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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows it's a safe read operation. The description adds value by specifying the returned fields (investigation number, type, description, latest activity date, NHTSA action number) and scope (active and closed investigations for US vehicles). This provides useful behavioral context 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 only two sentences. The first sentence immediately states the purpose and key input. The second sentence lists the returned fields and coverage. Every word adds value - no filler or repetition.

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?

Given the tool's simplicity (2 params, output schema exists, good annotations), the description is largely complete. It clarifies the source (NHTSA) and the type of records (investigations). Minor omissions like result limits or sorting are not critical for this straightforward search tool.

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% - both parameters have descriptions. The description mentions 'by manufacturer and model', which aligns with the schema but adds no additional meaning, formats, or constraints beyond what the schema provides. Baseline score of 3 is appropriate.

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 states the verb 'Search', the resource 'NHTSA defect investigation records', and the input parameters 'by manufacturer and model'. The title 'Defect Investigations' reinforces the purpose. It distinguishes from sibling tools like vehicle.safety.complaints by specifying investigations with types (preliminary/engineering analysis).

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 does not provide guidance on when to use this tool versus alternatives such as vehicle.safety.complaints or vehicle.safety.recalls. It lacks when-to-use or when-not-to-use instructions, leaving the agent to infer from the tool name and description alone.

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