set_x_group · OpenAPI REST MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_x_group does on OpenAPI REST MCP Server

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

WHY IT NEEDS A POLICY

Why set_x_group needs a policy

This tool modifies request headers used for authentication or authorization context (x-group typically denotes group/role membership). While it doesn't directly modify application data, it alters the security context for all downstream API calls, potentially allowing an AI agent to escalate privileges, change access scope, or impersonate different groups.

From the tool's definition Tool name 'set_x_group' and description 'Set the x-group header value' indicates modification of request headers that affect downstream API behavior. This is a write operation that changes state (header configuration) for subsequent requests.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_x_group Rate-limited

set_x_group 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": {
    "set_x_group": {
      "limits": [
        {
          "counter": "set_x_group_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 OpenAPI REST MCP Server, so you can run agents against it safely.

FAQ

Questions about set_x_group

What does the set_x_group tool do? +

Set the x-group header value to use for downstream API requests (overrides environment default). It is categorised as a Write tool in the OpenAPI REST 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 set_x_group? +

Register the OpenAPI REST MCP Server MCP server in PolicyLayer and add a rule for set_x_group: 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 OpenAPI REST MCP Server. Nothing to install.

What risk level is set_x_group? +

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

Can I rate-limit set_x_group? +

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

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

set_x_group is provided by the OpenAPI REST MCP Server MCP server (saranazeer27/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.