accept_invite · Nexus Core MCP: Risk & Policy

WHAT IT DOES

What accept_invite does on Nexus Core

AI agents use accept_invite 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 accept_invite needs a policy

This tool creates or modifies data reversibly. Accepting an invitation changes the user's attendance status in a calendar system or event management backend, which is a Write operation. Severity is medium because misuse could cause embarrassment (accepting unwanted events, spam responses) or scheduling conflicts, but the action is reversible (can decline or cancel attendance later).

From the tool's definition Tool description states 'Respond accepted to an event invitation' — this modifies the state of an event by changing the user's RSVP status from pending to accepted.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

accept_invite Rate-limited

accept_invite 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": {
    "accept_invite": {
      "limits": [
        {
          "counter": "accept_invite_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 accept_invite

What does the accept_invite tool do? +

Respond 'accepted' to an event invitation. 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 accept_invite? +

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

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

Can I rate-limit accept_invite? +

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

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

accept_invite 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.