upsert_vertex · TG_ MCP: Risk & Policy

WHAT IT DOES

What upsert_vertex does on TG_MCP

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

WHY IT NEEDS A POLICY

Why upsert_vertex needs a policy

The tool creates or modifies vertex data in the TigerGraph database. This is a Write operation because it performs insertion or update (reversible changes), not deletion. Severity is medium because unauthorized vertex modifications could corrupt data integrity and affect downstream queries, but the scope is limited to single vertices rather than bulk destructive operations.

From the tool's definition Tool description states 'Insert or update a vertex' — explicit write operations on database entities. TigerGraph vertices are core data structures; modification affects stored state reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upsert_vertex Rate-limited

upsert_vertex 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": {
    "upsert_vertex": {
      "limits": [
        {
          "counter": "upsert_vertex_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 TG_MCP, so you can run agents against it safely.

FAQ

Questions about upsert_vertex

What does the upsert_vertex tool do? +

MCP tool: Insert or update a vertex. It is categorised as a Write tool in the TG_MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on upsert_vertex? +

Register the TG_ MCP server in PolicyLayer and add a rule for upsert_vertex: 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 TG_MCP. Nothing to install.

What risk level is upsert_vertex? +

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

Can I rate-limit upsert_vertex? +

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

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

upsert_vertex is provided by the TG_ MCP server (muzain187/tg_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.