query_subgraph · Predictfun MCP: Risk & Policy

WHAT IT DOES

What query_subgraph does on Predictfun

AI agents invoke query_subgraph to trigger actions in Predictfun. 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 query_subgraph needs a policy

This tool executes arbitrary GraphQL queries against the subgraphs. While GraphQL is typically read-only, 'custom' and 'any subgraph' queries introduce uncertainty about scope. The tool's primary risk is that it allows arbitrary query construction which could be used to extract sensitive data or, if mutations are supported, modify state.

From the tool's definition "Run a custom GraphQL query against any Predict.fun subgraph" — executes arbitrary user-supplied GraphQL queries

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

query_subgraph Rate-limited

query_subgraph 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": {
    "query_subgraph": {
      "limits": [
        {
          "counter": "query_subgraph_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 Predictfun, so you can run agents against it safely.

FAQ

Questions about query_subgraph

What does the query_subgraph tool do? +

Run a custom GraphQL query against any Predict.fun subgraph. Use this for advanced queries not covered by other tools. It is categorised as a Execute tool in the Predictfun MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on query_subgraph? +

Register the Predictfun MCP server in PolicyLayer and add a rule for query_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 Predictfun. Nothing to install.

What risk level is query_subgraph? +

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

Can I rate-limit query_subgraph? +

Yes. Add a rate_limit block to the query_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 query_subgraph completely? +

Set action: deny in the PolicyLayer policy for query_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 query_subgraph? +

query_subgraph is provided by the Predictfun MCP server (paulieb14/predictfun-subgraphs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.