createDeviceUserCode
Retrieve a user_code that is part of an in-progress Device Authorization Grant. This API is useful if you want to build your own login workflow to complete a device grant. OR Retrieve a user_code that is part of an in-progress Device Authorization Grant. This API is useful if you want to build yo...
This record as markdown: /tools/io-fusionauth-mcp-api/createdeviceusercode.md
What createDeviceUserCode does on Fusionauth
AI agents call createDeviceUserCode 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.
Why createDeviceUserCode is rated Low
Despite the 'create' prefix in the name, the description clearly states this tool retrieves (reads) an existing user_code from an in-progress Device Authorization Grant. The tool does not create or modify data; it fetches an existing code. Severity is low as it only retrieves a code that is already part of an active flow, though it does require an API key, suggesting some sensitivity.
From the tool's definition 'Retrieve a user_code that is part of an in-progress Device Authorization Grant'
Attacks that exploit this kind of access
The rule that runs createDeviceUserCode 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 createDeviceUserCode, this is the rule to start with:
createDeviceUserCode is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Fusionauth, apply this rule, and every createDeviceUserCode call is checked against it from then on.
Questions about createDeviceUserCode
Retrieve a user_code that is part of an in-progress Device Authorization Grant. This API is useful if you want to build your own login workflow to complete a device grant. OR Retrieve a user_code that is part of an in-progress Device Authorization Grant. This API is useful if you want to build your own login workflow to complete a device grant. This request will require an API key. It is categorised as a Read tool in the Fusionauth MCP Server, which means it retrieves data without modifying state.
Register the Fusionauth MCP server in PolicyLayer and add a rule for createDeviceUserCode: 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.
createDeviceUserCode is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the createDeviceUserCode 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.
Set action: deny in the PolicyLayer policy for createDeviceUserCode. 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.
createDeviceUserCode 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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