graph_cypher · Graph-Memory MCP: Risk & Policy

WHAT IT DOES

What graph_cypher does on Graph-Memory

AI agents invoke graph_cypher to trigger actions in Graph-Memory. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why graph_cypher needs a policy

Although the tool enforces read-only constraints via Neo4j executeRead(), it allows the AI to generate and execute arbitrary Cypher queries against a personal knowledge graph.

From the tool's definition Tool description states 'Execute a read-only Cypher query' and 'You generate the Cypher — this tool just runs it.' Despite read-only enforcement, the tool permits arbitrary query generation and execution against the knowledge graph.

Risk signalsAdmin/system-level operation

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

graph_cypher Rate-limited

graph_cypher stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "graph_cypher": {
      "limits": [
        {
          "counter": "graph_cypher_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Graph-Memory, so you can run agents against it safely.

FAQ

Questions about graph_cypher

What does the graph_cypher tool do? +

Execute a read-only Cypher query against the memory graph. You generate the Cypher — this tool just runs it. Enforced read-only via Neo4j executeRead(). Use for custom queries not covered by other tools. Admin-only (must be the bootstrap tenant) — non-admin tenants would otherwise be able to bypass tenant filtering by writing raw Cypher. It is categorised as a Execute tool in the Graph-Memory MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on graph_cypher? +

Register the Graph-Memory MCP server in PolicyLayer and add a rule for graph_cypher: 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 Graph-Memory. Nothing to install.

What risk level is graph_cypher? +

graph_cypher is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit graph_cypher? +

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

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

graph_cypher is provided by the Graph-Memory MCP server (stevepridemore/graph-memory). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.