get_knowledge_graph

THE RISK

Low Risk

Why get_knowledge_graph needs a policy

The tool performs a data retrieval operation on the Obsidian vault's knowledge graph structure. No side effects, no creation or modification of notes, no deletion, and no external execution. This is a straightforward read operation with minimal security risk even if called repeatedly or with unusual arguments.

From the tool's definition Tool name is 'get_knowledge_graph' and description states 'Get the complete knowledge graph for a vault' — this retrieves and queries data without modifying, deleting, or executing operations.

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

POLICY

How to control get_knowledge_graph

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

policy.json

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

get_knowledge_graph 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 Obsidian 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

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All 29 Obsidian 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 get_knowledge_graph

What does the get_knowledge_graph tool do? +

Get the complete knowledge graph for a vault. It is categorised as a Read tool in the Obsidian MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on get_knowledge_graph? +

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

What risk level is get_knowledge_graph? +

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

Can I rate-limit get_knowledge_graph? +

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

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

get_knowledge_graph is provided by the Obsidian MCP Server MCP server (bazylhorsey/obsidian-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Obsidian MCP Server tool call.

Start from Obsidian 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 →