updateMessengerWithId

Updates the messenger with the given Id.

SERVERFusionauth SOURCE@fusionauth/mcp-api

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-fusionauth-mcp-api/updatemessengerwithid.md

WHAT IT DOES

What updateMessengerWithId does on Fusionauth

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

RISK

Why updateMessengerWithId is rated Medium

The tool modifies existing messenger data by updating a resource identified by its ID. This is a reversible change (Write category) rather than deletion. High severity is appropriate because misconfigured messengers in an auth system could disrupt communication channels, affect user notifications, or impact account recovery flows.

From the tool's definition Tool name contains 'update' and description states 'Updates the messenger with the given Id' — a modification operation on messenger configuration.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs updateMessengerWithId safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Fusionauth, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For updateMessengerWithId, this is the rule to start with:

updateMessengerWithId Rate-limited

updateMessengerWithId 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": {
    "updateMessengerWithId": {
      "limits": [
        {
          "counter": "updatemessengerwithid_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Fusionauth, apply this rule, and every updateMessengerWithId call is checked against it from then on.

FAQ

Questions about updateMessengerWithId

What does the updateMessengerWithId tool do? +

Updates the messenger with the given Id. It is categorised as a Write tool in the Fusionauth MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on updateMessengerWithId? +

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

What risk level is updateMessengerWithId? +

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

Can I rate-limit updateMessengerWithId? +

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

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

updateMessengerWithId is provided by the Fusionauth MCP server (@fusionauth/mcp-api). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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