supabase.rpc · MCP Fullstack MCP: Risk & Policy

WHAT IT DOES

What supabase.rpc does on MCP Fullstack

AI agents invoke supabase.rpc to trigger actions in MCP Fullstack. 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 supabase.rpc needs a policy

Calling an RPC function means executing arbitrary server-side code/procedures in Supabase. The effects depend entirely on which function is called and its arguments - it could read, write, delete data, or trigger external operations.

From the tool's definition 'Call Supabase RPC function' - RPC (Remote Procedure Call) executes arbitrary server-side functions

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

supabase.rpc Rate-limited

supabase.rpc 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": {
    "supabase.rpc": {
      "limits": [
        {
          "counter": "supabase.rpc_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 MCP Fullstack, so you can run agents against it safely.

FAQ

Questions about supabase.rpc

What does the supabase.rpc tool do? +

Call Supabase RPC function. It is categorised as a Execute tool in the MCP Fullstack MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on supabase.rpc? +

Register the MCP Fullstack MCP server in PolicyLayer and add a rule for supabase.rpc: 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 MCP Fullstack. Nothing to install.

What risk level is supabase.rpc? +

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

Can I rate-limit supabase.rpc? +

Yes. Add a rate_limit block to the supabase.rpc 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 supabase.rpc completely? +

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

supabase.rpc is provided by the MCP Fullstack MCP server (jacobfv/mcp-fullstack). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.