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

# 0011: Identity HTTP transport and public enrollment policy

- Status: Accepted
- Date: 2026-07-21

## Context

ADR 0010 established Core's identity schema, Core-owned identity migrations, and a Better Auth
construction boundary, but deliberately stopped before exposing anything over HTTP: "no
authentication endpoint or UI exists yet." Ekklesia now needs a real, publicly reachable way for a
person to create an account and sign in, and a way for any Core/Surface/API code to resolve who
(if anyone) is making a given request.

This is also the first PR to make a product policy decision about *who* may hold an Ekklesia
identity and what that identity is worth. The project owner has been explicit: public registration
is intentional, a registered account is not a church-membership record, and the platform must not
let signup order or account creation itself grant any authority. Those decisions govern this ADR
as much as the technical transport choices do.

## Decision

### Public registration is an intentional product policy, not a placeholder

Anyone may create an Ekklesia account through email/password sign-up. Registration creates only an
**authentication identity** — a row proving "this email and password combination can prove control
of a session" — not a church-person record, a membership record, or evidence of attending,
volunteering, or belonging to the church in any way. A future church-person/profile model, not
Better Auth's `user` table, is where that domain data will eventually live, linked only through the
opaque `EkklesiaUserId` (ADR 0010).

### Every signup receives identical, lowest-privilege baseline status

Every account created through public registration receives the same thing: an authenticated
`EkklesiaPrincipal` carrying only its own opaque user ID. That status exists because being
authenticated is useful on its own — it is what will eventually let a signed-in person have
ownership-scoped personal features such as watch history, continue-watching state, saved content,
or preferences, all scoped to *their own* data. None of those features are implemented in this PR;
only the identity that will eventually carry them is. Baseline authenticated access is **not** an
administrative role, is not stored as a role/grant row (there is no role or grant system yet), and
is not distinguishable in storage from any other account beyond Better Auth's own required
`user`/`account` rows. It never grants Dashboard access, module-management access, staff or
volunteer-management access, or any media/event/form/roster/people-management permission — none of
that exists yet, and nothing in this PR creates a path toward an authenticated account acquiring it
implicitly.

**Signup order is never an authorization input.** No code path in this PR inspects how many users
already exist, branches on being the first account, or treats an empty database as special. The
first registered account and every account after it go through the exact same code path and
receive the exact same principal shape — proven directly by the test suite (see Testing). Platform
owner authority is not part of this schema at all: there is no `isAdmin`, `isOwner`, `isStaff`,
`isVolunteer`, `isMember`, role column, or admin plugin anywhere in this slice, because Core has no
authorization schema yet to grant such authority meaningfully. Platform-owner bootstrap is
deferred to Phase 4C, which must introduce an explicit, auditable, operator-invoked command that
grants an *existing* identity platform-owner authority — never an implicit consequence of being
first, and never a side effect of a public HTTP endpoint.

### Future authorization is deferred, and its shape is already distinguished

This PR does not implement authorization. It is written expecting Phase 4C (or later) to
distinguish, at minimum: public (unauthenticated) access; authenticated, self-scoped baseline
access (this PR); relationship-derived access (for example, a person added to a volunteer roster
automatically gaining narrowly scoped, reversible read access to that roster, which disappears the
moment the qualifying relationship ends — no unrelated or permanent elevation); explicit grants or
roles; and platform-owner authority. None of the last three exist yet. Relationship-derived access
in particular belongs to a future roster slice, not this one — it is a fundamentally different
mechanism (derived from a live domain relationship, not stored as a standing grant) and must not be
approximated here with a role field.

### Email/password is the only enabled provider, and why

`emailAndPassword: { enabled: true, disableSignUp: false, autoSignIn: false }` is the entire
authentication surface enabled in this slice. No social, OAuth/OIDC, passkey, magic-link, username,
OTP, or anonymous provider is enabled; no admin, organization, or two-factor plugin is enabled; no
custom user field, role field, or owner field is added to the schema. `autoSignIn: false` is
deliberate, not merely permitted: the pinned `[email protected]` release documents that setting
`autoSignIn: false` (like `requireEmailVerification: true`) activates its built-in **email
enumeration protection** — a duplicate sign-up returns the same `200` shape and a synthetic user
(`token: null`) instead of revealing that the email is already registered, and no second identity
row is created. This was verified directly against the pinned release, both by reading
`packages/better-auth/src/api/routes/sign-up.ts` and by exercising it against a live disposable
PostgreSQL database: a duplicate `/sign-up/email` call returns `200` with a fresh random `id` and
no second `ekklesia_core_user` row, while a first-time `/sign-up/email` call returns `200` with
`token: null` and **no session cookie is set**. A caller must call `/sign-in/email` explicitly
afterward to obtain a session. This is intentionally the *only* email-enumeration mitigation in
this slice; it is a Better Auth built-in, not new code.

