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

With no annotations, the description carries the full burden. It discloses 'Requires authentication' and the required instanceId, but does not describe potential errors, permission requirements beyond authentication, or whether the call has side effects. For a read-only 'get' tool this is minimally adequate.

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 short sentences with no fluff. It front-loads the core purpose and then adds the necessary authentication and required-parameter note, making it easy to parse quickly.

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 low-complexity read tool with one required parameter, the description plus schema is reasonably complete. It states the purpose, the required parameter, and authentication need; the optional sessionKey is already documented in the schema. Some details about response structure or error cases are absent, but nothing critical blocks 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 only 50%, and the description's 'Required: instanceId (string)' merely repeats the schema rather than adding semantic meaning. It does not explain what an instanceId looks like, how to obtain it, or clarify the optional sessionKey, leaving the agent with a partial understanding of the parameters.

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 states a specific verb ('Get'), a clear resource ('detailed information about a specific VPS instance'), and a distinguishing aspect ('including resource usage'). This separates it from siblings like listMyVpsInstances and getVpsPackageDetails, which cover listing and package-level details.

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 implies when to use the tool: when you need detailed information and resource usage for one specific VPS instance. However, it does not explicitly compare with alternatives or state when not to use it, leaving the routing partially implicit.

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