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

With no annotations, the description carries the full behavioral burden. The word 'typically' hints that the answer is generic rather than VIN-specific, which is mildly useful, but there is no disclosure of what the response contains, whether it is static reference content, or any auth/caveat information.

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?

A single front-loaded sentence with the action verb first and zero filler. Every word earns its place.

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 one-parameter informational lookup with no output schema and no annotations, the description is minimal but nearly sufficient to call the tool. It omits any statement about the nature or scope of the returned explanation, leaving an agent slightly under-informed about what it will get back.

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% and the enum fully documents the allowed values ('A' or 'B'). The description repeats that same A/B distinction without adding format or semantic detail beyond the schema, so the baseline 3 applies.

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 gives a specific verb+resource pair: 'Explain' + 'Mercedes-Benz Service A or Service B.' It's clearly distinct from siblings like get_next_service (scheduling) and warning_light_info (dash alerts), though it doesn't explicitly state that differentiation in the text.

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 guidance on when to invoke this versus get_next_service or warning_light_info, and no prerequisites or exclusions are stated. Usage must be inferred entirely from the tool name and description.

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