Discover and Rank Complete Itineraries

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

Annotations already declare readOnlyHint=true, and the description adds the protobuf+HTTP transport and the top-1-3 return behavior, which is modest extra context. It does not explain ranking criteria, external-call semantics, or failure behavior, but the read-only annotation lowers the burden.

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 a single efficient sentence that front-loads the core action and result. It contains no filler, though 'Use protobuf+HTTP' is terse and could be more descriptive without becoming bloated.

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—a large nested request, an output schema, and two sibling tools—the description omits important context about what 'complete itineraries' means, how ranking works, and when to select this over the siblings. The output schema covers return structure, but behavioral and selection context are lacking.

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%, with the nested request object documented as 'One Google Flights search and the controls used by the ranking pipeline.' The description adds no parameter-level detail, so it does not exceed the baseline established by the rich schema.

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 states a concrete outcome ('pair full itineraries, rank them, and return top 1-3') and hints at a distinct mechanism ('protobuf+HTTP'), which helps separate it from the URL-building and verification siblings. However, 'pair' is jargon and not explained, so it stops short of a fully self-contained purpose statement.

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 tool versus build_protobuf_search_url or search_and_verify_top, and no mention of prerequisites or exclusions. The word 'Use' implies a general directive, but the description does not provide selection conditions or alternatives.

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