OPNSense MCP Server

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

No annotations are provided, so the description carries full burden. It states the action ('group') but doesn't disclose behavioral traits: it doesn't specify if this is a read-only operation, what data format is returned (e.g., list, dictionary), whether it requires authentication, or any rate limits. For a tool with zero annotation coverage, this is a significant gap in transparency.

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: 'Group devices by network interface.' It's front-loaded with the core action and criterion, with zero wasted words. Every part of the sentence contributes directly to understanding the tool's function.

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 no annotations, no output schema, and zero parameters, the description is minimal. It states what the tool does but lacks completeness: it doesn't explain the return format (e.g., grouped data structure), error conditions, or dependencies. For a tool that likely returns structured data, this leaves the agent with insufficient context to use it effectively.

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 tool has 0 parameters, and schema description coverage is 100%, so no parameter documentation is needed. The description doesn't add parameter details, which is appropriate here. Baseline is 4 for zero parameters, as it avoids unnecessary repetition and focuses on the tool's purpose.

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 'Group devices by network interface' clearly states the verb ('group') and resource ('devices'), specifying the grouping criterion ('by network interface'). It distinguishes from siblings like 'find_device_by_mac' or 'get_guest_devices' by focusing on grouping rather than finding or filtering. However, it doesn't explicitly mention what 'devices' refers to (e.g., network devices, endpoints), leaving some ambiguity.

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 on when to use this tool versus alternatives. It doesn't specify prerequisites (e.g., needing prior interface data from 'get_interfaces'), exclusions (e.g., not for real-time monitoring), or compare to siblings like 'find_devices_on_vlan' for VLAN-based grouping. The description implies usage for grouping but offers no contextual boundaries.

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