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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, but the description adds important behavioral context: no money moves, end_of_period never refunds, immediate cancellations are irreversible, and a 409 nothing_to_undo error is typical. These details go well beyond the annotations and are consistent with them.

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 tightly structured and front-loads the core action before consequences, constraints, prerequisite state, and error handling. Every sentence adds distinct value, and there is no filler or repetition.

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 tool with clear annotations and a fully documented schema, the description supplies the remaining context an agent needs: applicability conditions, financial behavior, irreversibility of the alternative, required state, and expected error. No output schema is present, and return values are not needed for correct invocation.

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 the single optional service_id parameter is fully documented in the schema. The description does not add syntax, format, or behavioral detail about service_id beyond what the schema already provides, so the baseline of 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?

Clearly states the action: undo a scheduled cancellation for a VPS whose cancellation type is end_of_period, keeping the server active. It distinguishes scheduled cancellations from immediate ones, which is the key boundary. An agent can identify the tool's purpose and scope without opening the 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?

Specifies exactly when the tool applies (scheduled end_of_period cancellation), when it does not (immediate cancellation cannot be undone), and what state to check first via get_vps_status. It also names a required condition and a typical error, leaving little to inference.

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