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

With no annotations provided, the description carries the full burden. It adds useful behavioral context: authentication is required and the operation is read-only in intent ('Get detailed information'). However, it does not disclose return format, whether the response includes any nested pricing structures, or any rate-limit/error behavior.

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?

Three sentences with no filler. The core purpose is first, followed by auth/required-parameter guidance, then a clear routing note. Every sentence earns its place.

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 two-parameter read tool with no output schema, the description covers the essential call context: what it does, auth requirement, required parameter, and when to use a sibling. It does not describe the response shape, which might matter for parsing, but the low complexity keeps this from being a major gap.

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 50%; packageId has no schema description, but the description supplies its meaning and requiredness: 'Required: packageId (string)'. It also explains the anonymous alternative. sessionKey is already documented in the schema, so the description adds value where the schema is weakest.

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 detailed information'), a specific resource ('specific VPS package'), and a distinguishing scope ('including all pricing tiers'). It clearly differentiates from siblings: listVpsPackages lists packages, getVpsInstanceDetails targets instances, while this targets package 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?

It explicitly says authentication is required, names the required parameter packageId, and provides a direct alternative: 'For anonymous browsing use listVpsPackages'. This tells an agent exactly when to use this tool and when to route to a sibling.

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