memento_pmg_add_relation · Memento MCP: Risk & Policy

WHAT IT DOES

What memento_pmg_add_relation does on Memento

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

WHY IT NEEDS A POLICY

Why memento_pmg_add_relation needs a policy

This tool creates or adds relational data between entities in Memento's SQLite temporal graph without irreversibly deleting data. The predicates (depends_on, blocks, implements) suggest graph structure modifications. While potentially concerning in a system that enforces goals/coercion, the core action is Write (reversible data creation).

From the tool's definition Tool name includes 'add' and description states 'Add a relation between entities' — creates new data (relational links) in the temporal graph. Marked [DEPRECATED] suggests it modifies stored state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

memento_pmg_add_relation Rate-limited

memento_pmg_add_relation 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": {
    "memento_pmg_add_relation": {
      "limits": [
        {
          "counter": "memento_pmg_add_relation_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 Memento, so you can run agents against it safely.

FAQ

Questions about memento_pmg_add_relation

What does the memento_pmg_add_relation tool do? +

[DEPRECATED] Add a relation between entities. Predicates: depends_on, blocks, implements,. It is categorised as a Write tool in the Memento MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on memento_pmg_add_relation? +

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

What risk level is memento_pmg_add_relation? +

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

Can I rate-limit memento_pmg_add_relation? +

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

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

memento_pmg_add_relation is provided by the Memento MCP server (joyciakira/memento). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.