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

With no annotations, the description carries the behavioral disclosure burden. It does disclose three return paths (efficiency, NEEDS_IDENTITY, NO_MATCH), which is helpful, but it does not clarify what 'safely selected' means, what input conditions trigger each path, or any side effects or data source details.

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 a single concise sentence that front-loads the primary behavior and conditional outcomes. It has no filler, though the terse phrasing leaves key terms undefined.

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 tool with eight optional parameters, no output schema, and no annotations, the description is incomplete. It explains return conditions but not invocation prerequisites, required parameter combinations, or how NEEDS_IDENTITY differs from NO_MATCH, leaving an agent uncertain about correct usage.

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 description coverage is only 13% with eight parameters, and the description adds no information about how any parameter contributes to selecting the EPA candidate. The agent is left to guess from property names like vin, make, trim, and engine, which is insufficient given the low schema coverage.

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 states a specific verb and resource: 'Return EPA efficiency'. It also distinguishes this tool from siblings by focusing on EPA efficiency data, with no overlap with fitment, safety, specs, or vehicle resolution.

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 description gives conditional guidance: only return efficiency when the EPA candidate is safely selected, otherwise return NEEDS_IDENTITY or NO_MATCH. However, it does not explicitly name when to prefer this tool over siblings or state any prerequisites such as calling resolve_vehicle first.

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