Email verification and password recovery remain deferred **because no email delivery service
exists in this repository yet** — `sendResetPassword` and any verification-email sender are left
unconfigured. Consequently, **public registration is not ready for a real public launch** after
this PR: an account with a forgotten password has no recovery path, and an unverified email address
is trusted as entered. Both are explicitly out of scope here and are called out as follow-up work,
not silently accepted risk.

### Password policy

Better Auth's default password-length policy (`minPasswordLength: 8`, `maxPasswordLength: 128`) is
kept unmodified; this ADR does not deliberately justify a different bound. Passwords are hashed
with Better Auth's own `scrypt`-based hashing (its documented default) — Core never substitutes
custom cryptography.

### The Better Auth transport boundary hides Better Auth completely

`core/src/identity/runtime.ts` replaces Phase 4A's construction-proof-only factory (which returned
a discarded `{constructed: true}` marker) with `createIdentityRuntime`, now that a real HTTP
consumer exists. It returns a frozen `EkklesiaIdentityRuntime` exposing exactly two Fetch-standard
capabilities and nothing else:

- `handleAuthRequest(request: Request): Promise<Response>` — delegates directly to
  `auth.handler(request)`. Better Auth's own HTTP responses (including its 401s, 403s, and 422s)
  pass through completely unmodified; this is not rewritten into a second authentication protocol.
  Only a genuinely unexpected throw (not a normal Better Auth error response, which Better Auth
  itself already returns as a `Response`) is converted into a sanitized `IdentityRuntimeError`.
- `resolvePrincipal(headers: Headers): Promise<EkklesiaPrincipal>` — resolves the caller's
  `EkklesiaPrincipal`, described below.

Neither method, nor anything else reachable from `@ekklesia/core/identity`, exposes `auth.api`,
Better Auth's inferred user/session types, Better Auth's database models, the Drizzle adapter, the
raw database, a session token, cookie contents, a password hash, or Better Auth configuration.
Core's public barrel (`core/src/index.ts` → `core/src/identity/index.ts`) exports only
`createIdentityConfig`/`IdentityConfig` (ADR 0010), `createIdentityDrizzleDatabase` (ADR 0010, for
composing the database in the executable entry point), and `createIdentityRuntime`/
`EkklesiaIdentityRuntime`/`IdentityRuntimeError`. The Drizzle table objects
(`core/src/identity/schema.ts`) remain internal to `core/src/identity/`, reachable only by Core's
own code and tests — nothing outside Core needs them, since `createIdentityDrizzleDatabase` already
bakes the schema in.

**A resolved infrastructure failure must never look like "no session."** This is a genuine tension
with the pinned Better Auth release: `auth.api.getSession({headers})` is documented (and
source-verified) to catch every internal failure — including a downed database — and resolve to
`null`, exactly like a missing or expired session; it never throws. Left unmitigated, that would
mean a database outage during principal resolution would silently look identical to "nobody is
signed in," which is precisely the ambiguity this ADR is required to avoid. `resolvePrincipal`
therefore does not trust a `null` result unconditionally: when the incoming request carries **no**
`Cookie` header at all, Better Auth's own source never queries the database for that case (verified
in `packages/better-auth/src/api/routes/session.ts`), so `null` is unambiguous and is returned as
the anonymous principal immediately, at zero extra cost — this is the common case (most requests
carry no session cookie). Only when a `Cookie` header **is** present and `getSession` still returns
`null` — a genuinely ambiguous case, since it could mean an expired/malformed session *or* a
database that went unreachable partway through resolution — does `resolvePrincipal` run one small,
bounded (3-second) reachability probe (`select 1`) against the same injected database connection
before trusting the `null`. If the probe also fails, `resolvePrincipal` throws
`IdentityRuntimeError` with code `PRINCIPAL_RESOLUTION_FAILED` instead of returning the anonymous
principal, and the `/api/v1/principal` route converts that into a sanitized `503`, never a `200`
anonymous response. This is a deliberate, documented, imperfect mitigation — a small race window
remains between the probe and Better Auth's own lookup — not a claim of perfect detection; a future
slice could tighten it (for example, by tracking the underlying connection pool's own error state)
without changing this boundary's public shape.

