Vehicle identity and capabilities

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds useful behavioral context by warning that capability flags are indicative only and pointing to remote_capabilities.note, which is value beyond the annotations.

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 compact and front-loaded: a concrete field list, then question-style use cases, then a one-line caveat. Every sentence contributes actionable information, with no repetition of the schema or annotations.

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 zero-parameter read-only tool with an output schema and strong annotations, this description is complete. It explains what data is returned, when to use it, and flags an important caveat about capability semantics.

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?

There are no parameters and schema description coverage is 100%, so there is no semantic burden on the description. The baseline for zero-parameter tools is appropriate here.

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 concrete fields (model, year, plate, colour, first-use date, subscriptions, remote capabilities) and frames the purpose as answering specific questions such as 'what car is this?' and 'can it be locked remotely?'. This clearly distinguishes vehicle identity/capabilities from sibling tools like energy, status, odometer, or location.

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 explicit question-based scenarios for when this tool is appropriate. It does not state when not to use it or name an alternative tool, but the context is clear enough for an agent to route correctly.

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