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

Annotations already declare readOnlyHint=false, destructiveHint=true and openWorldHint=false, so the mutation and safety profile is covered. The description adds scope (the connected user's garage) and one boundary (no deletes), but is silent on the critical behavior for a 21-param update: whether omitted fields are preserved or cleared, and what permissions are needed. The 'delete not supported' note sits somewhat at odds with the destructiveHint=true annotation, but does not outright contradict it.

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?

Two short sentences with zero waste; the core action is front-loaded and the constraint follows immediately. Nothing redundant or padded.

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?

An output schema exists, so return values need not be explained, but for a 21-parameter mutation with a pseudo-optimistic-concurrency parameter the description omits the single most important behavioral fact: whether this is a partial merge or a full replace. With annotations covering only the safety profile, that gap is material.

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 5% (just expectedUpdatedAt), so the description is expected to compensate, and it does not: it mentions no field, no merge/patch semantics, and no guidance on the enum-bearing fields like fuel, purpose, aspiration or transmissionType. Only the barest implication that an existing vehicle must be identified is present.

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 and resource ('Edits an existing vehicle') and scopes it to the user's TuneWorks garage. The phrase 'existing' plus 'Deletes are not supported' implicitly separates it from create_vehicle and archive_vehicle/delete-style siblings, though no sibling is named explicitly.

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?

Usage is implied by 'edits an existing vehicle' and the note that deletes are unsupported rules out one adjacent operation. However, it never says when to use this versus update_vehicle_modification (for modifications) or when to prefer archive_vehicle, leaving the agent to infer routing from tool names.

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