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

Annotations already declare readOnly/idempotent/non-destructive, so those are free. The description still adds real value by clarifying the output is informational links with no booking side effect, and by disclosing the ~100-airport geographic coverage so the agent knows the failure mode when an airport is unsupported.

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, front-loaded with the primary capability and closing with scope limits. Dense but readable; the EU/UK compensation clause is a distinct capability packed into the same sentence, which cost a little clarity.

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?

With an output schema present, return values need no explanation, and the description covers scope, no-booking behavior and geographic limits. The one gap is that sibling routing against sos_find_alternatives and sos_check_rights is left for the agent to infer.

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 description names the exact need categories (hotel, lounge, transfer) that map to the enum values and states the tool is airport-scoped. It corroborates rather than repeats, so it slightly exceeds the baseline 3.

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 (Lists) and concrete resources (hotel/lounge/transfer links, alternative airports, EU/UK compensation rules) for a clearly scoped subject (an airport). It distinguishes itself from the case/message siblings, but the overlap with sos_find_alternatives on 'nearby alternative airports with directions' is never acknowledged or resolved.

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 context is implied: use it when a traveller is stuck at an airport and needs accommodation, lounge or transfer options. 'Links only, nothing is booked' usefully bounds expectations, but there is no explicit when-to-use versus sos_find_alternatives or sos_check_rights, despite the description touching both of their domains.

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