add_participant · Bluebubbles MCP: Risk & Policy

WHAT IT DOES

What add_participant does on Bluebubbles

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

WHY IT NEEDS A POLICY

Why add_participant needs a policy

Adding a participant to a group chat creates a new association/relationship in the chat data structure. This is a write operation as it modifies existing data (the group's participant list) reversibly. The severity is medium because unauthorized addition could expose sensitive conversations to unintended parties and cause communication disruption, but the action is reversible (the participant can be removed).

From the tool's definition Tool description states 'Add a participant to a group chat', which modifies group membership by adding a member. This is a reversible modification (participants can be removed later).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_participant Rate-limited

add_participant 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": {
    "add_participant": {
      "limits": [
        {
          "counter": "add_participant_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 Bluebubbles, so you can run agents against it safely.

FAQ

Questions about add_participant

What does the add_participant tool do? +

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

How do I enforce a policy on add_participant? +

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

What risk level is add_participant? +

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

Can I rate-limit add_participant? +

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

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

add_participant is provided by the Bluebubbles MCP server (metaember/bluebubbles-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.