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

While annotations handle the safety aspect (readOnlyHint), the description provides high-value behavioral context by specifying *what* kind of data is returned (e.g., 'seasonal mountain passes,' 'cost estimate'), which helps the agent determine if the tool satisfies a complex user query.

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 highly efficient, structuring a massive amount of information into a single, dense sentence where every phrase defines a capability or constraint of the tool.

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 that there is no output schema, the description is exceptionally complete, covering the depth of the itinerary, the inclusion of external links, and the types of metadata (like cost and travel dates) provided.

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?

Though schema coverage is 100%, the description reinforces the core semantic meaning of the 'slug'—it identifies 'one' specific road trip—and describes the purpose of all optional parameters like 'lang' and 'travel_date' in terms of feature delivery (e.g., checking for seasonal passes).

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 purpose is to provide a 'Day-by-day overview' of a specific road trip. It explicitly mentions all the data points included (from, to, km, highlights, cost estimate), making the function highly specific and easy to categorize.

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?

By detailing exactly what information is retrieved (full itinerary, cost, passes, links), it clearly differentiates itself from siblings like 'find_road_trips,' which would likely return a list or abstract summary.

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