edit · Jj MCP: Risk & Policy

WHAT IT DOES

What edit does on Jj

AI agents invoke edit to trigger actions in Jj. 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 edit needs a policy

This tool changes the working-copy state by switching to a different revision, which is an active operation affecting the working directory. It triggers external VCS operations and modifies repository state, but is generally reversible. It fits Execute better than Write since it triggers a VCS operation rather than creating/modifying data content directly.

From the tool's definition Sets the specified revision as the working-copy revision in a Jujutsu (jj) repository

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

edit Rate-limited

edit 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": {
    "edit": {
      "limits": [
        {
          "counter": "edit_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 Jj, so you can run agents against it safely.

FAQ

Questions about edit

What does the edit tool do? +

Sets the specified revision as the working-copy revision in a Jujutsu (jj) repository. Note: it is generally recommended to instead use. It is categorised as a Execute tool in the Jj MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on edit? +

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

What risk level is edit? +

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

Can I rate-limit edit? +

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

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

edit is provided by the Jj MCP server (jj-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.