retrieveRegistrationWithId

Retrieves the user registration for the user with the given Id and the given application 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/retrieveregistrationwithid.md

WHAT IT DOES

What retrieveRegistrationWithId does on Fusionauth

AI agents call retrieveRegistrationWithId 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 retrieveRegistrationWithId is rated Low

This tool queries and returns existing registration data associated with a user and application. It performs no mutations, deletions, or external operations. The blast radius of misuse is limited to unauthorized information disclosure about user registrations, which is a low-severity read-access violation.

From the tool's definition Tool name 'retrieveRegistrationWithId' and description 'Retrieves the user registration' indicate a data retrieval operation with no modification or side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

retrieveRegistrationWithId Allowed

retrieveRegistrationWithId 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": {
    "retrieveRegistrationWithId": {}
  }
}

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 retrieveRegistrationWithId call is checked against it from then on.

FAQ

Questions about retrieveRegistrationWithId

What does the retrieveRegistrationWithId tool do? +

Retrieves the user registration for the user with the given Id and the given application 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 retrieveRegistrationWithId? +

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

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

Can I rate-limit retrieveRegistrationWithId? +

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

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

retrieveRegistrationWithId 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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