merge_units · Mealie MCP Server MCP: Risk & Policy

WHAT IT DOES

What merge_units does on Mealie MCP Server

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

WHY IT NEEDS A POLICY

Why merge_units needs a policy

Merging units modifies the data structure by combining units but remains reversible through subsequent operations. This is a write operation that alters configuration data (units), but the blast radius is limited to the recipe system's unit taxonomy and does not cause financial harm, irreversible deletion, or code execution.

From the tool's definition Tool description states 'Merge one unit into another (consolidate duplicates)' which modifies existing unit data by consolidating them into a single unit.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

merge_units Rate-limited

merge_units 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": {
    "merge_units": {
      "limits": [
        {
          "counter": "merge_units_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 Mealie MCP Server, so you can run agents against it safely.

FAQ

Questions about merge_units

What does the merge_units tool do? +

Merge one unit into another (consolidate duplicates). It is categorised as a Write tool in the Mealie 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 merge_units? +

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

What risk level is merge_units? +

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

Can I rate-limit merge_units? +

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

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

merge_units is provided by the Mealie MCP Server MCP server (nikopol666/mealie-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.