updateUserWithId

Updates the user with the given Id. OR Reactivates the user 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/updateuserwithid.md

WHAT IT DOES

What updateUserWithId does on Fusionauth

AI agents use updateUserWithId 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 updateUserWithId is rated Medium

This tool modifies user data (including account status like reactivation) reversibly. It does not delete data irreversibly, making it Write rather than Destructive. The severity is high because unauthorized user updates could grant unauthorized access, modify sensitive user profiles, or reactivate suspended accounts—significant blast radius in an identity management system like FusionAuth.

From the tool's definition Tool description states: 'Updates the user with the given Id. OR Reactivates the user with the given Id.' The verb 'Updates' and 'Reactivates' indicate modification of existing user records.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs updateUserWithId 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 updateUserWithId, this is the rule to start with:

updateUserWithId Rate-limited

updateUserWithId 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": {
    "updateUserWithId": {
      "limits": [
        {
          "counter": "updateuserwithid_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 updateUserWithId call is checked against it from then on.

FAQ

Questions about updateUserWithId

What does the updateUserWithId tool do? +

Updates the user with the given Id. OR Reactivates the user 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 updateUserWithId? +

Register the Fusionauth MCP server in PolicyLayer and add a rule for updateUserWithId: 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 updateUserWithId? +

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

Can I rate-limit updateUserWithId? +

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

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

updateUserWithId 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.

KEEP EXPLORING

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