createFormFieldWithId
Creates a form field. You can optionally specify an Id for the form, if not provided one will be generated.
This record as markdown: /tools/io-fusionauth-mcp-api/createformfieldwithid.md
What createFormFieldWithId does on Fusionauth
AI agents use createFormFieldWithId 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.
Why createFormFieldWithId is rated Medium
This tool creates (writes) form field data reversibly. It does not delete data (not Destructive), execute arbitrary code (not Execute), move money (not Financial), or retrieve existing data (not Read). The medium severity reflects that misconfiguration could affect application forms and user experience, but the blast radius is limited to form metadata rather than user data deletion or financial impact.
From the tool's definition Tool description states 'Creates a form field' — an explicit write operation that generates or modifies form configuration data. The optional Id parameter allows specification of the field identifier.
Attacks that exploit this kind of access
The rule that runs createFormFieldWithId 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 createFormFieldWithId, this is the rule to start with:
createFormFieldWithId 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Fusionauth, apply this rule, and every createFormFieldWithId call is checked against it from then on.
Questions about createFormFieldWithId
Creates a form field. You can optionally specify an Id for the form, if not provided one will be generated. 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.
Register the Fusionauth MCP server in PolicyLayer and add a rule for createFormFieldWithId: 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.
createFormFieldWithId is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the createFormFieldWithId 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 createFormFieldWithId. 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.
createFormFieldWithId 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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