execute_sql · Datasette MCP: Risk & Policy

WHAT IT DOES

What execute_sql does on Datasette MCP

AI agents invoke execute_sql to trigger actions in Datasette MCP. 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 execute_sql needs a policy

execute_sql runs arbitrary SQL code against a database. Even in a read-only context, SQL execution is an Execute category action because it can trigger complex database operations, side effects, or unintended consequences (e.g., expensive queries causing denial of service, information disclosure via error messages, or exploitation of database-specific features).

From the tool's definition Tool name 'execute_sql' indicates it runs SQL queries. Despite the server description emphasizing 'read-only access,' the tool description is empty, which prevents full verification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

execute_sql Rate-limited

execute_sql 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": {
    "execute_sql": {
      "limits": [
        {
          "counter": "execute_sql_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 Datasette MCP, so you can run agents against it safely.

FAQ

Questions about execute_sql

What does the execute_sql tool do? +

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

How do I enforce a policy on execute_sql? +

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

What risk level is execute_sql? +

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

Can I rate-limit execute_sql? +

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

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

execute_sql is provided by the Datasette MCP server (mhalle/datasette-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.