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

The description discloses that the tool automatically evaluates route options and recommends the best approach, and mentions internal processes like direction detection and backtracking analysis. This goes beyond the readOnlyHint annotation by providing insight into its decision-making, though it does not address potential limitations or edge cases.

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 succinct but informative, front-loaded with the purpose, and organized in a clear flow. It avoids unnecessary detail but packs in relevant capabilities without being verbose.

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 simple schema with full descriptions and no output schema, the description is complete in explaining the tool's function. It covers the types of routes evaluated, the recommendations made, and the internal handling of trip complexities, leaving no significant gaps.

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?

The description only references cities ('Give it your cities') and does not add any meaning to the pax, budget, or preferences parameters beyond what is already in the schema. Since the schema already fully describes each parameter, the tool description adds no additional semantic value.

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 clearly states the tool is the primary entry point for multi-city trip planning, specifically evaluating Star Alliance RTW, oneworld RTW, and custom mixed-carrier builds. It distinguishes itself from sibling tools by positioning as the comprehensive planner for any multi-city itinerary.

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 explicitly says it is for 'any multi-city trip' and acts as the 'primary entry point', making it clear when to use this tool over alternatives. It also mentions handling various route complexities, reinforcing its role as the go-to for full planning.

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