stepi · Rr MCP: Risk & Policy

WHAT IT DOES

What stepi does on Rr

AI agents invoke stepi 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 stepi needs a policy

stepi advances the program counter by one machine instruction in a live rr debugging session. This is an execution-control action that changes the runtime state of the debugged process. It has no direct data destruction or financial impact, but misuse could advance execution past critical checkpoints or alter program state in ways that are difficult to undo, making it Execute with medium severity.

From the tool's definition 'Step forward one machine instruction' — advances execution state in a live debugging session

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stepi Rate-limited

stepi 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": {
    "stepi": {
      "limits": [
        {
          "counter": "stepi_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 stepi

What does the stepi tool do? +

Step forward one machine instruction. Use for. 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 stepi? +

Register the Rr MCP server in PolicyLayer and add a rule for stepi: 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 stepi? +

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

Can I rate-limit stepi? +

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

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

stepi 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.