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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds genuinely useful scoping behavior — Rush SR only, not other vehicles, not purchasing questions — which the annotations do not convey. It stops short of describing what the diagnosis output contains, but an output schema exists to cover that.

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?

Three tight sentences, front-loaded with the use case before the exclusions. The embedded example 'such as why won't my Rush SR start' interrupts the opening sentence slightly but costs nothing in clarity or length.

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 read-only two-parameter diagnostic tool with an output schema, the description covers purpose, routing, and domain scope adequately. The only real gap is that the undocumented 'context' parameter is never addressed, though the output schema relieves it of explaining return values.

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 0%, so the description carries the burden, and it only partially compensates. The example 'why won't my Rush SR start' does hint that symptom is free-form natural language, but the 'context' parameter (maxLength 500) is never mentioned, nor is any guidance on what belongs in symptom vs context.

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?

States a specific verb (diagnose) and resource (Rush SR symptom) and rules out the adjacent siblings by naming their domains: service intervals (maintenance_schedule) and step-by-step repair procedures (lookup_procedure). An agent can distinguish this tool from both siblings without opening a schema.

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?

Explicit when-to-use ('why won't my Rush SR start') and two explicit when-not-to-use cases that map directly onto the sibling tools, plus a vehicle-scope exclusion and a 'buying advice' exclusion. Routing is fully determined by the text.

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