gmod-mcp

run_lua

Run arbitrary Lua code on a Garry's Mod server and retrieve the result. Requires explicit confirmation for security.

Instructions

GUARDED. Runs arbitrary Lua server-side (RunString) and returns the resulting value. Requires confirm:true. Audited.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "code": "<code>"
    },
    "name": "run_lua"
  }
}

Input Schema

Name	Required	Description	Default
`code`	Yes
`confirm`	No	Must be true: this is a sensitive, audited action. Otherwise the call is refused.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.0.0Jul 29, 2026

TDQS

A4/5.0

Behavior3/5

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

The description discloses that the action is guarded, audited, and requires confirmation, but does not detail potential side effects, error behavior, or return format beyond 'resulting value'.

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?

Two brief sentences with critical info front-loaded ('GUARDED') and no redundant text; every word adds value.

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

Completeness4/5

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

For a simple tool with 2 params and no output schema, the description covers purpose, guard, and required confirm. It lacks error or return details but is largely sufficient.

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

Parameters3/5

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

Schema coverage is 50% (code lacks description). The description adds that confirm must be true and that code is arbitrary Lua, but does not explain code syntax or limits, leaving the agent to infer from context.

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 executes arbitrary Lua code server-side and returns the result, using specific verbs and distinguishing it from sibling tools like run_console_command.

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 notes it is guarded, requires confirm, and is audited, implying sensitive use, but does not explicitly compare to alternatives or state when not to use.

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