add_review_comment · GitLab Review MCP: Risk & Policy

WHAT IT DOES

What add_review_comment does on GitLab Review MCP

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

WHY IT NEEDS A POLICY

Why add_review_comment needs a policy

This tool creates new comments on pull requests, which modifies repository state reversibly. While the action is persistent, comments can be edited or deleted, making it a Write operation rather than Destructive.

From the tool's definition Tool description states 'Add a review comment to a pull request', which creates new comment data in the repository system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_review_comment Rate-limited

add_review_comment 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_review_comment": {
      "limits": [
        {
          "counter": "add_review_comment_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 GitLab Review MCP, so you can run agents against it safely.

FAQ

Questions about add_review_comment

What does the add_review_comment tool do? +

Add a review comment to a pull request. It is categorised as a Write tool in the GitLab Review MCP 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_review_comment? +

Register the GitLab Review MCP server in PolicyLayer and add a rule for add_review_comment: 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 GitLab Review MCP. Nothing to install.

What risk level is add_review_comment? +

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

Can I rate-limit add_review_comment? +

Yes. Add a rate_limit block to the add_review_comment 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_review_comment completely? +

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

add_review_comment is provided by the GitLab Review MCP server (lininn/gitlab-review-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.