ledger_ingest · Engram MCP: Risk & Policy

WHAT IT DOES

What ledger_ingest does on Engram

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

WHY IT NEEDS A POLICY

Why ledger_ingest needs a policy

This tool creates or modifies assertions in a persistent memory ledger, which is a reversible write operation. It does not execute arbitrary code, delete data irreversibly, or move financial resources.

From the tool's definition The tool description explicitly states 'Write an assertion to the ledger. Creates new or reinforces existing assertions.' The verb 'Write' and action 'Creates' directly indicate data modification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ledger_ingest Rate-limited

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

FAQ

Questions about ledger_ingest

What does the ledger_ingest tool do? +

Write an assertion to the ledger. Creates new or reinforces existing assertions. It is categorised as a Write tool in the 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 ledger_ingest? +

Register the Engram MCP server in PolicyLayer and add a rule for ledger_ingest: 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 ledger_ingest? +

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

Can I rate-limit ledger_ingest? +

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

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

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