db_schema_update · Schema Engram MCP: Risk & Policy

WHAT IT DOES

What db_schema_update does on Schema Engram

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

WHY IT NEEDS A POLICY

Why db_schema_update needs a policy

The 'update' operation modifies existing schema records in the persistent SQLite store. This is a Write category action because it creates or modifies data reversibly—schema updates can be undone by saving a different version or deleting and re-creating entries.

From the tool's definition Tool name 'db_schema_update' indicates modification of stored schema data. The server stores 'table structures and metadata in a local SQLite file,' and sibling tools include db_schema_delete, db_schema_get, db_schema_list, and db_schema_save, establishing…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_schema_update Rate-limited

db_schema_update 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": {
    "db_schema_update": {
      "limits": [
        {
          "counter": "db_schema_update_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 Schema Engram, so you can run agents against it safely.

FAQ

Questions about db_schema_update

What does the db_schema_update tool do? +

db_schema_update. It is categorised as a Write tool in the Schema Engram MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on db_schema_update? +

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

What risk level is db_schema_update? +

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

Can I rate-limit db_schema_update? +

Yes. Add a rate_limit block to the db_schema_update 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_schema_update completely? +

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

db_schema_update is provided by the Schema Engram MCP server (wabox32/schema-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.