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

Annotations already declare destructiveHint=true and idempotentHint=true, so the bar is lower, yet the description still adds real value: what the cancellation achieves operationally (stops boxes and renewals) and that it is reversible via reactivate. It does not mention permission requirements or any rate/limit behavior, which keeps it short of a 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?

A single front-loaded paragraph that opens with 'WRITE:' so the mutation type is the first thing read, then layers disambiguation, prerequisite, and recovery in descending priority. Every sentence earns its place with no filler.

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?

With annotations covering the safety profile and a full-coverage schema, the description fills the remaining gaps an agent needs: what the write does to the customer, how it differs from the similarly named tool, the confirm gate, and reversibility. No output schema is needed since the description does not promise a return shape.

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 all three parameters are already documented in the schema, including the confirm=true constraint and the log_note log purpose. The description restates the confirm requirement without adding format, bounds, or semantics beyond what the schema provides, so 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 and resource ('cancel a subscriber's subscription in Cratejoy') and immediately scopes it against a confusingly similar sibling ('NOT this server's Pro plan'). The agent can distinguish this from cratejoy_reactivate_subscription and the Pro-plan cancel tool 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?

Explicitly names the alternative tool for the Pro-plan case and the condition that selects it, plus states the prerequisite ('Requires confirm=true') and the recovery path (cratejoy_reactivate_subscription). Nothing about when to use or not use this tool is left to inference.

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