# Threat model The toolkit treats the public network, forwarding headers, request targets, cookies, credentials, and stored request records as untrusted. Application code, the configured trusted-proxy set, server filesystem permissions, and explicitly selected storage adapters are trusted. Controls include explicit proxy trust, bounded parsing, cryptographic request and session identifiers, digest-only session storage, Argon2id passwords, constant-time comparisons, same-origin and CSRF primitives, fail-closed storage errors, separate safe/sensitive analytics projections, organization-scoped bindings, single-use invitation digests, and short-lived audited break-glass grants. Passkey ceremonies require one exact HTTPS origin and relying-party ID, discoverable credentials, user verification, and single-use random challenges. The SQLite adapter consumes enrollment tokens and ceremonies atomically. Operation approvals retain a separate digest of canonical application state; the random WebAuthn challenge is never replaced by a predictable state hash. Cross-origin ceremonies, unsupported credential algorithms, expired state, and binding drift fail closed. Signature-counter clone warnings are surfaced for audit but do not automatically lock out multi-device passkeys whose counters legitimately remain zero. An application may create an account with a cryptographically generated temporary credential and `RequirePasswordChange`. Successful rotation compares the current credential, replaces its Argon2id hash, clears the requirement, and revokes every session in one repository transaction. The application must restrict such a principal to password change and logout until rotation succeeds; the library does not infer route policy. Temporary credentials must be written to a private channel or mode-`0600` file and must never be printed into logs, manifests, process arguments, or deployment state. Administrative recovery is deliberately a separate capability. The storage adapter atomically replaces the credential, restores the password-change requirement, revokes all sessions, and appends a generic audit event. The core library does not expose a recovery HTTP handler, deliver the credential, or authorize the local operator. Applications must keep that command local, generate the credential cryptographically, and write it only to a newly created private file. A recovery must not reveal whether an account exists through a public request surface. Passkey-only recovery never creates a password or remote fallback. A local administrator revokes sessions and active ceremonies and issues a short-lived single-use enrollment token. Existing passkeys remain visible so the operator can review and remove lost credentials after enrolling a replacement. The library prevents remote removal of the final credential; applications should require a freshly bound passkey assertion before every removal. Unsafe methods without an exact Origin or trustworthy same-origin Fetch Metadata fail the origin check. Authentication middleware fails closed when its service or `__Host-` cookie policy is invalid. Imported request records have bounded byte and duration fields before analytics sums them. The toolkit does not sandbox application handlers, secure an incorrectly configured reverse proxy, authorize application routes automatically, encrypt a compromised host, or decide how long an operator may lawfully retain personal request evidence. Optional account mail treats email links as bearer secrets, not sessions or MFA. `authmail` binds random single-use digests to account identity, purpose, current credential and expiry. Address changes additionally require current password, session and both mailboxes. Reset requires an already verified current mailbox; success creates no login and removes no enrolled factor. The SQLite adapter atomically rechecks authority, revokes sessions/grants and queues notices with the audit. Existing ownership and financial records are not reassigned. SMTP authenticates only after verified TLS with no plaintext fallback. Encrypted outbox payloads require an application-owned key, which may itself be wrapped in SQLite only when its external wrapping key is kept separately. Compromise of the sender, recipient mailbox or application host remains a threat. SMTP DATA acceptance is not inbox delivery and crash retries are not exactly once. Forms, CSRF/origin enforcement, fragment-to-POST handling, IP/concurrency limits and non-enumerating responses remain explicit consumer responsibilities; see the [integration boundaries](../authmail/README.md). Applications must pass the authenticated user and requested resource hierarchy to `access.Authorize`; possessing a platform-level `auth` role does not bypass that decision. Team membership is resolved by the repository rather than accepted from request input. Break-glass access lasts at most one hour and is not a substitute for ordinary role policy. Local storage adapters assume the parent directory and host account are trusted. They reject a symlink at the configured final path and apply bounded file modes, but they do not defend against a concurrent privileged actor replacing path ancestors during an open. The synchronous JSONL adapter deliberately favors durable, bounded evidence over maximum request throughput; the application owns rotation, retention, disk monitoring, and health escalation. Its default is mode `0600`; the sole wider option is mode `0640` for a deployment-assigned collector group. The toolkit does not select or change that group.