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

Annotations already declare readOnlyHint=true and openWorldHint=false, establishing this as a safe read operation. The description adds useful context by noting it returns capacity and base rates, which goes beyond the annotation. No contradiction exists.

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 just two sentences, front-loaded with the action and resource. Every word earns its place, with no redundant information or filler.

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 simplicity (0 parameters, read-only, clear annotations), the description is largely complete. It conveys the main purpose, usage context, and the key data returned (capacity, base rates). Minor omissions like ordering or availability semantics are not critical at this complexity level.

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 tool has zero parameters, so the description does not need to explain parameter syntax or meaning. The baseline of 4 applies per the rubric for parameterless tools, and no parameter-related gaps exist.

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 it 'List all available vehicles with capacity and base rates.' The verb 'List' plus the resource 'vehicles' and specific attributes clearly distinguish it from sibling tools like book_ride, get_quote, and resolve_flight.

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 'Use this to help the customer choose the right vehicle for their trip,' providing clear when-to-use context. It does not explicitly mention alternatives to avoid, but the sibling tools are all different operations, making the intended use unambiguous.

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