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. 'Create a new firewall rule' implies a write/mutation operation but doesn't specify whether this requires admin permissions, whether rules take effect immediately, if there are rate limits, or what happens on failure. For a security-critical mutation tool, this is insufficient behavioral context.

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 maximally concise at just four words, front-loading the essential information with zero wasted words. Every element earns its place, making it easy to parse while conveying the core purpose.

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 firewall rule creation tool with 10 parameters, no annotations, and no output schema, the description is incomplete. It doesn't address security implications, permission requirements, typical workflows, or what the tool returns. The agent must rely entirely on the input schema without higher-level guidance about this critical infrastructure operation.

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 description adds no parameter information beyond what's already in the schema, which has 100% coverage with detailed descriptions for all 10 parameters. The baseline score of 3 reflects adequate parameter documentation through the schema alone, though the description could have provided higher-level context about parameter relationships or constraints.

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 ('firewall rule'), making the purpose immediately understandable. However, it doesn't distinguish this tool from its sibling 'create_firewall_preset' or explain how it differs from 'update_firewall_rule', which prevents a perfect score.

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 like 'create_firewall_preset', 'update_firewall_rule', or 'delete_firewall_rule'. It also doesn't mention prerequisites, dependencies, or typical use cases for firewall rule creation.

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