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

No annotations are provided, so the description carries the full burden. It usefully signals that content is 'general' and limited to 'common' lights, implying a static knowledge base rather than live vehicle diagnostics, but it says nothing about output format, coverage limits, or failure modes.

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, front-loaded with the resource and immediately followed by the mode-switching instruction. Zero 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 single-optional-parameter, no-output-schema lookup tool with no annotations, the description covers both operating modes and the scope of coverage. The only gap is the shape/format of the returned guidance, which an agent could reasonably want.

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 100%, so the baseline is 3, but the description adds the non-obvious meaning of omitting 'light' entirely (returns the list of covered lights). That is semantics the schema does not express, since 'light' is not marked required.

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?

States a specific resource (Mercedes-Benz warning lights and messages) and the two modes it operates in (lookup vs. list). It is clearly distinguishable from the sibling service-scheduling and specialist-finding tools, though it never names them explicitly.

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?

'Omit light to list those covered' tells the agent how to trigger list mode, which is real usage guidance. However, it never says when to prefer this tool over the potentially overlapping explain_service, nor when-not to use it (e.g., for actual diagnostics or a specific fault code lookup).

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