update_tool_config · Vulnerable MCP Server MCP

WHAT IT DOES

What update_tool_config does on Vulnerable MCP Server

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

WHY IT NEEDS A POLICY

Why update_tool_config needs a policy

The tool modifies configuration rather than deleting it (hence Write not Destructive), and does not appear to execute code or move money. Severity is medium because configuration changes can have downstream effects on system behavior and security, but the reversible nature of updates (configs can be updated again) prevents this from being critical.

From the tool's definition Tool name is 'update_tool_config' which indicates modification of configuration data. Description is empty, limiting direct evidence, but the 'update' verb in the name clearly denotes a write operation that modifies existing state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_tool_config Rate-limited

update_tool_config 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": {
    "update_tool_config": {
      "limits": [
        {
          "counter": "update_tool_config_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 Vulnerable MCP Server, so you can run agents against it safely.

FAQ

Questions about update_tool_config

What does the update_tool_config tool do? +

update_tool_config. It is categorised as a Write tool in the Vulnerable MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_tool_config? +

Register the Vulnerable MCP Server MCP server in PolicyLayer and add a rule for update_tool_config: 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 Vulnerable MCP Server. Nothing to install.

What risk level is update_tool_config? +

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

Can I rate-limit update_tool_config? +

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

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

update_tool_config is provided by the Vulnerable MCP Server MCP server (joyghoshs/vulnerable-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.