update_rule · Requestly MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_rule does on Requestly MCP Server

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

WHY IT NEEDS A POLICY

Why update_rule needs a policy

This tool modifies existing data reversibly. While Requestly rules can affect request/response handling (potentially impacting application behavior), the update_rule operation itself is reversible—changes can be undone by updating again or reverting to previous values. This makes it Write rather than Execute or Destructive.

From the tool's definition Tool description states 'Update an existing rule in Requestly. Requires ruleId and the updated rule payload.' The word 'Update' combined with 'updated rule payload' indicates modification of existing data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_rule Rate-limited

update_rule 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": {
    "update_rule": {
      "limits": [
        {
          "counter": "update_rule_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 Requestly MCP Server, so you can run agents against it safely.

FAQ

Questions about update_rule

What does the update_rule tool do? +

Update an existing rule in Requestly. Requires ruleId and the updated rule payload. It is categorised as a Write tool in the Requestly 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_rule? +

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

What risk level is update_rule? +

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

Can I rate-limit update_rule? +

Yes. Add a rate_limit block to the update_rule 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_rule completely? +

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

update_rule is provided by the Requestly MCP Server MCP server (requestly/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.