reject_device · Syncthing MCP Server MCP: Risk & Policy

WHAT IT DOES

What reject_device does on Syncthing MCP Server

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

WHY IT NEEDS A POLICY

Why reject_device needs a policy

This tool modifies configuration state by rejecting a device connection, making it a Write operation rather than Read. It is reversible (unlike Destructive operations), and has medium severity because rejecting legitimate device connections could disrupt intended Syncthing synchronization topology, though the action can be undone by accepting a new connection request from that device.

From the tool's definition Tool name 'reject_device' and description 'Reject and dismiss a pending device connection request' indicate modification of device connection state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

reject_device Rate-limited

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

FAQ

Questions about reject_device

What does the reject_device tool do? +

Reject and dismiss a pending device connection request. It is categorised as a Write tool in the Syncthing MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on reject_device? +

Register the Syncthing MCP Server MCP server in PolicyLayer and add a rule for reject_device: 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 reject_device? +

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

Can I rate-limit reject_device? +

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

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

reject_device 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.