create_weld · Melo MCP: Risk & Policy

WHAT IT DOES

What create_weld does on Melo

AI agents use create_weld to create or update resources in Melo — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Melo environment.

WHY IT NEEDS A POLICY

Why create_weld needs a policy

This tool creates a new constraint object that modifies the relationship between parts in Roblox Studio. While it alters the project state, WeldConstraints are reversible (can be deleted), making it a Write operation rather than Destructive.

From the tool's definition Tool 'create_weld' creates a WeldConstraint between two parts, which is a reversible modification to the scene structure.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_weld Rate-limited

create_weld stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_weld": {
      "limits": [
        {
          "counter": "create_weld_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Melo, so you can run agents against it safely.

FAQ

Questions about create_weld

What does the create_weld tool do? +

Create a WeldConstraint between two parts. Args: - part0 (string): Path to the first part - part1 (string): Path to the second part Returns: Confirmation with weld path. It is categorised as a Write tool in the Melo MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_weld? +

Register the Melo MCP server in PolicyLayer and add a rule for create_weld: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Melo. Nothing to install.

What risk level is create_weld? +

create_weld is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_weld? +

Yes. Add a rate_limit block to the create_weld rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block create_weld completely? +

Set action: deny in the PolicyLayer policy for create_weld. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides create_weld? +

create_weld is provided by the Melo MCP server (yannyhl/linkedsword-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.