list_tables

THE RISK

Low Risk

Why list_tables needs a policy

This tool retrieves metadata about database tables without executing queries, modifying data, or triggering side effects. It is a standard schema inspection operation that poses minimal risk if misused by an AI agent—the worst outcome is enumeration of table names.

From the tool's definition Tool name 'list_tables' and description 'Get list of database tables' indicate schema introspection with no modification or execution of queries.

Documented attack patterns abuse exactly the kind of access list_tables gives an agent:

POLICY

How to control list_tables

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP SQL Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_tables:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_tables": {}
  }
}

list_tables is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register MCP SQL Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP SQL Server tools

Destructive clear_caches Initialize cache data Execute execute_query Execute SQL queries Execute start_batch_processing Process multiple queries in batch Execute start_performance_monitoring Start performance monitoring Read describe_table Get structure of a specific table Read get_connection_pool_status Get database connection pool status Read get_query_stats Get query execution statistics Read get_schema Get database schema information

All 11 MCP SQL Server tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about list_tables

What does the list_tables tool do? +

Get list of database tables. It is categorised as a Read tool in the MCP SQL Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_tables? +

Register the MCP SQL Server MCP server in PolicyLayer and add a rule for list_tables: 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 SQL Server. Nothing to install.

What risk level is list_tables? +

list_tables is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_tables? +

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

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

list_tables is provided by the MCP SQL Server MCP server (ryudg/mcp-sql). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP SQL Server tool call.

Start from MCP SQL Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →