vpn-mcp

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

With no annotations provided, the description carries full behavioral disclosure burden. It explains side effects ('Starts local proxy'), conditional return values ('returns payment instructions'), and specific handling requirements ('payment address is returned directly'). Deducted one point only because it doesn't describe error states or idempotency 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?

Four sentences each serving distinct purposes: (1) Core action, (2)_next_step in workflow, (3) Conditional payment flow, (4) Handling constraint. Zero redundancy, front-loaded with the primary action, appropriate density for the complexity.

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, so the description appropriately explains return behavior for both success path (implied by 'After connecting') and the payment edge case ('returns payment instructions'). Could be improved by explicitly describing the successful connection return value format.

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% with the 'node' parameter fully documented as 'Exit node ID (e.g. 'na-1'). Optional.' The description mentions connecting to an 'exit node' providing context but adds no syntax, validation rules, or semantic details beyond what the schema already specifies.

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 ('Connect') with a specific resource ('VPN exit node') and immediately distinguishes from siblings by stating it 'Starts local proxy' and referencing the follow-up tool 'vpn_fetch' 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 explicit sequencing guidance ('After connecting, use vpn_fetch'), states the precondition for activation/payment flow ('If the account is not yet activated'), and specifies handling constraints ('Do NOT open a browser'), clearly mapping the tool's place in the sibling tool ecosystem.

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