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

Annotations already indicate read-only, open-world, and idempotent behavior. The description adds valuable context: published endpoints use cached data (zero Mapbox calls), novel pairs use a capped live route or degrade to published alternatives. This goes beyond annotations by explaining caching and graceful degradation. No contradictions.

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?

At two sentences, the description is concise, but it front-loads coverage information rather than directly stating what the tool does. The licensing sentence could be moved elsewhere. Structure could better emphasize the primary action.

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 (4 parameters, no output schema), the description lacks essential context: parameter semantics, input format expectations (e.g., city names vs coordinates), and what the returned data looks like. Coverage and licensing details are helpful but insufficient.

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 0%, and the description provides no explanation for any of the four parameters ('from', 'to', 'hideKinds', 'detourBudgetMinutes'). The agent gets no help understanding the meaning or format of inputs.

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 title 'Plan a detour-aware U.S. drive' indicates the core function, but the description does not explicitly state that it computes a route between 'from' and 'to' locations. It focuses on coverage and licensing, making the purpose somewhat vague. It does not clearly distinguish from sibling tools like 'get_drive' or 'list_drives'.

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 mentions geographic coverage and usage restrictions (individual-assistant use with attribution), but does not provide guidance on when to use this tool versus alternatives. No exclusion criteria or alternative tool names are given.

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