db_maintenance · Engram MCP: Risk & Policy

WHAT IT DOES

What db_maintenance does on Engram

AI agents invoke db_maintenance to trigger actions in Engram. 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 db_maintenance needs a policy

This tool executes database maintenance operations (integrity check and WAL checkpoint). The WAL checkpoint consolidates the write-ahead log into the main database file, which is a system-level operation with side effects on database internals. While not destructive in the data-deletion sense, it actively modifies the database file structure and is not a simple read.

From the tool's definition 'Ejecuta mantenimiento en la base de datos SQLite: integrity_check para detectar corrupción y wal_checkpoint para consolidar el WAL al archivo principal' — runs database maintenance operations including WAL checkpoint which modifies database internals

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_maintenance Rate-limited

db_maintenance 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": {
    "db_maintenance": {
      "limits": [
        {
          "counter": "db_maintenance_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 Engram, so you can run agents against it safely.

FAQ

Questions about db_maintenance

What does the db_maintenance tool do? +

Ejecuta mantenimiento en la base de datos SQLite: integrity_check para detectar corrupción y wal_checkpoint para consolidar el WAL al archivo principal. Devuelve {integrity_ok, integrity_errors[], wal_checkpoint: {busy, log, checkpointed}}. It is categorised as a Execute tool in the Engram MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on db_maintenance? +

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

What risk level is db_maintenance? +

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

Can I rate-limit db_maintenance? +

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

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

db_maintenance is provided by the Engram MCP server (jacksini/engram-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.