merge_zones · Elastic Brain ZH MCP: Risk & Policy

WHAT IT DOES

What merge_zones does on Elastic Brain ZH

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

WHY IT NEEDS A POLICY

Why merge_zones needs a policy

The merge_zones tool performs a reversible modification operation on memory zones (data structures in the Elasticsearch system). While merging could theoretically result in data loss if conflicts are resolved by overwriting one zone's data, the presence of 'conflict resolution options' suggests the operation is controlled and reversible—zones could be restored or the merge undone.

From the tool's definition Tool name: 'merge_zones' with description stating it 'Merge multiple zones with conflict resolution options.' This operation modifies the state of multiple zones by combining them, which constitutes creating or modifying data in a reversible manner.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

merge_zones Rate-limited

merge_zones 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_zones": {
      "limits": [
        {
          "counter": "merge_zones_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 Elastic Brain ZH, so you can run agents against it safely.

FAQ

Questions about merge_zones

What does the merge_zones tool do? +

Merge multiple zones with conflict resolution options. It is categorised as a Write tool in the Elastic Brain ZH 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_zones? +

Register the Elastic Brain ZH MCP server in PolicyLayer and add a rule for merge_zones: 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 Elastic Brain ZH. Nothing to install.

What risk level is merge_zones? +

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

Can I rate-limit merge_zones? +

Yes. Add a rate_limit block to the merge_zones 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_zones completely? +

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

merge_zones is provided by the Elastic Brain ZH MCP server (tocharianou/elastic-brain-zh). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.