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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered without the description. The description adds only 'with their page links', which is a thin hint about returned fields; it says nothing about empty results, whether airlines are deduplicated, or how errors on invalid terminals behave. For a read-only list tool the bar is low, but the description contributes almost nothing beyond the 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?

One short, front-loaded sentence fragment with no filler or redundancy. It is efficient, though it reads more like a subtitle than a purpose statement, and a few extra words stating the verb and required input would have been more useful than the brevity.

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?

The tool is simple (one required param, no output schema), and annotations plus schema cover safety and input format, but the description still omits what is actually returned (a list of airline objects? names only? link format?) and does not confirm that the terminal slug comes from search_terminals. For a tool whose name promises a list, the return contract is left ambiguous.

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% and the single 'terminal' parameter is already documented as a slug with a pointer to search_terminals for discovery. The description adds no further meaning, but with complete schema coverage the baseline of 3 applies rather than penalizing the silence.

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 fragment 'The airlines recorded as operating from a terminal' says what the resource is and scopes it to a terminal, which implicitly differentiates it from list_airlines (all airlines). However, it never states the verb (list/retrieve) and reads as a near-restatement of the tool name 'list_terminal_airlines', so an agent gets the gist but not a crisp statement of the operation. The added '+ page links' hints at return shape but is vague.

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?

There is no guidance on when to use this versus list_airlines, get_terminal, search_terminals, or get_airline. The description implies a terminal is required but never says so, nor does it mention prerequisites or what happens with an unknown slug. Any routing to alternatives must be inferred by the agent.

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