vpn-mcp

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

With no annotations provided, the description carries full disclosure burden effectively. It specifies return value (TON USDT address), cost (1 USDT), payment method (Tonkeeper, TonHub), auto-detection behavior, and critical constraint (no browser needed). Lacks only error-handling or idempotency details.

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?

Five sentences covering: purpose, return value, user instructions, technical constraints, and next-step workflow. Each sentence earns its place with zero redundancy. Front-loaded with purpose, logically sequenced through the payment flow.

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?

Despite lacking output schema and annotations, the description compensates by detailing exact return content (payment address, instructions) and complete workflow through to connection. No critical gaps for a payment-activation tool, though failure modes could enhance it further.

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?

Input schema contains zero parameters. Per calibration rules, 0 params warrants baseline 4. The tool requires no arguments and the description correctly implies this is a simple activation trigger.

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 opens with the specific verb 'Activate' and resource 'VPN account', clearly defining the scope. It distinguishes from siblings (vpn_connect, vpn_status) by clarifying this initiates payment/activation rather than connection or status checking.

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?

Explicitly prescribes workflow: 'After the user pays, call vpn_status() to check, then vpn_connect() to start.' Includes negative constraint 'Do NOT open a browser' and specifies exact prerequisite (user must send 1 USDT via TON wallet), providing clear when-to-use and when-not-to-use guidance.

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