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

Beyond annotations (readOnlyHint=false, destructiveHint=false), the description reveals that this is a staging operation, not the final commit, and that it affects billing. It also states the authentication requirement. This adds meaningful behavioral context beyond what annotations alone provide.

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 two sentences with no fluff. It front-loads the purpose and then gives the essential usage pattern. Every sentence 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?

For a mutation with a follow-up action, the description explains the entire flow: what it does, what it returns (actionId), and how to proceed. It doesn't discuss error handling or side effects, but the essential information an agent needs to correctly invoke and follow through is present.

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%, with each parameter clearly described (instanceId from listMyVpsInstances, paymentTerm enum values, sessionKey conditions). The description adds no additional parameter-specific information, so the schema carries the burden. Baseline 3 is appropriate.

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 clearly states the verb 'change' and the resource 'payment term for a VPS instance', distinguishing it from related sibling tools like getVpsInstanceDetails or listMyVpsInstances. It also notes the billing implication, making the purpose unambiguous.

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 explicitly outlines the required two-step flow: stage the change, get an actionId, then call executeConfirmedAction if the user approves. It also mentions the authentication requirement. While it doesn't contrast with alternative tools, the usage pattern is clear and actionable.

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