insert_data · MCP PostgreSQL Server MCP: Risk & Policy

WHAT IT DOES

What insert_data does on MCP PostgreSQL Server

AI agents use insert_data to create or update resources in MCP PostgreSQL Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP PostgreSQL Server environment.

WHY IT NEEDS A POLICY

Why insert_data needs a policy

insert_data creates new database records, which is a Write operation (reversible via DELETE, unlike Destructive operations). The severity is high because inserting malicious or incorrect data into a production database could corrupt business logic, violate constraints, or cause cascading failures.

From the tool's definition Tool name 'insert_data' and description 'Insert new rows into a table' explicitly describe data creation and modification. The server claims 'read-only access' but this tool enables irreversible data insertion, contradicting that claim.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

insert_data Rate-limited

insert_data stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "insert_data": {
      "limits": [
        {
          "counter": "insert_data_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches MCP PostgreSQL Server, so you can run agents against it safely.

FAQ

Questions about insert_data

What does the insert_data tool do? +

Insert new rows into a table. It is categorised as a Write tool in the MCP PostgreSQL Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on insert_data? +

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

What risk level is insert_data? +

insert_data is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit insert_data? +

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

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

insert_data is provided by the MCP PostgreSQL Server MCP server (kristofer84/mcp-postgres). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.