init_schema · Pg Mnemosyne MCP: Risk & Policy

WHAT IT DOES

What init_schema does on Pg Mnemosyne

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

WHY IT NEEDS A POLICY

Why init_schema needs a policy

This tool creates a database table, which is a schema modification that is reversible (the table can be dropped). While it alters the database structure, it does not execute arbitrary queries, delete data, or trigger external operations. It falls under Write category as a schema creation action.

From the tool's definition Tool description states it 'Initializes the base \'records\' table in the specified database.' Initialization creates and sets up a table structure, which modifies database schema.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

init_schema Rate-limited

init_schema 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": {
    "init_schema": {
      "limits": [
        {
          "counter": "init_schema_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 Pg Mnemosyne, so you can run agents against it safely.

FAQ

Questions about init_schema

What does the init_schema tool do? +

Initializes the base 'records' table in the specified database. It is categorised as a Write tool in the Pg Mnemosyne MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on init_schema? +

Register the Pg Mnemosyne MCP server in PolicyLayer and add a rule for init_schema: 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 Pg Mnemosyne. Nothing to install.

What risk level is init_schema? +

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

Can I rate-limit init_schema? +

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

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

init_schema is provided by the Pg Mnemosyne MCP server (janadasroor/pg-mnemosyne-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.