[FEATURE] Trusted devices: support multiple concurrently enrolled FIDO2 authenticators (currently single-enrollment, replace-only)

Preflight

• Searched existing issues. #81550 covers the enrollment prompt crashing on click; no existing issue covers multiple authenticators.
• As of 2026-07-28, "passkey" returns zero results on support.claude.com and the feature is absent from release notes through July 24. The feature's UI name appears to be Trusted devices (claude.ai/settings/account#trusted-devices).
• Current behavior below was confirmed by Fin (Anthropic's support AI agent) on 2026-07-28; a parallel escalation to a human agent has been requested through support.

Summary

Claude Desktop for Windows (MSIX) recently began offering passkey enrollment at sign-in. I enrolled successfully using a hardware FIDO2 security key (resident/discoverable credential, verified present on the key).

Per Fin, enrollment is single-device / replace-only: to use a second authenticator, I must remove the currently trusted device at Settings > Account > Trusted devices and re-enroll with the other key at next sign-in. Between full sign-ins, biometric step-up (Windows Hello / Face ID / Touch ID) refreshes the session.

This makes a backup hardware key impossible in practice. A backup that must be pre-activated by disabling the primary is not a backup.

Request

1. Support multiple concurrently enrolled authenticators per account (primary + backup/travel key) — standard practice for hardware-key users and supported by every major relying party (Google, GitHub, Microsoft).
2. Provide a credential management UI: list, rename, and revoke individual enrolled authenticators, not only whole-device removal.
3. Publish documentation. The login article (13189465) still describes only Google and email-link sign-in; "Trusted devices" and the passkey prompt are undocumented.

Additional pain point: orphaned resident credentials

Because hardware-key enrollment writes a discoverable credential to the key itself, the remove-and-re-enroll swap orphans a resident credential on the removed key each cycle. It fails at sign-in and occupies one of the key's limited discoverable-credential slots until manually deleted via vendor tooling. Replace-only semantics multiply these over time.

Why it matters

• A single enrolled authenticator with no backup path creates lockout risk; the email magic link becomes the sole fallback.
• Hardware-key users specifically adopt the two-key pattern to survive loss, damage, and travel.
• Shipping enrollment ahead of multi-credential support, management UI, and docs leaves early adopters unable to follow FIDO2 best practice.

Environment

• Claude Desktop for Windows (MSIX), version: 1.24012.9.0
• Windows 11 Pro, version 25H2 (OS build 26200.8875)
• Authenticator: external hardware FIDO2 security key, USB

Related

• #81550 — passkey setup prompt after login reliably crashes Claude Desktop (same feature surface, filed 2026-07-27)