Rollback snapshot

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

Goes well beyond the destructiveHint=true annotation by specifying the exact consequence ('disk state after the snapshot is lost'), the confirmation requirement, the required authorization scope, and the billing/expiry behavior of snapshots. This is the kind of operational context an agent needs before invoking a destructive write.

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?

Front-loaded with purpose and the destructive warning, which is the right ordering. The trailing tips about taking snapshots before risky changes and deleting them to avoid billing, while genuinely useful, drift into the lifecycle of create_snapshot/delete_snapshot rather than this tool.

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 no output schema and only two fully-documented required parameters, the description supplies the missing pieces an agent needs: irreversibility of the operation, confirmation, and auth scope. Nothing essential is absent, though it doesn't state what the call returns (e.g., an async operation/event handle).

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%: orderNo's format and snapname's origin ('from list_snapshots') are already fully documented in the schema. The description adds no parameter-level meaning beyond that, 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 precise verb+resource ('Roll a Cloud VPS (KVM/VDS) service back to a disk snapshot') and qualifies the scope as KVM/VDS, which implicitly distinguishes it from the sibling rollback_firecracker_snapshot. An agent can identify the operation 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?

Gives clear context for use, a confirmation prerequisite ('Confirm with the user before calling'), and a precondition (services:manage + full-access API key). It does not explicitly name alternatives such as rollback_firecracker_snapshot or point to list_snapshots for obtaining snapname, so routing is implied rather than spelled out.

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