OPNSense MCP Server

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

With no annotations provided, the description carries full burden but only states 'Create' without disclosing behavioral traits. It doesn't mention whether this is a mutating operation, what permissions are required, whether ACLs have specific constraints, what happens on failure, or what the expected response format is.

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?

The description is a single, efficient sentence with zero waste. It's appropriately sized for a tool with good schema coverage and gets straight to the point without unnecessary elaboration.

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 creation tool with no annotations and no output schema, the description is insufficient. It doesn't explain what happens after creation, whether the ACL becomes active immediately, what validation occurs, or what format the result takes. The context signals show this is a 3-parameter tool with no behavioral guidance.

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 100%, so the schema already documents all three parameters. The description doesn't add any meaning beyond what the schema provides about parameters, nor does it explain relationships between parameters (e.g., that the frontend must exist, ACL naming conventions, or expression syntax).

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 clearly states the action ('Create') and resource ('an ACL for HAProxy frontend'), providing specific verb+resource pairing. However, it doesn't distinguish this tool from sibling HAProxy tools like 'haproxy_action_create' or 'haproxy_backend_create' beyond the ACL focus.

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?

No guidance is provided about when to use this tool versus alternatives. The description doesn't mention prerequisites, related tools like 'haproxy_frontend_create' that might need to exist first, or when to choose this over other ACL-related operations that might exist in the system.

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