# startWebAuthnLoginWithId

Start a WebAuthn authentication ceremony by generating a new challenge for the user

Agent View of the PolicyLayer registry record for `startWebAuthnLoginWithId`. HTML page: https://policylayer.com/tools/io-fusionauth-mcp-api/startwebauthnloginwithid

## Facts

- Tool: `startWebAuthnLoginWithId`
- Server: Fusionauth (`@fusionauth/mcp-api`) — https://policylayer.com/tools/io-fusionauth-mcp-api.md
- Install: `npx -y @fusionauth/mcp-api`
- Homepage: https://github.com/FusionAuth/fusionauth-mcp-api
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "startWebAuthnLoginWithId",
    "arguments": {}
  }
}
```

## Why startWebAuthnLoginWithId is rated High

This tool executes an authentication ceremony startup operation rather than passively reading data. While it does not directly modify user data or have destructive effects, it triggers a state-changing operation (challenge generation) on the server that affects subsequent authentication flows.

From the tool's own definition: "Generates a new challenge for the user in a WebAuthn authentication ceremony; this is an active operation that initiates a cryptographic process with side effects (challenge creation/state change on the server)."

## Use case

AI agents invoke startWebAuthnLoginWithId to trigger actions in Fusionauth. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Fusionauth:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "startWebAuthnLoginWithId": {
      "limits": [
        {
          "counter": "startwebauthnloginwithid_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Fusionauth (313)

- `deleteAPIKeyWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteapikeywithid.md
- `deleteApplicationRoleWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteapplicationrolewithid.md
- `deleteApplicationWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteapplicationwithid.md
- `deleteConnectorWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteconnectorwithid.md
- `deleteConsentWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteconsentwithid.md
- `deleteEmailTemplateWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteemailtemplatewithid.md
- `deleteEntityGrantWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteentitygrantwithid.md
- `deleteEntityTypePermissionWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteentitytypepermissionwithid.md
- `deleteEntityTypeWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteentitytypewithid.md
- `deleteEntityWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteentitywithid.md
- `deleteFormFieldWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteformfieldwithid.md
- `deleteFormWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteformwithid.md
- `deleteGroupMembersWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletegroupmemberswithid.md
- `deleteGroupWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletegroupwithid.md
- `deleteIdentityProviderWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteidentityproviderwithid.md
- `deleteIPAccessControlListWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteipaccesscontrollistwithid.md
- `deleteJwtRefresh` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletejwtrefresh.md
- `deleteKeyWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletekeywithid.md
- `deleteLambdaWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletelambdawithid.md
- `deleteMessageTemplateWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletemessagetemplatewithid.md
- `deleteMessengerWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletemessengerwithid.md
- `deleteOAuthScopeWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteoauthscopewithid.md
- `deleteTenantWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletetenantwithid.md
- `deleteThemeWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deletethemewithid.md
- `deleteUserActionReasonWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteuseractionreasonwithid.md
- `deleteUserActionWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteuseractionwithid.md
- `deleteUserBulk` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteuserbulk.md
- `deleteUserLinkWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteuserlinkwithid.md
- `deleteUserRegistrationWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteuserregistrationwithid.md
- `deleteUserTwoFactorWithId` — Destructive — https://policylayer.com/tools/io-fusionauth-mcp-api/deleteusertwofactorwithid.md
- …and 283 more: https://policylayer.com/tools/io-fusionauth-mcp-api.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-fusionauth-mcp-api · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-fusionauth-mcp-api