add_fact · Pyke MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_fact does on Pyke MCP Server

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

WHY IT NEEDS A POLICY

Why add_fact needs a policy

This tool adds facts to a logic programming knowledge base, which is a Create operation—modifying state reversibly. It does not execute arbitrary code, delete data irreversibly, move money, or have financial impact. The empty description lowers confidence slightly, but the name and context of sibling tools clearly indicate a Write operation.

From the tool's definition Tool name is 'add_fact' which indicates creating/adding data to a knowledge base. Sibling tools include 'add_rule', 'add_facts_and_rules', and 'clear_program', confirming this server manages mutable logical program state.

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 Pyke MCP Server, so you can run agents against it safely.

FAQ

Questions about add_fact

What does the add_fact tool do? +

add_fact. It is categorised as a Write tool in the Pyke 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 Pyke 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 Pyke 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 Pyke MCP Server MCP server (newjerseystyle/pyke-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.