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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds that the underlying airline list may be incomplete, which is useful disclosure, but says nothing about ambiguous matches, no-match behavior, or whether one or many results come back.

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 compact sentences with no waste; the core lookup purpose and input formats come first, with the edge-case note last.

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 single-parameter lookup with no output schema, the description correctly states the return value and the accepted inputs. It could go further on match ambiguity or failure behavior, but nothing essential for invoking the tool is missing.

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 single parameter is already documented as "a flight number or an airline name." The description adds concrete format examples ("AC 857", "WestJet"), which clarify the accepted shapes beyond the schema's prose.

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 and resource plus the exact return value: an airline's 2-character code. The examples ("AC 857", "WestJet") and the resource (airline) make it unmistakable against siblings find_airport and check_flight_compensation.

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?

Explains the two accepted lookup modes (by flight number or by name) and adds a fallback hint that airlines not in the list can still be resolved by code. It doesn't name an alternative tool or state when not to use this one, but the context for calling it is clear.

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