add_fact · Enhanced MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_fact does on Enhanced MCP Server

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

WHY IT NEEDS A POLICY

Why add_fact needs a policy

This tool creates new data (facts about the user) and stores it, which is a Write operation. Severity is medium because misuse could result in false or misleading information being recorded about the user, potentially affecting downstream decisions (job tracking, categorization logic), but it is reversible and does not involve financial transactions, destructive operations, or code execution.

From the tool's definition Tool name is 'add_fact' and description states 'Store a factual piece of information about the user', indicating creation/modification of user data in persistent storage.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_fact Rate-limited

add_fact 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": {
    "add_fact": {
      "limits": [
        {
          "counter": "add_fact_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 Enhanced MCP Server, so you can run agents against it safely.

FAQ

Questions about add_fact

What does the add_fact tool do? +

Store a factual piece of information about the user. It is categorised as a Write tool in the Enhanced 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 add_fact? +

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

What risk level is add_fact? +

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

Can I rate-limit add_fact? +

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

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

add_fact is provided by the Enhanced MCP Server MCP server (pbulbule13/mcpwithgoogle). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.