create_relations · Neo4j MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_relations does on Neo4j MCP Server

AI agents use create_relations to create or update resources in Neo4j MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Neo4j MCP Server environment.

WHY IT NEEDS A POLICY

Why create_relations needs a policy

This tool creates new relations in a Neo4j knowledge graph, which is a reversible write operation. While it modifies the graph structure, relations can be deleted (as evidenced by the sibling tool 'delete_relations'), making it Write rather than Destructive.

From the tool's definition Tool name 'create_relations' and description 'Create multiple new relations between entities in the knowledge graph' explicitly indicate data creation/modification without irreversible deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_relations Rate-limited

create_relations 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": {
    "create_relations": {
      "limits": [
        {
          "counter": "create_relations_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 Neo4j MCP Server, so you can run agents against it safely.

FAQ

Questions about create_relations

What does the create_relations tool do? +

Create multiple new relations between entities in the knowledge graph. Relations should be in active voice. It is categorised as a Write tool in the Neo4j 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 create_relations? +

Register the Neo4j MCP Server MCP server in PolicyLayer and add a rule for create_relations: 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 Neo4j MCP Server. Nothing to install.

What risk level is create_relations? +

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

Can I rate-limit create_relations? +

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

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

create_relations is provided by the Neo4j MCP Server MCP server (rebots-online/mcp-neo4j). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.