameter tool with no output schema, the description covers the return value in detail (status category, local times, gates, terminals, aircraft, other days), notes the cost and the history write, and explains the input format by example. What remains — date anchoring and unknown-flight behavior — is minor relative to a tool this simple.

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 0%, so the description must carry the parameter's meaning, and it does add value by naming it ('flight: the flight number') and giving varied format examples with and without spaces (BA117, UA 1, DL1). It does not clarify whether the lookup is anchored to today's date or how the 'same flight on other days' return is keyed, leaving a genuine ambiguity given the single free-text parameter.

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 names a precise resource and scope: real-time status of one flight from FlightAware, enumerated as on time/delayed/in the air/landed/cancelled/diverted, plus the specific data returned (local departure and arrival times, gates, terminals, aircraft, same flight on other days). This is clearly distinguishable from the search-oriented sibling find_flights, which locates flights rather than reporting one flight's current state.

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 'Where a flight is right now' — the agent can infer this is for looking up a known flight number, not for discovering flights. However, there is no explicit when-to-use versus find_flights, no note about when the answer would be ambiguous (e.g. multiple days or unknown flight numbers), and no exclusions.

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