update_rules

THE RISK

Medium Risk

Why update_rules needs a policy

The tool modifies local state by installing new rule versions, making it a Write operation rather than Read-only. While it's reversible (can be downgraded or rolled back), it changes system configuration.

From the tool's definition Tool description states 'Download and install the latest version of critical rules from GitHub' — this performs an update/installation operation that modifies the system's rule set.

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

POLICY

How to control update_rules

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

policy.json

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

update_rules 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 Claude Critical Rules 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 Claude Critical Rules MCP Server tools

Read check_for_updates Check if a new version of the critical rules is available on GitHub Read get_rules_summary Get a concise summary of the critical rules categories and main requirements Read get_version_info Get current version information and check if updates are available Read verify_compliance Verify if all mandatory checks from the critical rules have been completed before starting

All 5 Claude Critical Rules 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_rules

What does the update_rules tool do? +

Download and install the latest version of critical rules from GitHub. It is categorised as a Write tool in the Claude Critical Rules 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_rules? +

Register the Claude Critical Rules MCP Server MCP server in PolicyLayer and add a rule for update_rules: 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 Claude Critical Rules MCP Server. Nothing to install.

What risk level is update_rules? +

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

Can I rate-limit update_rules? +

Yes. Add a rate_limit block to the update_rules 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_rules completely? +

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

update_rules is provided by the Claude Critical Rules MCP Server MCP server (optimaquantum/claude-critical-rules-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Claude Critical Rules MCP Server tool call.

Start from Claude Critical Rules 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 →