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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the auth requirement ('Requires authentication') and the downstream cost/ownership semantics, which the annotations do not cover — useful added context beyond structured fields.

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 the verb+resource and three tightly scoped sentences where each clause carries meaning. The redundant 'listMyVpsInstances:' name prefix is the only wasted token.

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?

No output schema exists, and the description supplies the most important return detail (the instanceId is the key consumable output) plus the auth requirement. It does not mention return shape beyond instanceId or pagination, but for a simple single-param read tool this is largely sufficient.

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% and the single optional sessionKey parameter is fully documented in the schema, including when to pass vs. omit it. The description adds nothing about the parameter, so the baseline 3 for a well-covered schema 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+resource with scope: 'List all VPS instances owned by the authenticated user.' The scoping phrase ('owned by the authenticated user') implicitly distinguishes it from countMyVpsInstances and getVpsInstanceDetails, and the cross-reference to osirAppDeployToVps anchors its role in the workflow.

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?

Provides a concrete use case: the instanceId from this list is the input osirAppDeployToVps needs to deploy to an already-owned server 'at no cost.' This tells the agent when to reach for it, but names no explicit alternative (e.g., countMyVpsInstances, getVpsInstanceDetails) or when-not conditions.

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