add_group_member · Mcp Gitlab MCP: Risk & Policy

WHAT IT DOES

What add_group_member does on Mcp Gitlab

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

WHY IT NEEDS A POLICY

Why add_group_member needs a policy

This tool creates new group memberships and modifies access control settings. While the default dry_run safety reduces immediate risk, the actual execution grants permissions that alter who can access resources. This is a Write operation (reversible change to system state) rather than Read.

From the tool's definition add_group_member adds a user to a group with a specified access level, directly modifying group membership and permissions. The description states 'dry_run=true by default', indicating this creates reversible changes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_group_member Rate-limited

add_group_member 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_group_member": {
      "limits": [
        {
          "counter": "add_group_member_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 Mcp Gitlab, so you can run agents against it safely.

FAQ

Questions about add_group_member

What does the add_group_member tool do? +

Add a user to a group with a given access level. dry_run=true by default. It is categorised as a Write tool in the Mcp Gitlab 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_group_member? +

Register the Mcp Gitlab MCP server in PolicyLayer and add a rule for add_group_member: 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 Mcp Gitlab. Nothing to install.

What risk level is add_group_member? +

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

Can I rate-limit add_group_member? +

Yes. Add a rate_limit block to the add_group_member 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_group_member completely? +

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

add_group_member is provided by the Mcp Gitlab MCP server (wanadev/gitlab-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.