open_nodes

ServerKnowledgeGraph MCP Server
CategoryRead

WHAT IT DOES

What open_nodes does on KnowledgeGraph MCP Server

AI agents call open_nodes to retrieve information from KnowledgeGraph MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

THE RISK

Low Risk

Why open_nodes needs a policy

This tool only retrieves and returns data about specified entities and their relationships. It has no side effects, does not modify any data, and is purely a read/query operation on the knowledge graph.

From the tool's definition RETRIEVE specific ENTITIES by exact names along with their interconnections. Returns detailed information

Documented attack patterns abuse exactly the kind of access open_nodes gives an agent:

POLICY

How to control open_nodes

PolicyLayer is an MCP gateway — it sits between your AI agents and KnowledgeGraph MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for open_nodes:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "open_nodes": {}
  }
}

open_nodes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register KnowledgeGraph MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More KnowledgeGraph MCP Server tools

Destructive delete_entities Permanently DELETE entities and all their RELATIONSHIPS. This action is irreversible and c Destructive delete_observations DELETE specific OBSERVATIONS from entities while preserving the entity, its relationships, Destructive delete_relations DELETE specific RELATIONSHIPS between entities while preserving both entities. Use for upd Write remove_tags REMOVE specific TAGS from existing entities to maintain accurate categorization. Use for s Write add_observations ADD new factual observations to existing entities. Requires exact entity names that exist Write add_tags ADD categorical TAGS to existing entities for filtering and organization. Tags are case-se Write create_entities CREATE new entities with OBSERVATIONS and optional tags. MANDATORY: If creating multiple e Write create_relations CREATE directional RELATIONSHIPS between existing entities. Both source and target entitie

All 11 KnowledgeGraph MCP Server tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about open_nodes

What does the open_nodes tool do? +

RETRIEVE specific ENTITIES by exact names along with their interconnections. Returns detailed information about the specified entities and relationships between them. Requires knowing exact entity names. It is categorised as a Read tool in the KnowledgeGraph MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on open_nodes? +

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

What risk level is open_nodes? +

open_nodes is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit open_nodes? +

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

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

open_nodes is provided by the KnowledgeGraph MCP Server MCP server (n-r-w/knowledgegraph-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every KnowledgeGraph MCP Server tool call.

Start from KnowledgeGraph MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →

Free to start. No card required.

11 KnowledgeGraph MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.