checkpoint_create · Rr MCP: Risk & Policy

WHAT IT DOES

What checkpoint_create does on Rr

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

WHY IT NEEDS A POLICY

Why checkpoint_create needs a policy

Creating checkpoints modifies the debugging session state by adding a new persistent snapshot, which is a reversible write operation. It is not destructive (checkpoints can be deleted via checkpoint_delete), not financial, and not arbitrary code execution. While checkpoints enable debugging workflows, the act of creation itself is a write that alters session state.

From the tool's definition Tool name 'checkpoint_create' and description indicate it creates a snapshot/checkpoint at the current debugging position. This is a state-modifying operation that persists a new checkpoint in the debugger session.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

checkpoint_create Rate-limited

checkpoint_create 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": {
    "checkpoint_create": {
      "limits": [
        {
          "counter": "checkpoint_create_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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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 checkpoint_create

What does the checkpoint_create tool do? +

Create a checkpoint (snapshot) at the current position. Checkpoints let you. It is categorised as a Write tool in the Rr MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on checkpoint_create? +

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

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

Can I rate-limit checkpoint_create? +

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

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

checkpoint_create 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.