mcp_tool_add · SIN-Code MCP Server Builder Skill MCP

WHAT IT DOES

What mcp_tool_add does on SIN-Code MCP Server Builder Skill

AI agents use mcp_tool_add to create or update resources in SIN-Code MCP Server Builder Skill — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your SIN-Code MCP Server Builder Skill environment.

WHY IT NEEDS A POLICY

Why mcp_tool_add needs a policy

This tool creates or modifies MCP server definitions by adding new tool entries. While reversible (can be undone by removal or editing), it modifies server code/configuration that affects what capabilities are exposed. Severity is high because a compromised AI agent could add malicious tools to an MCP server, expanding its attack surface or enabling privilege escalation within the ecosystem.

From the tool's definition Tool name 'mcp_tool_add' combined with server purpose of scaffolding MCP servers and context of sibling tools (mcp_scaffold, mcp_validate, mcp_publish) indicates this adds tool definitions to MCP server code.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mcp_tool_add Rate-limited

mcp_tool_add 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": {
    "mcp_tool_add": {
      "limits": [
        {
          "counter": "mcp_tool_add_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 SIN-Code MCP Server Builder Skill, so you can run agents against it safely.

FAQ

Questions about mcp_tool_add

What does the mcp_tool_add tool do? +

mcp_tool_add. It is categorised as a Write tool in the SIN-Code MCP Server Builder Skill MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mcp_tool_add? +

Register the SIN-Code MCP Server Builder Skill MCP server in PolicyLayer and add a rule for mcp_tool_add: 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 SIN-Code MCP Server Builder Skill. Nothing to install.

What risk level is mcp_tool_add? +

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

Can I rate-limit mcp_tool_add? +

Yes. Add a rate_limit block to the mcp_tool_add 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 mcp_tool_add completely? +

Set action: deny in the PolicyLayer policy for mcp_tool_add. 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 mcp_tool_add? +

mcp_tool_add is provided by the SIN-Code MCP Server Builder Skill MCP server (opensin-code/sin-code-mcp-server-builder-skill). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.