Low Risk

list_tools

List all available tools (MCP, OpenAPI, custom).

How to control list_tools ↓

What list_tools does on Open WebUI MCP Server

AI agents call list_tools to retrieve information from Open WebUI MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

Why list_tools needs a policy

This tool performs data retrieval only—it queries and returns a list of available tools without creating, modifying, deleting, or executing any operations. It has no destructive or financial impact and poses minimal security risk if misused by an AI agent, as it only exposes metadata about available tools.

From the tool's definition Tool name 'list_tools' and description 'List all available tools' indicate a retrieval operation with no side effects. This is a query/discovery function that returns information about available tools.

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

How to control list_tools

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 list_tools:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_tools": {}
  }
}

list_tools is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

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

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Questions about list_tools

What does the list_tools tool do? +

List all available tools (MCP, OpenAPI, custom). It is categorised as a Read tool in the Open WebUI MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_tools? +

Register the Open WebUI MCP Server MCP server in PolicyLayer and add a rule for list_tools: 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 list_tools? +

list_tools is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_tools? +

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

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

list_tools 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.

Free to start. No card required.

82 Open WebUI MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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