deleteWebAuthnCredentialsForUserWithId
Deletes all of the WebAuthn credentials for the given User Id.
This record as markdown: /tools/io-fusionauth-mcp-api/deletewebauthncredentialsforuserwithid.md
What deleteWebAuthnCredentialsForUserWithId does on Fusionauth
AI agents call deleteWebAuthnCredentialsForUserWithId to permanently remove resources in Fusionauth, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why deleteWebAuthnCredentialsForUserWithId is rated Critical
This tool permanently removes WebAuthn credentials, which cannot be undone without user re-registration. Deletion of authentication factors is a destructive action that could lock users out of their accounts or compromise security posture. The blast radius is significant if misused by an agent—deleting another user's credentials would be highly damaging.
From the tool's definition The tool description explicitly states it "Deletes all of the WebAuthn credentials for the given User Id." The verb "Deletes" and the irreversible nature of removing authentication credentials indicate a destructive operation.
Attacks that exploit this kind of access
The rule that runs deleteWebAuthnCredentialsForUserWithId 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 deleteWebAuthnCredentialsForUserWithId, this is the rule to start with:
deleteWebAuthnCredentialsForUserWithId is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect Fusionauth, apply this rule, and every deleteWebAuthnCredentialsForUserWithId call is checked against it from then on.
Questions about deleteWebAuthnCredentialsForUserWithId
Deletes all of the WebAuthn credentials for the given User Id. It is categorised as a Destructive tool in the Fusionauth MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Fusionauth MCP server in PolicyLayer and add a rule for deleteWebAuthnCredentialsForUserWithId: 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.
deleteWebAuthnCredentialsForUserWithId is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the deleteWebAuthnCredentialsForUserWithId 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 deleteWebAuthnCredentialsForUserWithId. 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.
deleteWebAuthnCredentialsForUserWithId 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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