reverse_step · Rr MCP: Risk & Policy

WHAT IT DOES

What reverse_step does on Rr

AI agents invoke reverse_step to trigger actions in Rr. 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 reverse_step needs a policy

This tool triggers a reverse execution operation within an rr debugging session. It actively controls program execution flow (in reverse), which constitutes an Execute-class action. It does not merely read state but drives the debugger to step backward through execution, potentially changing the session state and register/memory view.

From the tool's definition Step backward one source line, entering into function calls in reverse

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

reverse_step Rate-limited

reverse_step 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": {
    "reverse_step": {
      "limits": [
        {
          "counter": "reverse_step_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 Rr, so you can run agents against it safely.

FAQ

Questions about reverse_step

What does the reverse_step tool do? +

Step backward one source line, entering into function calls in reverse. It is categorised as a Execute tool in the Rr MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on reverse_step? +

Register the Rr MCP server in PolicyLayer and add a rule for reverse_step: 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 Rr. Nothing to install.

What risk level is reverse_step? +

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

Can I rate-limit reverse_step? +

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

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

reverse_step is provided by the Rr MCP server (jnjaeschke/rr-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

reverse_step is one line of Rr's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →