fix: harden identity HTTP transport

docs/architecture/decisions/0011-identity-http-transport-and-public-enrollment.md

@@ -223,6 +223,16 @@ for an unrecognized origin does not prevent the server from processing the reque
 Auth's own origin/CSRF checks (below) independently protect state-changing calls regardless of
 CORS.
 
+> **Correction — see [ADR 0012](0012-identity-origin-csrf-protection-under-test.md).** The
+> paragraphs below describe what was verified and, honestly, not yet understood at the time this
+> ADR was accepted. ADR 0012 found the root cause of the Vitest non-reproduction described here
+> (the pinned Better Auth release silently skips its own origin/CSRF checks whenever `isTest()` is
+> true unless `advanced.disableOriginCheck` is explicitly set — Vitest's default `NODE_ENV=test`
+> triggers exactly that), fixed it by setting `advanced.disableCSRFCheck`/`disableOriginCheck`
+> explicitly to `false`, and added the automated coverage this ADR states does not exist. This
+> section is left as originally accepted, as the historical record; ADR 0012 is now authoritative
+> for this behavior.
+
 Better Auth's own CSRF/origin protections are untouched: `advanced.disableCSRFCheck` and
 `advanced.disableOriginCheck` are never set. Verified directly and repeatedly against the pinned
 release, through the real, compiled `apps/api` HTTP server (not just a direct `auth.handler()`

docs/architecture/decisions/0012-identity-origin-csrf-protection-under-test.md

@@ -0,0 +1,132 @@
+# 0012: Production-equivalent identity origin/CSRF protection under test
+
+- Status: Accepted
+- Date: 2026-07-21
+- Amends: [0011](0011-identity-http-transport-and-public-enrollment.md)
+
+## Context
+
+ADR 0011 stated that Better Auth's own server-side origin/CSRF rejection was real, verified
+production behavior, but could not be reproduced reliably under Vitest, and left the discrepancy
+undiagnosed rather than commit a flaky or misleading automated test. A follow-up corrective slice
+(`phase-4/identity-http-hardening`) revisited that gap, alongside four related hardening items
+found during the same review: Better Auth's default logger could emit raw exceptions and
+user-controlled input; the identity database pool had no bound on a hung query; `apps/api`'s
+shutdown had a narrow idempotency gap under concurrent callers; and the email/password length
+boundary was left on an implicit Better Auth default rather than an explicit one. This ADR covers
+only the origin/CSRF root cause and fix, since it is the one item that changes a previously
+documented architectural guarantee; the other four are implementation hardening, documented in
+[Identity](../../development/identity.md) and [API](../../development/api.md) rather than a new
+ADR.
+
+## Decision
+
+### Root cause: Better Auth silently disables origin/CSRF checking under a test runner by default
+
+Reading the pinned `[email protected]` release's own `create-context.mjs` directly:
+
+```js
+skipOriginCheck: options.advanced?.disableOriginCheck !== void 0
+  ? options.advanced.disableOriginCheck
+  : isTest() ? true : false,
+```
+
+`isTest()` (from `@better-auth/core/env`) is `nodeENV === "test" || toBoolean(env.TEST)`. Vitest
+sets `NODE_ENV=test` by default. So whenever `advanced.disableOriginCheck` is left unset — exactly
+Ekklesia's configuration before this ADR — Better Auth silently sets `skipOriginCheck: true` under
+Vitest and `false` in production: the identical code path behaves differently in the one place most
+important to verify it and the one place it actually matters. Better Auth's own
+`shouldSkipCSRFForBackwardCompat` then also skips CSRF validation whenever `skipOriginCheck` is
+`true` and `advanced.disableCSRFCheck` is left unset, coupling the two. This is Better Auth's own
+documented default, read from `isTest()` at Better Auth construction time — not a Vitest bug, a
+race condition, or anything specific to this repository's test harness. It explains ADR 0011's
+mystery well enough to act on: whatever precisely made that ADR's own `NODE_ENV`-forcing attempt
+unreliable (`isTest()` also honors a separate `TEST` environment variable, which a `NODE_ENV`
+override alone would not clear, and which Vitest or its surrounding tooling may set independently),
+an explicit `advanced.disableOriginCheck`/`disableCSRFCheck` value removes the `isTest()` branch
+entirely and cannot be affected by any test-runner environment variable.
+
+### Fix: pin both flags explicitly
+
+`core/src/identity/runtime.ts` now passes:
+
+```ts
+advanced: {
+  disableCSRFCheck: false,
+  disableOriginCheck: false,
+},
+```
+
+This removes the `isTest()` branch entirely — the flags are always explicit, so identical
+protection is enforced in every environment, including under Vitest. No other origin/CSRF-related
+option changes: `trustedOrigins` is still Phase 4A's single `IdentityConfig.trustedOrigins` list,
+cookies are still Better Auth's host-only defaults, and CORS is still the exact-match, no-wildcard
+policy ADR 0011 already established.
+
+### Automated coverage replaces the manual-only caveat
+
+`apps/api/tests/api-http.integration.ts` now asserts, against the real compiled server and a real
+PostgreSQL-backed session, all four scenarios ADR 0011 could previously only claim from manual
+verification:
+
+- A no-cookie first authentication attempt from a trusted browser origin succeeds.
+- A no-cookie first authentication attempt from an untrusted browser origin is rejected (`403`),
+  with no `Access-Control-Allow-Origin` header and no leaked internal detail in the body.
+- A cookie-bearing state-changing request (sign-out) from an untrusted browser origin is rejected
+  the same way, and — critically — the presented session remains valid afterward, proving the
+  rejected request never reached sign-out logic.
+- A denied origin never receives a permissive CORS header, in either of the above cases.
+
+The manual-reproduction paragraphs in ADR 0011 are left intact as the historical record of what was
+verified and not yet understood at the time; a short correction note there points here.
+
+### A narrower consequence: Fetch-API clients now need a trusted origin on sign-in/sign-up even without a cookie
+
+Enabling the checks surfaced a real, previously-untested distinction. Better Auth's first-login
+CSRF protection (`formCsrfMiddleware`, applied only to `/sign-in/email` and `/sign-up/email`) does
+not key off cookies alone: it also treats the presence of any `Sec-Fetch-*` header as evidence the
+caller is a Fetch-API client (browser or Node's own `fetch()`, which sends `Sec-Fetch-Mode: cors`
+automatically) and requires a trusted `Origin`/`Referer` in that case regardless of cookie
+presence. A previously-committed test claiming a *server-to-server* sign-up with no `Origin` header
+succeeds was actually exercising Node's `fetch()`, and once the check was genuinely enabled it
+correctly failed. The test now uses a raw `node:http` request (which sends no `Sec-Fetch-*`
+headers, matching curl and most backend HTTP client libraries) to prove the real claim: a *non-Fetch*
+server-to-server caller needs no `Origin` header; a Fetch-API caller (browser or Node's `fetch()`)
+does, on these two specific routes, cookie or not. See [API](../../development/api.md#origin-cors-and-cookies).
+
+### A related discovery: Better Auth's own transport dependency logs raw errors outside any logger option
+
+Verifying the logging hardening item from the same corrective slice against a real induced identity
+database failure surfaced a second, independent gap: `better-call` (the low-level HTTP dispatch
+library Better Auth is built on) has an unconditional `console.error("# SERVER_ERROR: ", error)`
+fallback for any error it does not recognize as a Better Auth `APIError`, which fires before Better
+Auth's own `logger` option is ever consulted. `core/src/identity/runtime.ts` now also sets
+`onAPIError: { throw: true }`, which lets Better Auth's own deliberate `APIError`s (wrong password,
+invalid origin, ...) resolve normally while routing genuinely unexpected failures out to Core's
+already-sanitized `handleAuthRequest` boundary instead. This is a logging fix, not an origin/CSRF
+one; the full account is in [API](../../development/api.md#logging).
+
+## Alternatives
+
+- Setting `NODE_ENV=production` inside the test process (as ADR 0011's own investigation already
+  tried) was not a viable fix even before the root cause was known: it is fragile (couples
+  unrelated behavior to a global environment variable inside the test runner) and, as this ADR's
+  investigation showed, does not actually address the mechanism — Better Auth reads the same
+  `isTest()` signal regardless, and pinning `NODE_ENV` inside the same process it already runs in
+  is not a meaningfully different configuration from leaving `advanced.disableOriginCheck` unset.
+- Leaving the gap as a documented manual-only guarantee (ADR 0011's original position) was rejected
+  once the root cause was known and fixable: an explicit, narrow configuration change closes it
+  completely, so there is no remaining reason to accept unverified production behavior.
+- Disabling Better Auth's built-in origin/CSRF checks and reimplementing origin validation directly
+  in `apps/api`'s CORS layer was rejected: it would duplicate a check Better Auth already performs
+  correctly once configured explicitly, and would weaken the cookie-bearing-request guarantee CORS
+  alone cannot provide (CORS is a browser-enforced, response-header mechanism; it does not stop a
+  request from being processed server-side).
+
+## Consequences
+
+Better Auth's origin/CSRF protection is now genuinely production-equivalent under the automated
+test suite, closing the gap ADR 0011 left open. Future changes to authentication endpoints can rely
+on `pnpm test:migrations:integration` to actually exercise this guarantee rather than requiring a
+separate manual verification pass. No route, response shape, cookie policy, or CORS behavior
+changed for any caller already sending a trusted `Origin` header.

docs/architecture/decisions/README.md

@@ -20,3 +20,4 @@ ADRs capture durable choices that affect more than one package or phase.
 - [0009: Transactional module migration execution](0009-transactional-module-migrations.md) — Accepted
 - [0010: Core identity architecture and Better Auth adoption](0010-core-identity-and-better-auth-adoption.md) — Accepted
 - [0011: Identity HTTP transport and public enrollment policy](0011-identity-http-transport-and-public-enrollment.md) — Accepted
+- [0012: Production-equivalent identity origin/CSRF protection under test](0012-identity-origin-csrf-protection-under-test.md) — Accepted