### Ekklesia user ID and principal (extends ADR 0010)

`EkklesiaUserId` was, in Phase 4A, a plain Zod-validated `string` with no nominal typing —
confirmed by inspection before this PR began. It is now branded via Zod's `.brand<"EkklesiaUserId">()`:
a bare `string` is no longer assignable to `EkklesiaUserId` without passing through
`parseEkklesiaUserId`/`safeParseEkklesiaUserId`. The brand is type-system-only — it adds no runtime
wrapper, tag, or field, so a value still serializes as a plain opaque string (`JSON.stringify`,
string concatenation, and equality all behave exactly as before). Validation still asserts only the
constraints Ekklesia itself owns (non-empty after trimming, a generous 128-character upper bound)
and still does **not** assume any particular format. In particular it does not assume UUIDs: Phase
4A's schema stores `id: text("id").primaryKey()` with Better Auth's default *application-generated*
id mode, an opaque base62-style string, not a database-generated UUID — confirmed by inspecting
`core/src/identity/schema.ts` and the pinned Better Auth ID-generation documentation. Asserting a
UUID shape here would have been asserting something Ekklesia does not actually guarantee.

`EkklesiaPrincipal` (ADR 0010) is unchanged in shape: `{kind: "anonymous"}` or
`{kind: "authenticated", userId}`. This PR does not add email, name, image, email-verification
status, session ID, session expiry, session token, account/provider details, roles, permissions,
membership status, or volunteer relationships to it. The general principal stays exactly as narrow
as ADR 0010 defined it.

### HTTP surface

Better Auth is mounted at exactly `/api/auth/*` (`app.on(["POST", "GET"], "/api/auth/*", ...)`),
matching Better Auth's own documented Hono integration pattern. All Ekklesia-owned APIs live under
a versioned `/api/v1/*` namespace; this slice adds exactly one: `GET /api/v1/principal`, returning
the existing `EkklesiaPrincipal` contract as JSON (`{"kind":"anonymous"}` or
`{"kind":"authenticated","userId":"..."}`) with `Cache-Control: no-store` and a
`Vary: Origin, Cookie` response header. No generalized authorization middleware is added; there is
nothing yet for it to authorize.

### `apps/api` is a composition root and transport host, not a Surface

`apps/api` (workspace glob `apps/*` already existed per ADR 0002/repository-boundaries.md) owns
HTTP composition and process lifecycle. It depends on `@ekklesia/core`, `@ekklesia/contracts`,
`hono`, and `@hono/node-server` — Hono lives in the API application, never in Core, keeping Core
importable by any future transport without forcing an HTTP framework dependency on it.
`scripts/check-boundaries.ts`'s existing `apps-are-composition-roots` rule already forbids an app
from importing another app, a builder, or a module; it does not restrict `app → core`, so no
boundary-checker change was needed to let `apps/api` depend on `@ekklesia/core` directly. `app.ts`
exports a pure `createApiApp({runtime, trustedOrigins})` factory (no I/O, testable via `app.fetch`
directly with an injected fake runtime); `server.ts` separately exports a testable `startApi(config)`
composition function (constructs the database, the identity runtime, the app, and starts the real
HTTP listener, returning `{app, server, shutdown}`) and a process-level `main()` that only reads
environment variables, calls `startApi`, and wires `SIGINT`/`SIGTERM` to the returned `shutdown()`
— gated behind the same `isDirectExecution()` guard already used by `core/src/cli/doctor.ts`, so
importing `server.ts` (as tests do, to reach `startApi`) never starts a server or reads the
environment.

