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

Annotations declare destructiveHint=true and idempotentHint=false, which alone would make an agent cautious. The description adds genuinely new behavioral context: the undo covers one change regardless of who made it, the undo is itself reversible, and the safety property that nothing saved after the undone change is lost. That reframes a 'destructive' call as a safe, recoverable one.

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 tight sentences, front-loaded with the action and the trigger. The third sentence ('Only the most recent change can be undone, so nothing saved after it is lost') partially restates the scope already given in sentence one, a small redundancy, but every sentence otherwise earns its place.

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 and annotations cover the safety profile, so the description only needs to supply intent, trigger, constraints and reversibility — all present. An agent can call this correctly and set expectations about failure modes without further information.

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%, so writer, changeId and workspace are already documented with their fallback semantics ('me', personal account, refusal if stale). The description mostly restates the changeId staleness rule rather than adding syntax or format detail, so the baseline 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?

States a specific verb (undo) and resource (the most recent change to the writer's voice profile) with precise scope. It is clearly distinguishable from siblings like update_voice_profile, list_voice_changes and save_voice_preference without opening any 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?

Gives an explicit trigger ('when the writer asks you to'), an explicit constraint ('Only the most recent change can be undone'), and routes to the alternative tool list_voice_changes for obtaining a changeId. The refusal condition ('only if it is still the most recent') tells the agent when this call will fail.

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