update_entities · Elastic Brain ZH MCP: Risk & Policy

WHAT IT DOES

What update_entities does on Elastic Brain ZH

AI agents use update_entities 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 update_entities needs a policy

The tool modifies entities in an Elasticsearch-based knowledge graph, which is a write operation that changes stored data. Updates are reversible (can be undone with subsequent updates or rollbacks), distinguishing this from the Destructive category. The confidence is high because 'update' is an unambiguous indicator of write-class operations.

From the tool's definition The tool is named 'update_entities' and described as 'Update entities in knowledge graph (memory)'. The verb 'update' indicates modification of existing data in a reversible manner.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_entities Rate-limited

update_entities 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": {
    "update_entities": {
      "limits": [
        {
          "counter": "update_entities_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 update_entities

What does the update_entities tool do? +

Update entities in knowledge graph (memory). 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 update_entities? +

Register the Elastic Brain ZH MCP server in PolicyLayer and add a rule for update_entities: 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 update_entities? +

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

Can I rate-limit update_entities? +

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

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

update_entities 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.