merge_entities · LightRAG MCP Server MCP: Risk & Policy

WHAT IT DOES

What merge_entities does on LightRAG MCP Server

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

WHY IT NEEDS A POLICY

Why merge_entities needs a policy

The tool modifies data (merges entities) but is classified as Write rather than Destructive because the underlying data is not deleted—entities are consolidated into a unified representation. However, the high severity reflects that merging entities in a knowledge graph can have significant downstream effects on query results, entity relationships, and retrieval-augmented generation outcomes.

From the tool's definition merge_entities performs an irreversible modification of the knowledge graph by combining multiple entities into a single entity. This operation modifies the graph structure and entity definitions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

merge_entities Rate-limited

merge_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": {
    "merge_entities": {
      "limits": [
        {
          "counter": "merge_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 LightRAG MCP Server, so you can run agents against it safely.

FAQ

Questions about merge_entities

What does the merge_entities tool do? +

Merge multiple entities into a single entity. It is categorised as a Write tool in the LightRAG 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_entities? +

Register the LightRAG MCP Server MCP server in PolicyLayer and add a rule for merge_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 LightRAG MCP Server. Nothing to install.

What risk level is merge_entities? +

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

Can I rate-limit merge_entities? +

Yes. Add a rate_limit block to the merge_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 merge_entities completely? +

Set action: deny in the PolicyLayer policy for merge_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 merge_entities? +

merge_entities is provided by the LightRAG MCP Server MCP server (lalitsuryan/lightragmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.