AI agents call show-table to retrieve information from Supabase MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays existing table data without side effects. While it may expose sensitive database contents depending on access controls and data sensitivity, the tool itself performs a read-only operation. The severity is low because the action is non-destructive and reversible; impact depends on what data exists in the table and who has access, but the tool's core function is query/retrieval only.
From the tool's definition Tool name 'show-table' and description 'Display data from a specific table' indicate data retrieval with no modification or deletion.
Documented attack patterns abuse exactly the kind of access show-table gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Supabase MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for show-table:
{
"version": "1",
"default": "deny",
"tools": {
"show-table": {}
}
}show-table is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Display data from a specific table. It is categorised as a Read tool in the Supabase MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Supabase MCP Server MCP server in PolicyLayer and add a rule for show-table: 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 Supabase MCP Server. Nothing to install.
show-table is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the show-table 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.
Set action: deny in the PolicyLayer policy for show-table. 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.
show-table is provided by the Supabase MCP Server MCP server (mcp-use/supabase-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Supabase MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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3 Supabase MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.