vpn-mcp

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the auto-invocation relationship with vpn_connect, but omits critical safety details for an installation tool: whether it requires elevated privileges, if it is idempotent/safe to rerun, or where binaries are installed.

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?

Two sentences, zero waste. First sentence defines the operation, second defines the orchestration relationship. Every word earns its place; no redundancy or tangential information.

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 zero-parameter utility with no output schema, the description adequately covers the core function and sibling relationship. Minor gap: lacks permission/safety warnings typical for OS-level binary installation, but sufficient for an agent to select and invoke correctly.

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 (empty object). According to evaluation rules, zero parameters establishes a baseline score of 4. The description appropriately requires no parameter clarification.

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?

Description clearly specifies the action ('Download and install') and target ('VPN binary for the current OS'). The second sentence explicitly distinguishes this tool from sibling vpn_connect by stating it is 'Called automatically by vpn_connect if needed,' clarifying this is a prerequisite/setup tool rather than the connection entry point.

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 clear contextual guidance that vpn_connect automatically invokes this tool when needed, implying vpn_connect is the preferred entry point for users. However, it lacks explicit 'when to use manually' vs 'when to avoid' guidance beyond the automatic invocation note.

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