retrieveUser

Retrieves the user by a verificationId. The intended use of this API is to retrieve a user after the forgot password workflow has been initiated and you may not know the user

SERVERFusionauth SOURCE@fusionauth/mcp-api

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

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

WHAT IT DOES

What retrieveUser does on Fusionauth

AI agents call retrieveUser to retrieve information from Fusionauth without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why retrieveUser is rated Low

This tool queries and returns user data based on a verificationId, which is a read-only operation. However, severity is elevated to 'medium' rather than 'low' because the retrieved user data may be sensitive (personally identifiable information, authentication state, etc.), and misuse could enable unauthorized access to user records or information disclosure—though the tool itself does not modify data or cause…

From the tool's definition Tool name is 'retrieveUser' and description states 'Retrieves the user' — a query operation with no side effects. The description explicitly describes it as retrieving data after a password reset workflow.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

retrieveUser Allowed

retrieveUser is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "retrieveUser": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

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

FAQ

Questions about retrieveUser

What does the retrieveUser tool do? +

Retrieves the user by a verificationId. The intended use of this API is to retrieve a user after the forgot password workflow has been initiated and you may not know the user. It is categorised as a Read tool in the Fusionauth MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on retrieveUser? +

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

retrieveUser is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit retrieveUser? +

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

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

retrieveUser 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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