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

With no annotations, the description carries the full burden and does well: it discloses that ranges are estimates that must be presented as approximate, and that 'Pro only' means the job isn't realistic DIY. It doesn't detail authentication, rate limits, or output format, but the output schema exists to cover return values.

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?

Four sentences, each earning its place: usage trigger, mileage instruction, presentation guidance, and output framing for 'Pro only'. Front-loaded with the usage condition.

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 an output schema exists, the description needn't explain return values. It covers when to use, mileage handling, and output presentation. It could mention prerequisites (e.g., needing resolved vehicle identifiers), though the schema descriptions reference 'from resolve_vehicle' which implies this. Nearly complete.

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 schema already documents all parameters including the mileage constraint (0-1,000,000). The description adds 'Pass mileage when known,' which reiterates the schema's 'when the user mentioned it' – marginal added value. Baseline 3 is appropriate when the schema does the heavy lifting.

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 title and description clearly establish this as a maintenance schedule tool with Dealer/Shop/DIY price ranges and service intervals. It states a specific resource (maintenance schedules) but doesn't explicitly differentiate from siblings like get_known_issues or get_recalls, though the distinct purpose is inferable.

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?

Explicitly states when to use ('when the user asks about service intervals, what's due, or what a service should cost') and provides concrete conditions for mileage input ('Pass mileage when known'). Also includes specific guidance on handling 'Pro only' jobs, which routes the agent's response behavior.

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