decline_invite · Nexus Core MCP: Risk & Policy

WHAT IT DOES

What decline_invite does on Nexus Core

AI agents use decline_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 decline_invite needs a policy

This tool performs a write operation by sending a response that modifies the state of an invitation in an external system. It is not destructive since the original invitation typically remains and can be acted upon differently. The blast radius is minimal - a declined invitation is a normal, easily-corrected action.

From the tool's definition Tool description states 'Respond declined with optional note' - this creates or modifies a response state in an external system (e.g., calendar invite, meeting request, group invitation).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

decline_invite Rate-limited

decline_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": {
    "decline_invite": {
      "limits": [
        {
          "counter": "decline_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 decline_invite

What does the decline_invite tool do? +

Respond 'declined' with optional note. 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 decline_invite? +

Register the Nexus Core MCP server in PolicyLayer and add a rule for decline_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 decline_invite? +

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

Can I rate-limit decline_invite? +

Yes. Add a rate_limit block to the decline_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 decline_invite completely? +

Set action: deny in the PolicyLayer policy for decline_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 decline_invite? +

decline_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.