quick_replace · MCP SmallEdit MCP: Risk & Policy

WHAT IT DOES

What quick_replace does on MCP SmallEdit

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

WHY IT NEEDS A POLICY

Why quick_replace needs a policy

This tool creates or modifies file content reversibly. While the blast radius is medium (unintended modifications could corrupt application files or data), the reversibility via backups and the lack of permanent data destruction or external effects keeps it below Execute or Destructive severity. An agent could cause harm through incorrect replacements, but this is containable via restoration.

From the tool's definition Tool performs 'find and replace' operations that 'modify' files, and the server description emphasizes 'making edits to files' and 'modifications'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

quick_replace Rate-limited

quick_replace 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": {
    "quick_replace": {
      "limits": [
        {
          "counter": "quick_replace_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about quick_replace

What does the quick_replace tool do? +

Simple find and replace across a file without regex. It is categorised as a Write tool in the MCP SmallEdit MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on quick_replace? +

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

What risk level is quick_replace? +

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

Can I rate-limit quick_replace? +

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

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

quick_replace is provided by the MCP SmallEdit MCP server (mikeybeez/mcp-smalledit). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.