update_model

THE RISK

Medium Risk

Why update_model needs a policy

This tool modifies existing model configurations (name, system prompt, parameters) rather than reading, executing arbitrary operations, destructively deleting, or handling financial transactions.

From the tool's definition Tool description states it 'Update[s] a model's name, system prompt, or parameters' — a modification operation that creates or changes data reversibly. The tool does not delete or destroy data, nor does it execute arbitrary code or move financial resources.

Documented attack patterns abuse exactly the kind of access update_model gives an agent:

POLICY

How to control update_model

PolicyLayer is an MCP gateway — it sits between your AI agents and Open WebUI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_model:

policy.json

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

update_model 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.

Create a free account and register Open WebUI MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Open WebUI MCP Server tools

Destructive delete_all_chats Delete all your chats. WARNING: Cannot be undone! Destructive delete_all_files Delete all files. ADMIN ONLY. WARNING: Cannot be undone! Destructive delete_all_memories Delete all your memories. WARNING: Cannot be undone! Destructive delete_channel Delete a channel and all its messages. Destructive delete_channel_message Delete a message from a channel. Destructive delete_chat Delete a chat. Destructive delete_file Delete a file. Destructive delete_folder Delete a folder.

All 82 Open WebUI MCP Server tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about update_model

What does the update_model tool do? +

Update a model's name, system prompt, or parameters. It is categorised as a Write tool in the Open WebUI 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_model? +

Register the Open WebUI MCP Server MCP server in PolicyLayer and add a rule for update_model: 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 Open WebUI MCP Server. Nothing to install.

What risk level is update_model? +

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

Can I rate-limit update_model? +

Yes. Add a rate_limit block to the update_model 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_model completely? +

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

update_model is provided by the Open WebUI MCP Server MCP server (troylar/open-webui-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Open WebUI MCP Server tool call.

Start from Open WebUI MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →