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

Beyond the readOnlyHint, idempotentHint, and destructiveHint annotations, the description discloses meaningful behavioral facts: it 'returns search links only: no live prices, no availability and no booking', notes affiliate commission and disclosure obligations, and explains that results are regionalized and prefilled. These are material behaviors an agent cannot infer from the schema or annotations alone.

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 front-loaded with the core purpose and scope, then moves to usage guidance, limitations, and the affiliate disclosure. Every sentence carries distinct information, and there is no filler or repetition of schema details.

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?

Given the tool's complexity — 9 optional parameters, an output schema, and a large sibling set — the description covers purpose, scope, selection criteria, alternatives, limitations, and even a compliance note about affiliate links. An agent has enough context to decide whether to invoke it and what to expect from the result.

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%, so the baseline is 3. The description adds value by explaining that route IATA codes, a city, and trip dates cause flight and hotel links to be prefilled, and that the 'include' parameter selects which categories are returned, with the car-rental example reinforcing optionality. This goes beyond simply restating parameter names.

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 opens with a specific verb and resource: 'Return one set of booking and shopping links covering a whole trip in a single call'. It enumerates the exact categories and explicitly contrasts itself with per-topic siblings like get_flight_links, so an agent can clearly distinguish this aggregate tool from more detailed single-category tools.

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 says it is 'useful when a user is planning a trip end to end and wants every option in one place' and then names the alternative: 'Each per-topic tool ... returns richer detail and more guides for a single category.' This gives an agent an explicit when-to-use versus when-to-prefer-alternative decision rule.

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