index_url · Knowledge MCP: Risk & Policy

WHAT IT DOES

What index_url does on Knowledge

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

WHY IT NEEDS A POLICY

Why index_url needs a policy

This tool retrieves content from a URL and writes it into the knowledge base (indexing). It has a side effect — modifying the knowledge base by adding indexed content — making it a Write operation. It is reversible in principle (the document could be removed), so it does not reach Destructive. Severity is medium because a malicious URL could poison the knowledge base with harmful or misleading content.

From the tool's definition Fetch and index content from a URL into the knowledge base

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

index_url Rate-limited

index_url 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": {
    "index_url": {
      "limits": [
        {
          "counter": "index_url_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 Knowledge, so you can run agents against it safely.

FAQ

Questions about index_url

What does the index_url tool do? +

Fetch and index content from a URL into the knowledge base. It is categorised as a Write tool in the Knowledge MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on index_url? +

Register the Knowledge MCP server in PolicyLayer and add a rule for index_url: 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 Knowledge. Nothing to install.

What risk level is index_url? +

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

Can I rate-limit index_url? +

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

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

index_url is provided by the Knowledge MCP server (numericalpie/knowledge-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.