mcp_add_tool

Add a new MCP tool dynamically (adds to tools list and handler)

SERVERClaude C2 SOURCE0xyg3n/claude-c2

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/0xyg3n-claude-c2/mcp-add-tool.md

WHAT IT DOES

What mcp_add_tool does on Claude C2

AI agents invoke mcp_add_tool to trigger actions in Claude C2. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

RISK

Why mcp_add_tool is rated High

This tool allows dynamic addition of new MCP tools and handlers at runtime on a remote system. In the context of a server that already exposes tools like amsi_bypass, bypassuac, browser_creds, and defender_exclude, the ability to inject arbitrary new tools/handlers represents a critical code execution and privilege escalation vector. An attacker could introduce malicious tools with arbitrary capabilities.

From the tool's definition Add a new MCP tool dynamically (adds to tools list and handler)

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs mcp_add_tool safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Claude C2, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For mcp_add_tool, this is the rule to start with:

mcp_add_tool Rate-limited

mcp_add_tool stays usable, but rate-capped: a runaway agent can't fire it dozens of times 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_add_tool": {
      "limits": [
        {
          "counter": "mcp_add_tool_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Claude C2, apply this rule, and every mcp_add_tool call is checked against it from then on.

FAQ

Questions about mcp_add_tool

What does the mcp_add_tool tool do? +

Add a new MCP tool dynamically (adds to tools list and handler). It is categorised as a Execute tool in the Claude C2 MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on mcp_add_tool? +

Register the Claude C2 MCP server in PolicyLayer and add a rule for mcp_add_tool: 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 Claude C2. Nothing to install.

What risk level is mcp_add_tool? +

mcp_add_tool is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit mcp_add_tool? +

Yes. Add a rate_limit block to the mcp_add_tool 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_add_tool completely? +

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

mcp_add_tool is provided by the Claude C2 MCP server (0xyg3n/claude-c2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Claude C2, and thousands of servers like it.

This server

All 94 Claude C2 tools → High-risk tools on this server →

Across the catalogue

All high-risk MCP tools → The MCP Attack Database →

Guides

Govern code and CI agents →Agent sandbox →Least privilege for MCP →