call_dynamic_tool · Ultimate-MCP-Server MCP: Risk & Policy

WHAT IT DOES

What call_dynamic_tool does on Ultimate-MCP-Server

AI agents invoke call_dynamic_tool to trigger actions in Ultimate-MCP-Server. 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.

WHY IT NEEDS A POLICY

Why call_dynamic_tool needs a policy

The name strongly implies executing tools dynamically at runtime, which is characteristic of an Execute-class tool. In the context of an agent orchestration server, a 'dynamic tool caller' could invoke any available tool, including destructive or financial ones, making it high blast radius. Empty description lowers confidence but the name pattern and server context (agent orchestration) push severity to critical.

From the tool's definition Tool name 'call_dynamic_tool' — 'dynamic' implies runtime execution of arbitrary or parameterized operations; no description provided to constrain scope.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

call_dynamic_tool Rate-limited

call_dynamic_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": {
    "call_dynamic_tool": {
      "limits": [
        {
          "counter": "call_dynamic_tool_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about call_dynamic_tool

What does the call_dynamic_tool tool do? +

call_dynamic_tool. It is categorised as a Execute tool in the Ultimate-MCP-Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on call_dynamic_tool? +

Register the Ultimate-MCP-Server MCP server in PolicyLayer and add a rule for call_dynamic_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 Ultimate-MCP-Server. Nothing to install.

What risk level is call_dynamic_tool? +

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

Can I rate-limit call_dynamic_tool? +

Yes. Add a rate_limit block to the call_dynamic_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 call_dynamic_tool completely? +

Set action: deny in the PolicyLayer policy for call_dynamic_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 call_dynamic_tool? +

call_dynamic_tool is provided by the Ultimate-MCP-Server MCP server (logos-parthenos-ai/ultimate_mcp_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.