### The server never applies migrations

`apps/api` requires an already-migrated PostgreSQL database. It has no migration-discovery,
planning, or execution code at all — it only ever opens a Drizzle connection via Core's existing
`createIdentityDrizzleDatabase` (ADR 0010) and queries through it. There is no code path by which
starting the API creates the migration history table, creates the identity tables, or executes any
DDL. Operators must run `pnpm migrations:apply` first, exactly as ADR 0009 already requires for
every other Core or module migration.

### Origin, CORS, cookies, and CSRF

The API reuses Phase 4A's typed `IdentityConfig.trustedOrigins` as the single source of truth for
both Better Auth's own trusted-origin/CSRF checks and the API's CORS policy — there is no second,
competing origin configuration. `createApiApp`'s CORS middleware (`hono/cors`) uses a **function**
`origin`, not a static string or `"*"`: it reflects a request's `Origin` header back only when that
exact origin is present in the configured allowlist, and returns nothing (no CORS header at all)
otherwise. This is the safe, standard way to combine per-request dynamic origins with
`credentials: true` — the Fetch spec forbids `Access-Control-Allow-Origin: *` together with
`Access-Control-Allow-Credentials: true`, and Hono's own middleware does not enforce that
constraint for you, so an exact allowlist match (never a wildcard) is required here regardless.
CORS is applied to both `/api/auth/*` and `/api/v1/*`; only `GET`, `POST`, and `OPTIONS` and only
the `Content-Type` header are permitted, matching what these two routes actually need. A request
that legitimately carries no `Origin` header (native/server-to-server clients) is never blocked by
this CORS layer — CORS is a browser-enforced, response-header-only mechanism; omitting the header
for an unrecognized origin does not prevent the server from processing the request, and Better
Auth's own origin/CSRF checks (below) independently protect state-changing calls regardless of
CORS.

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()`
call) driven by a plain Node script: any non-`GET`/`HEAD`/`OPTIONS` request that carries a
`Cookie` header must also carry a trusted `Origin` (or `Referer`) header, or Better Auth itself
rejects it with `403 MISSING_OR_NULL_ORIGIN` (unrecognized origin: `403 INVALID_ORIGIN`) — a
`sign-out` call with a valid session cookie but an untrusted `Origin` is reliably rejected by
Better Auth itself, before this ADR's CORS layer is even involved, and the presented session
remains valid afterward since the rejected call never reaches sign-out logic. This is Ekklesia's
baseline, always-on CSRF guarantee for every cookie-bearing state-changing call, and it is real,
reproduced, production behavior of the pinned release running this exact code.

That guarantee is **not**, however, part of the automated `pnpm test:migrations:integration` suite.
While building this ADR, the identical scenario — same compiled server, same request sequence —
could not be made to reproduce reliably when driven through Vitest specifically: the rejection
silently does not fire, even in a single isolated test with its own fresh database and API
instance, and even with `NODE_ENV` forced to `"production"` inside the test process. The same is
true of Better Auth's documented stricter "first-login CSRF" check for email sign-in/sign-up
(validating `Origin`/`Referer` even before any cookie exists), which was also observed to stop
firing after several earlier sign-in/sign-up calls in the same process. Both were reproduced
correctly and repeatedly outside Vitest and were not pinned down to a documented, reproducible
cause inside the time available for this slice, so `apps/api/tests/api-http.integration.ts`
deliberately does not assert either behavior rather than commit a flaky or misleading automated
test — it documents the manual reproduction inline instead. What the automated suite does assert
is the layer this repository's own code owns end-to-end: CORS never returns
`Access-Control-Allow-Origin` for an untrusted origin, which is the actual browser-enforced
boundary. A future slice touching authentication endpoints should re-verify Better Auth's
server-side origin rejection directly (as this ADR did) before relying on it changing.

Cookies keep Better Auth's own defaults: `httpOnly: true` always, `sameSite: "lax"` always, and
`secure` driven by the configured `baseUrl`'s protocol (Better Auth treats an `https://` `baseURL`
as secure regardless of `NODE_ENV`). `advanced.crossSubDomainCookies` is not enabled and no cookie
`Domain` attribute is set, so every cookie remains host-only, matching ADR 0010's direction.
Trusted proxy headers (`advanced.ipAddress.trustedProxies`, `ipAddressHeaders`, or any
`X-Forwarded-*` trust) are not configured in this slice; a deployment behind a reverse proxy is
future work, and accepting spoofable forwarded headers without a proxy policy in place would be
worse than not trusting them at all.

