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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this by stating 'does not book or take payment'. It adds valuable behavioral detail: prices are per-traveler and include taxes/fees, and the returned link opens the same search for booking completion. This goes beyond the annotations in describing what the tool actually returns.

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: the first states the action, the second describes the return value and booking link, the third confirms safety and integration guidance. Every sentence earns its place, with no fluff or repetition. Front-loaded with the main purpose.

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 (11 params, output schema present, clear annotations), the description covers all essentials: scope (round-trip), pricing inclusivity, booking link, safety, and how to combine with other tools. The output schema exists, so return values are already documented. The description is complete for an agent to select and invoke this tool appropriately.

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% as every one of the 11 parameters has a description in the input schema. The tool description only vaguely references 'two airports', 'given dates and travelers', which maps to the obvious required parameters but adds no new parameter-level details beyond the schema. Baseline of 3 is appropriate since the schema carries the parameter semantics.

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 begins with the specific verb 'Search' and the resource 'round-trip flights between two airports', making the tool's core function immediate and unambiguous. It distinguishes from sibling tools (search_hotels, search_experiences) by explicitly focusing on flights and mentioning integration with build_trip for combined trips.

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 states this tool is for round-trip flight searches and is read-only, which helps set expectations. It also points to build_trip as the way to combine flights with hotels/experiences, giving a clear usage context. However, it does not explicitly state alternatives for one-way searches or when to prefer a different tool, though the sibling names make this reasonably inferable.

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