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

Beyond the annotations' general mutation and safety hints, the description identifies the specific vehicle state being changed and confirms that the tool both starts and stops preconditioning. It does not explain command prerequisites, how temperature settings affect the operation, or what happens when stopping with temperatures supplied.

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 single sentence is front-loaded and contains no unnecessary wording. However, the slash construction is slightly imprecise, and the extreme brevity leaves little room for operationally important parameter guidance.

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?

For a four-parameter vehicle mutation with no parameter documentation or output schema, the basic purpose alone is not enough to support reliable invocation. Important gaps include VIN selection, temperature behavior and constraints, the relationship between on and the temperature fields, and any wake or connectivity prerequisites.

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?

With 0% schema description coverage, the description only indirectly explains the required on parameter through 'starts or stops.' It adds no explicit meaning for vin, driver_temp_c, or passenger_temp_c, including vehicle selection, valid temperature ranges, defaults, or interactions with on.

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 actions and resource: starting or stopping cabin climate/preconditioning. It does not explicitly differentiate this tool from related siblings such as remote_start, set_seat_heater, or set_scheduled_departure.

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?

Starting or stopping preconditioning gives an implied use case, including both activation and deactivation. There is no guidance on when temperature arguments apply, whether the vehicle must be awake, or when another climate-related sibling would be preferable.

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