add_project_member · Mcp Gitlab MCP: Risk & Policy

WHAT IT DOES

What add_project_member does on Mcp Gitlab

AI agents use add_project_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_project_member needs a policy

This tool modifies project access control by creating a new member record, which is reversible (members can be removed). It is Write rather than Execute because it manipulates data structures (membership records) rather than triggering arbitrary operations. The severity is high because granting incorrect access levels could expose sensitive project data or enable unauthorized actions.

From the tool's definition add_project_member: 'Add a user to a project with a given access level' — this creates a new project membership binding with defined permissions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_project_member Rate-limited

add_project_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_project_member": {
      "limits": [
        {
          "counter": "add_project_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_project_member

What does the add_project_member tool do? +

Add a user to a project 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_project_member? +

Register the Mcp Gitlab MCP server in PolicyLayer and add a rule for add_project_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_project_member? +

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

Can I rate-limit add_project_member? +

Yes. Add a rate_limit block to the add_project_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_project_member completely? +

Set action: deny in the PolicyLayer policy for add_project_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_project_member? +

add_project_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.