supabase_query · VibeServe MCP: Risk & Policy

WHAT IT DOES

What supabase_query does on VibeServe

AI agents invoke supabase_query to trigger actions in VibeServe. 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_query needs a policy

The description is minimal and uninformative about whether this is read-only or allows arbitrary SQL. 'Query' in the context of a database can include DML/DDL operations (INSERT, UPDATE, DELETE, DROP).

From the tool's definition 'Query a Supabase table' — the tool name includes 'query' which could range from read-only SELECT to arbitrary SQL execution including destructive statements

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

supabase_query Rate-limited

supabase_query 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_query": {
      "limits": [
        {
          "counter": "supabase_query_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 VibeServe, so you can run agents against it safely.

FAQ

Questions about supabase_query

What does the supabase_query tool do? +

Query a Supabase table. It is categorised as a Execute tool in the VibeServe 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_query? +

Register the VibeServe MCP server in PolicyLayer and add a rule for supabase_query: 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 VibeServe. Nothing to install.

What risk level is supabase_query? +

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

Can I rate-limit supabase_query? +

Yes. Add a rate_limit block to the supabase_query 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_query completely? +

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

supabase_query is provided by the VibeServe MCP server (ncsound919/vibeserve). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.