insert_row · Postgres MCP: Risk & Policy

WHAT IT DOES

What insert_row does on Postgres

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

WHY IT NEEDS A POLICY

Why insert_row needs a policy

INSERT is a write operation that creates new data in the database. While reversible (via DELETE), it modifies the database state and could corrupt data integrity if misused by an agent (e.g., inserting duplicate records, incorrect financial entries, or sensitive data).

From the tool's definition Tool performs INSERT operation, creating new database records. Description explicitly states 'INSERT a single row into a table and return the inserted record', confirming data modification without deletion or reversal constraints.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

insert_row Rate-limited

insert_row 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_row": {
      "limits": [
        {
          "counter": "insert_row_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 Postgres, so you can run agents against it safely.

FAQ

Questions about insert_row

What does the insert_row tool do? +

INSERT a single row into a table and return the inserted record. It is categorised as a Write tool in the Postgres 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_row? +

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

What risk level is insert_row? +

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

Can I rate-limit insert_row? +

Yes. Add a rate_limit block to the insert_row 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_row completely? +

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

insert_row is provided by the Postgres MCP server (santisanti13/postgres-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.