faber_rollback · Faber MCP Server MCP: Risk & Policy

WHAT IT DOES

What faber_rollback does on Faber MCP Server

AI agents invoke faber_rollback to trigger actions in Faber MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why faber_rollback needs a policy

A rollback triggers an external deployment operation that switches the running application to a previous release. While it restores a prior state (making it partially reversible), it actively executes a deployment pipeline operation with significant blast radius — it changes the live production environment and could disrupt running services, active users, or ongoing transactions.

From the tool's definition Roll back an app to a previous release

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

faber_rollback Rate-limited

faber_rollback stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "faber_rollback": {
      "limits": [
        {
          "counter": "faber_rollback_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Faber MCP Server, so you can run agents against it safely.

FAQ

Questions about faber_rollback

What does the faber_rollback tool do? +

Roll back an app to a previous release. It is categorised as a Execute tool in the Faber MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on faber_rollback? +

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

What risk level is faber_rollback? +

faber_rollback is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit faber_rollback? +

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

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

faber_rollback is provided by the Faber MCP Server MCP server (joshtrebilco/faber-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.