### Rate limiting

Better Auth's built-in rate limiting is always enabled (`rateLimit.enabled: true`), including in
test/local composition — it is never disabled to make testing convenient. Its endpoint-specific
built-in rules (by default, a strict 3 requests per 10 seconds on every `/sign-in*` and `/sign-up*`
path) are preserved unmodified in production composition. Test composition alone may inject a
narrow, explicit `rateLimitOverride` (verified empirically to work via Better Auth's own
`rateLimit.customRules` targeting `/sign-in/email` and `/sign-up/email` specifically) so an
integration suite that legitimately issues many sign-in/sign-up requests in a short window is not
itself rate-limited; production composition (`apps/api/src/server.ts`'s `main()`) never sets this
override. Storage remains the default in-memory backend (`rateLimit.storage` unset). This has two
honest, documented limitations carried forward from ADR 0010's rate-limiting-adjacent guidance and
confirmed against the pinned release: it is **per-process**, so it provides no protection across
multiple API instances or restarts; and because no trusted-proxy IP policy is configured, Better
Auth may fall back to a single shared per-path bucket rather than a genuine per-client-IP bucket
when it cannot resolve a real client address. Neither limitation is solved by trusting spoofable
`X-Forwarded-*` headers, which this PR deliberately does not do. Public signup is therefore
rate-limited, but this is not yet the final, distributed, production-grade abuse-control design.

## Alternatives

- Letting the first registered account become an administrator automatically was rejected outright
  per explicit product direction: signup order must never be an authorization input, and Core has
  no owner capability to grant safely in this slice regardless.
- Adding an `isAdmin`/`isOwner`/role column now, "to be ready for" Phase 4C, was rejected: an unused
  authorization field invites exactly the kind of accidental elevation this ADR forbids, and Phase
  4C's bootstrap command is explicitly required to be an auditable operator action, not a schema
  default.
- Leaving `autoSignIn` at its default (`true`) was rejected: it would immediately grant a session
  (and disable Better Auth's built-in enumeration protection) on every signup, including duplicate
  attempts against an existing email, which is a weaker default than the one Better Auth itself
  documents for exactly this public-registration scenario.
- Trusting `getSession`'s `null` result unconditionally as "anonymous" was rejected: the pinned
  release's own source shows it swallows infrastructure failures, and the task's authorization
  ambiguity concern is real — a later authorization system consuming a falsely-anonymous principal
  during a database outage would be a silent security-relevant bug, not a graceful degradation.
- Enabling `advanced.ipAddress.trustedProxies`/`ipAddressHeaders` now, to give rate limiting a real
  per-client bucket, was rejected: there is no deployment proxy policy yet, and accepting forwarded
  IP headers without one would let any direct caller spoof its rate-limit bucket.
- A wildcard or reflect-any-origin CORS policy was rejected as incompatible with
  `credentials: true` per the Fetch specification, and as a direct violation of "allow only exact
  configured trusted origins."
- Reimplementing Better Auth's session validation directly against the identity tables (to sidestep
  the `getSession`-swallows-errors problem entirely) was rejected: it would create a second,
  divergent session-validation implementation alongside Better Auth's own, exactly the kind of
  duplicated authentication logic Core is meant to avoid.

## Consequences

A person can now publicly register, sign in, be resolved to an `EkklesiaPrincipal` by any code
holding the narrow Core identity runtime, and sign out — all while Better Auth stays fully
contained behind Core's contracts and Core stays fully unaware of Hono. Every account, first or
five-hundredth, is provably identical in privilege. What remains explicitly unavailable after this
PR: any role, permission, grant, or platform-owner capability; any relationship-derived access;
Dashboard, Website, or Mobile UI; email delivery, email verification, or password recovery; any
provider beyond email/password; and any deployment-proxy or TLS decision. The next expected slice
is Phase 4C: Core authorization (public / authenticated-baseline / relationship-derived / grants /
platform-owner), an explicit, auditable platform-owner bootstrap command, and the beginning of
reversible relationship-derived access — not a Dashboard Surface, which still depends on an
authorization model that does not exist yet.