OPNSense MCP Server

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 states the action ('Find') but doesn't describe what 'devices' entails (e.g., network endpoints, hosts), the return format, whether it's a read-only operation, or any limitations like rate limits or authentication needs. The description is minimal and lacks critical behavioral context for a tool that queries network data.

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: 'Find devices on specific VLAN'. It is appropriately sized and front-loaded, directly stating the tool's purpose without unnecessary elaboration, making it easy to parse quickly.

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 the tool's complexity (querying network devices), lack of annotations, and no output schema, the description is incomplete. It doesn't explain what 'devices' means, the return format, or any behavioral traits like safety or performance. For a network discovery tool with no structured support, more context is needed to guide effective use.

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?

The input schema has 100% description coverage, with 'vlanTag' documented as 'VLAN tag number (e.g., "6" for DMZ)'. The description adds no additional parameter semantics beyond what the schema provides, such as format details or examples. With high schema coverage, the baseline score of 3 is appropriate, as the schema does the heavy lifting.

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 'Find devices on specific VLAN' clearly states the verb ('Find') and resource ('devices'), specifying the scope ('on specific VLAN'). It distinguishes from some siblings like 'find_device_by_mac' or 'find_device_by_name' by focusing on VLAN-based discovery, but doesn't explicitly differentiate from 'get_devices_by_interface' which might overlap in network context.

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?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites, such as needing VLANs to be configured, or compare to similar tools like 'get_devices_by_interface' or 'find_device_by_mac'. Usage is implied by the name alone, with no explicit context or exclusions provided.

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