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

Annotations already give idempotentHint=true and destructiveHint=false, and the description reinforces this with 'Nothing in the mailbox changes'. It also adds new context about the 15-minute expiration and that cancellation 'records the decision', which goes beyond what the annotations state.

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?

The description is only a few sentences, with the essential action and consequence front-loaded. Every sentence provides a relevant detail: the decline action, the input scope, the non-mutating nature, and the expiry alternative. No filler or extraneous content.

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 that the tool has a single parameter, an output schema, and annotations covering idempotency and safety, the description provides enough to call the tool correctly. It covers what action is taken, what won't change, and how the cancellation is recorded, leaving no critical gap for this simple use case.

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% and the only parameter, plan_id, is already fully described as a UUID returned from a bulk preview. The description only says 'Takes only the plan_id' which does not add new semantic meaning beyond the schema.

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 uses the specific verb 'Decline' and names the resource ('a previewed bulk delete or move'), then adds the consequence 'so it can never run' and distinguishes itself from bulk execution. It also clarifies the single input with 'Takes only the plan_id', which fully separates this from bulk_execute.

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?

The description provides clear context: use it to decline a preview operation before it runs. It also explains an alternative, 'would also expire on its own after 15 minutes', implying the choice to cancel now or do nothing. However, it does not name a sibling like bulk_execute explicitly, so it lacks the exclusions of a full 5.

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