archive · Nexus Core MCP: Risk & Policy

WHAT IT DOES

What archive does on Nexus Core

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

WHY IT NEEDS A POLICY

Why archive needs a policy

The tool modifies metadata (folder/label state) of an existing message reversibly. It is not destructive (the message persists), not financial, not execute. The user can unarchive or restore the message, making it a Write operation. Low severity because the blast radius is limited to a single user's message organization with no side effects on other systems or data integrity.

From the tool's definition Archive action removes a message from INBOX but keeps the message (explicitly stated as reversible). This modifies message state/folder status without deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

archive Rate-limited

archive 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": {
    "archive": {
      "limits": [
        {
          "counter": "archive_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 Nexus Core, so you can run agents against it safely.

FAQ

Questions about archive

What does the archive tool do? +

Archive: remove from INBOX (keeps the message). It is categorised as a Write tool in the Nexus Core MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on archive? +

Register the Nexus Core MCP server in PolicyLayer and add a rule for archive: 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 Nexus Core. Nothing to install.

What risk level is archive? +

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

Can I rate-limit archive? +

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

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

archive is provided by the Nexus Core MCP server (noumenon-ai/nexus-core). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.