Vehicle health and maintenance

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

Annotations already indicate the tool is read-only, idempotent, and non-destructive, so the description does not need to restate those. The description adds useful behavioral boundaries: the data covers current alerts and past service history, but not future maintenance predictions. This helps the agent set expectations about what the tool can and cannot answer.

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 short, front-loaded with the most important data categories, and includes a compact usage note. Every sentence earns its place; there is no repetition 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?

For a parameterless, read-only tool with an output schema present, the description covers the main response contents and the key limitation about maintenance deadlines. The agent has enough context to select and invoke this tool correctly without additional explanation.

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 parameter-level semantics are not needed. The description still adds value by enumerating what health-related data the response will contain, which is enough for an agent to know what to expect.

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 identifies the tool as providing warning lights, oil indicators, recent notifications, and service history, which makes the resource scope clear. It does not explicitly state a verb like 'retrieves' or 'gets', but the title and sibling context make the operation obvious. It is distinguishable from siblings like toyota_get_status and toyota_get_vehicle_info by its health/maintenance focus.

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 'Use for' section gives concrete, natural-language triggers: any alerts on the car and when it was last serviced. It also includes an important exclusion by noting that Toyota exposes service history, not upcoming maintenance deadlines. It does not name specific sibling alternatives, but the usage guidance is otherwise clear.

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