virt_get_schemas

THE RISK

Low Risk

Why virt_get_schemas needs a policy

This tool retrieves metadata (schema names) from a Virtuoso database without side effects. It is purely informational and does not create, modify, delete, or execute operations. The blast radius of misuse is minimal — an attacker gains only schema enumeration capability, which is typically low-risk reconnaissance information.

From the tool's definition Tool description states it 'Retrieve and return a list of all schema names' — a read-only query operation with no data modification, deletion, or execution of arbitrary code.

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

POLICY

How to control virt_get_schemas

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

policy.json

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

virt_get_schemas 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 Odbc — 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 Odbc tools

Execute query_database Execute a SQL query and return results in JSON, JSONL or MD format. Execute query_database_jsonl Execute a SQL query and return results in JSONL format. Execute query_database_md Execute a SQL query and return results in MD format. Execute spasql_query Execute a SPASQL query and return results. Execute virtuoso_support_ai Tool to use the Virtuoso AI support function Execute chat_prompt_complete Tool to use the OPAL backend to complete chat prompt Read describe_table Retrieve and return a dictionary containing the definition of a table, including column na Read filter_table_names Retrieve and return a list containing information about tables whose names contain the sub

All 15 Mcp Odbc 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 virt_get_schemas

What does the virt_get_schemas tool do? +

Retrieve and return a list of all schema names from the connected Virtuoso database. It is categorised as a Read tool in the Mcp Odbc MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on virt_get_schemas? +

Register the Mcp Odbc MCP server in PolicyLayer and add a rule for virt_get_schemas: 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 Odbc. Nothing to install.

What risk level is virt_get_schemas? +

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

Can I rate-limit virt_get_schemas? +

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

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

virt_get_schemas is provided by the Mcp Odbc MCP server (openlinksoftware/mcp-odbc-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Mcp Odbc tool call.

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

CHECK YOUR STACK →