List VPN interfaces

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

With readOnlyHint=true and openWorldHint=false annotations covering the safety profile, the description adds genuine value by disclosing that 'Secrets are always redacted.' This tells the agent the output is safe to relay and that no secret material will ever appear, which is meaningful beyond what annotations convey. The 'compact status' qualifier also sets output-depth expectations.

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 brief sentences with zero filler. Purpose is front-loaded first, followed by the redaction caveat. Tight and efficient, though it could arguably merit a 5 for being maximally lean.

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?

Given this is a low-complexity tool with no parameters, no output schema, and read-only annotations, the description covers the essentials: what is returned (status of interfaces and peers) and the key behavioral constraint (secret redaction). The only minor gap is not detailing what 'status' fields are included, but this is acceptable for a simple read-only listing tool.

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?

With zero parameters, the baseline is 4 per the rubric. The description appropriately avoids fabricating parameter meaning since there is nothing to document.

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 clear verb and resource: list 'compact status for VPN interfaces and WireGuard peers.' Mentioning WireGuard peers adds specificity that partially distinguishes it from siblings like get_vpn, but the description never explicitly differentiates the list orientation from the single-item get_vpn sibling.

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?

Usage context is only implied through naming conventions — list_vpn vs get_vpn suggests a list-vs-detail split, and list_interfaces indicates a broader/alternative listing tool. However, no explicit when-to-use or when-not-to-use guidance, alternatives, or exclusions are stated.

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