create_reminder · Nexus Core MCP: Risk & Policy

WHAT IT DOES

What create_reminder does on Nexus Core

AI agents use create_reminder 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 create_reminder needs a policy

This tool creates a new reminder entry in the system, which is a reversible write operation. It does not delete, execute arbitrary code, move money, or have destructive side effects. The blast radius is minimal—a mistaken reminder is easily deleted or ignored. Severity is low because reminder creation is benign even if misdirected by an agent.

From the tool's definition Tool name is 'create_reminder' and description states it creates a reminder with fire_at (datetime) and optional recurring parameters. The verb 'create' indicates data creation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_reminder Rate-limited

create_reminder 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": {
    "create_reminder": {
      "limits": [
        {
          "counter": "create_reminder_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 create_reminder

What does the create_reminder tool do? +

Create a reminder. fire_at = ISO-8601 datetime. recurring optional (e.g. 'FREQ=DAILY'). 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 create_reminder? +

Register the Nexus Core MCP server in PolicyLayer and add a rule for create_reminder: 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 create_reminder? +

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

Can I rate-limit create_reminder? +

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

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

create_reminder 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.