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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds behavioral details: snapshot years back to 2019, default year 2026, substring matching for make, and two distinct return formats. This goes beyond annotations, though authentication and rate limits are not mentioned.

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 concise, front-loading the core purpose, then listing example queries and parameter details. Every sentence adds value with no redundancy.

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?

With no output schema, the description adequately explains the two return types (fuel mix with shares or breakdown by dimension) and covers all parameters. It could be more explicit about response structure or pagination, but the examples cover common use cases.

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?

Input schema has 100% description coverage with detailed parameter descriptions. The tool description reinforces this but does not add new semantic meaning beyond what the schema already provides. For example, the group_by parameter description in the schema already explains the options.

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 'measure' and the resource 'electric-vehicle adoption in California'. It provides specific examples of queries it answers, distinguishing it from sibling DMV tools that deal with driver licenses, forms, offices, etc.

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 lists example questions and mentions statewide or ZIP-code scope, giving clear context for when to use the tool. However, it does not explicitly state when not to use it or name alternatives, though the narrowly defined domain makes this less critical.

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