update_memo · Memos MCP: Risk & Policy

WHAT IT DOES

What update_memo does on Memos

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

WHY IT NEEDS A POLICY

Why update_memo needs a policy

The update_memo tool modifies data (memos) in a reversible manner - updates can be undone by subsequent updates or restores. This makes it Write category rather than Destructive. Severity is medium because unintended modifications to memos could cause data corruption or loss of intended content, but the effect is reversible and the blast radius is limited to memo data.

From the tool's definition Tool name 'update_memo' combined with server description stating it 'Enables AI assistants to create, read, update, delete, and list memos' indicates this tool modifies existing memo data reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_memo Rate-limited

update_memo 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": {
    "update_memo": {
      "limits": [
        {
          "counter": "update_memo_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 Memos, so you can run agents against it safely.

FAQ

Questions about update_memo

What does the update_memo tool do? +

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

How do I enforce a policy on update_memo? +

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

What risk level is update_memo? +

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

Can I rate-limit update_memo? +

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

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

update_memo is provided by the Memos MCP server (mylxsw/memos-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.