migrate_pg · Mementos MCP: Risk & Policy

WHAT IT DOES

What migrate_pg does on Mementos

AI agents invoke migrate_pg to trigger actions in Mementos. 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 migrate_pg needs a policy

Applying schema migrations executes DDL statements against a live database (CREATE TABLE, ALTER TABLE, DROP TABLE, etc.), which can have irreversible side effects like dropping columns or tables. While it could be considered Destructive depending on the migration content, the primary action is executing database operations whose effects depend on the migration scripts.

From the tool's definition Apply PostgreSQL schema migrations to the configured RDS instance

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

migrate_pg Rate-limited

migrate_pg 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": {
    "migrate_pg": {
      "limits": [
        {
          "counter": "migrate_pg_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 Mementos, so you can run agents against it safely.

FAQ

Questions about migrate_pg

What does the migrate_pg tool do? +

Apply PostgreSQL schema migrations to the configured RDS instance. It is categorised as a Execute tool in the Mementos MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on migrate_pg? +

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

What risk level is migrate_pg? +

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

Can I rate-limit migrate_pg? +

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

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

migrate_pg is provided by the Mementos MCP server (@hasna/mementos). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.