add_device · Syncthing MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_device does on Syncthing MCP Server

AI agents use add_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 add_device needs a policy

Adding a device to Syncthing creates a new connection/pairing relationship and modifies the instance configuration. This is reversible (devices can be removed), so it falls under Write rather than Destructive or Execute. The empty description limits confidence, but the naming pattern and server context (managing Syncthing instances) strongly suggest configuration modification.

From the tool's definition Tool name is 'add_device' with empty description. The name indicates creation/addition of a device to a Syncthing instance.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_device Rate-limited

add_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": {
    "add_device": {
      "limits": [
        {
          "counter": "add_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 add_device

What does the add_device tool do? +

add_device. 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 add_device? +

Register the Syncthing MCP Server MCP server in PolicyLayer and add a rule for add_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 add_device? +

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

Can I rate-limit add_device? +

Yes. Add a rate_limit block to the add_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 add_device completely? +

Set action: deny in the PolicyLayer policy for add_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 add_device? +

add_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.