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

Annotations already declare the mutating, non-idempotent, non-destructive profile, so the description only needs to add context. It does add the preconditioning coupling hint, but omits key behavior: whether disabling clears the stored time, whether the vehicle must be awake/online, and whether preconditioning stays on when the feature is turned off.

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?

Two short sentences with no wasted words and the action front-loaded. However, the parenthetical '(minutes past midnight)' is syntactically attached to 'scheduled departure' rather than to the departure_time parameter, creating minor ambiguity about what it modifies.

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 4-parameter mutation with no output schema, the definition leaves too much open: no mention of success/failure semantics, no handling of the optional vin, and no light on the required/optional interaction between 'enable' and 'departure_time'. Annotations cover safety but not the operational details an agent needs.

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 coverage is only 25%, with just 'departure_time' documented as 'Minutes after midnight' — and the description merely repeats that same wording. The optional 'vin', the 'enable' toggle, and 'preconditioning_enabled' get no explanation, and it never clarifies what happens if 'enable' is true but no departure_time is supplied.

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 names a specific verb pair and resource ('Enables or disables scheduled departure'), which is clear enough to distinguish this from siblings like set_charge or set_climate. It lacks any explicit contrast with those neighbouring setting tools, so it falls short of a 5.

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?

There is no when-to-use, when-not-to-use, or prerequisite guidance at all. The agent is left to infer that this applies to vehicles and that preconditioning is related but configured elsewhere.

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