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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds real context beyond that: the revocation takes effect immediately ('at once') and changes how car_key_check subsequently reports the key. It does not say whether the operation is reversible or what happens on a re-revoke, which keeps it below 5.

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, front-loaded with the action and followed by the consequence. Nothing is 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?

For a 3-required-parameter destructive tool with no output schema, the description covers purpose and post-condition, and annotations cover the risk profile. It leaves out permission/auth requirements and the idempotent re-revoke behavior, which an agent would want before calling a destructive operation.

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 100% and every parameter documents its own format (ck_..., car_.../VIN, carkey_... from car_register). The description adds no parameter-level meaning, so the baseline of 3 applies.

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 gives a specific verb and resource ('Revoke a digital key'), immediately distinguishing it from car_key_issue and car_key_check. It also states the observable end state. It stops short of naming a sibling as the alternative, which keeps it from a 5.

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 the imperative 'Revoke a digital key at once', and the mention of car_key_check's later answers hints that this is the terminal operation on a key. There is no explicit when-to-use/when-not-to-use guidance and no stated prerequisites, such as needing the owner_key from car_register.

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