OPNSense MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While 'control' implies a mutation operation, it doesn't specify whether this requires elevated privileges, what happens on failure (e.g., service state after a failed restart), or if actions like 'stop' are destructive to active connections. The description lacks critical behavioral context for a service control tool.

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 extremely concise (one short phrase) and front-loaded with all necessary core information. Every word earns its place—there's no redundancy or unnecessary elaboration. It efficiently communicates the tool's scope in minimal text.

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 complexity of service control (a mutation operation with potential side effects), the description is incomplete. With no annotations and no output schema, it fails to address critical aspects like required permissions, error behavior, or what 'status' returns. For a tool that can stop/restart a critical service, this lack of context is a significant gap.

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%, with the single parameter 'action' fully documented in the schema (including enum values and description). The description adds no additional parameter semantics beyond what's already in the structured schema, so it meets the baseline of 3 for high schema coverage without adding value.

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 tool's purpose with specific verbs ('start, stop, restart, reload') and identifies the resource ('HAProxy service'). It distinguishes itself from sibling tools that focus on HAProxy configuration (e.g., haproxy_backend_create) by targeting service control operations. However, it doesn't explicitly differentiate from potential non-HAProxy service control tools in the broader set.

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 (e.g., HAProxy must be installed), when to choose 'reload' over 'restart', or how it differs from other service management tools that might exist in the environment. Usage is implied but not explicitly stated.

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