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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds useful behavioral context by stating the authentication requirement and clarifying that the anonymous browsing path is served by listVpsPackages. No contradiction with annotations.

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 filler. It front-loads the core purpose, then states the auth requirement and the alternative tool, all in a compact and easily parseable format.

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 simple read-only detail tool with full schema coverage, the description provides the essential context: purpose, auth requirement, and when to use the sibling listVpsPackages tool. The only minor gap is that no expected response shape is described beyond pricing tiers, but no output schema exists and this is unlikely to block 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%, so both packageId and sessionKey are well documented in the schema itself. The description does not add additional parameter-level meaning, but it does not need to because the schema already carries the parameter semantics.

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 uses a specific verb ('Get detailed information') and a specific resource ('a specific VPS package') and explicitly mentions pricing tiers. It also distinguishes itself from listVpsPackages, making the tool's unique purpose clear without requiring schema inspection.

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 states that authentication is required and directs anonymous users to listVpsPackages, which already provides per-term pricing. This gives the agent a clear decision rule for selecting this tool versus the sibling tool.

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