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signalgrid_kernel_extensions

Read-onlyIdempotent

Identify loaded third-party kernel extensions on macOS to evaluate device trust signals. Uses kmutil or kextstat to list non-Apple kexts.

Instructions

Loaded kernel extensions, with third-party (non-Apple) kexts singled out.

Modern macOS strongly discourages kexts; any third-party kext is a significant trust signal (legacy security tools, virtualization, or something worse). Tries kmutil showloaded first, falls back to kextstat.

Returns: dict with keys: third_party (list[str] of loaded non-Apple kext lines, ideally empty), raw (full loader output), source ('kmutil' or 'kextstat'), or {"error": str} if neither tool ran.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "signalgrid_kernel_extensions"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.2Aug 12, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Beyond the read-only/idempotent annotations, the description discloses fallback behavior (tries kmutil, falls back to kextstat) and defines the exact return structure including error cases. This adds meaningful transparency about how the tool behaves in practice.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise and well-structured: a clear first sentence, relevant security context, fallback detail, and a formatted Returns section. Every sentence serves a distinct purpose without unnecessary fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (no parameters) and the presence of an output schema, the description fully covers the behavior, return format, and error handling. It provides all necessary context for an agent to invoke the tool and interpret results confidently.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the description cannot add parameter-level meaning. The baseline for 0 params is 4; the description appropriately focuses on the output contract instead, even though it's not explicitly about parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: retrieving loaded kernel extensions and singling out third-party kexts. It uses a specific verb ('Loaded') and resource ('kernel extensions'), and the emphasis on third-party kexts distinguishes it from siblings like signalgrid_system_extensions.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides strong context for when this tool is relevant: checking for third-party kexts as a trust signal in macOS security assessments. It does not explicitly name alternatives or state when not to use it, but the context is clear and actionable.

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