retrieveUserWithId

Retrieves the user for the given Id.

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/retrieveuserwithid.md

WHAT IT DOES

What retrieveUserWithId does on Fusionauth

AI agents call retrieveUserWithId 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 retrieveUserWithId is rated Low

This tool fetches user data by ID without modifying, executing, deleting, or moving resources. It is a straightforward read operation. Severity is low because retrieval of user data has limited blast radius—the main risk is information disclosure, which depends on access controls and data sensitivity rather than the tool's inherent capability.

From the tool's definition Tool name 'retrieveUserWithId' and description 'Retrieves the user for the given Id' indicate a read-only query operation with no side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

retrieveUserWithId Allowed

retrieveUserWithId 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": {
    "retrieveUserWithId": {}
  }
}

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 retrieveUserWithId call is checked against it from then on.

FAQ

Questions about retrieveUserWithId

What does the retrieveUserWithId tool do? +

Retrieves the user for the given Id. 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 retrieveUserWithId? +

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

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

Can I rate-limit retrieveUserWithId? +

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

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

retrieveUserWithId 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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