gqlfed_add_subgraph

Add federated subgraph

SERVERPlugin Hub SOURCE@barnburner121/plugin-hub-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/barnburner121-plugin-hub-mcp/gqlfed-add-subgraph.md

WHAT IT DOES

What gqlfed_add_subgraph does on Plugin Hub

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

RISK

Why gqlfed_add_subgraph is rated Medium

An AI agent can call gqlfed_add_subgraph faster than any human can review: one bad instruction and it creates or modifies resources in Plugin Hub by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs gqlfed_add_subgraph safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Plugin Hub, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For gqlfed_add_subgraph, this is the rule to start with:

gqlfed_add_subgraph Rate-limited

gqlfed_add_subgraph 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": {
    "gqlfed_add_subgraph": {
      "limits": [
        {
          "counter": "gqlfed_add_subgraph_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Plugin Hub, apply this rule, and every gqlfed_add_subgraph call is checked against it from then on.

FAQ

Questions about gqlfed_add_subgraph

What does the gqlfed_add_subgraph tool do? +

Add federated subgraph. It is categorised as a Write tool in the Plugin Hub MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on gqlfed_add_subgraph? +

Register the Plugin Hub MCP server in PolicyLayer and add a rule for gqlfed_add_subgraph: 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 Plugin Hub. Nothing to install.

What risk level is gqlfed_add_subgraph? +

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

Can I rate-limit gqlfed_add_subgraph? +

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

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

gqlfed_add_subgraph is provided by the Plugin Hub MCP server (@barnburner121/plugin-hub-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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