scan_folder · Syncthing MCP Server MCP: Risk & Policy

WHAT IT DOES

What scan_folder does on Syncthing MCP Server

AI agents invoke scan_folder to trigger actions in Syncthing MCP Server. 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 scan_folder needs a policy

This tool actively triggers an operation (rescan) on the Syncthing instance rather than simply reading data. It causes Syncthing to scan the filesystem and detect changes, which is an external operation with side effects (could trigger sync operations, update indices, and propagate changes to connected devices).

From the tool's definition Trigger a rescan of a folder to detect local changes

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

scan_folder Rate-limited

scan_folder 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": {
    "scan_folder": {
      "limits": [
        {
          "counter": "scan_folder_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 Syncthing MCP Server, so you can run agents against it safely.

FAQ

Questions about scan_folder

What does the scan_folder tool do? +

Trigger a rescan of a folder to detect local changes. It is categorised as a Execute tool in the Syncthing MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on scan_folder? +

Register the Syncthing MCP Server MCP server in PolicyLayer and add a rule for scan_folder: 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 Syncthing MCP Server. Nothing to install.

What risk level is scan_folder? +

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

Can I rate-limit scan_folder? +

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

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

scan_folder is provided by the Syncthing MCP Server MCP server (zaphodsdad/syncthing-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.