Two gaps stood between the module UI contract and a host that could use
it. ADR 0023 recorded the first honestly but never diagnosed it: a module
UI file compiled with `"types": []` could still typecheck `process.env`.
The second was simply missing — nothing imported a compiled artifact,
checked its identity, mounted it, or tore it down.
The leak was one type-only import, bisected against the real type graph
rather than guessed. `@ekklesia/module-ui-sdk` imported
`type { EkklesiaPrincipal } from "@ekklesia/contracts"`. Importing
contracts/identity alone is clean and importing Zod alone is clean, but
contracts exposes a single barrel entry, so that one import reached
module-database, whose Drizzle types re-introduce Node's globals. The
runtime was never affected — the import was erased and host-context.js is
`export {}` — but a type-graph leak is still a real boundary failure,
because it silently permits code that cannot run in its target
environment.
The fix is not a narrower import path. The SDK now has no dependencies at
all, so there is no graph to leak through and no future contracts change
can reopen this. It owns `ModuleUiPrincipal`: the same shape ADR 0022
chose, with the Zod brand dropped. That brand encodes a server-side
parsing guarantee a browser cannot produce, and it is the same reason
`permissions.has` already took a plain string. An Ekklesia host still
passes its own `EkklesiaPrincipal` straight through — a branded string is
assignable to `string` — while a standalone host builds the literal.
Proven the way an author experiences it: two fixtures compiled under the
exact project a module uses, one supported and one deliberately reaching
for `process`, with the second required to fail on that specific name.
`@ekklesia/module-ui-host` is the generic loader, in its own package
because the SDK is bundled into every module artifact and host-only
loader code has no business shipping there. The boundary checker enforces
both directions: modules may not depend on the loader, and the loader may
depend only on the SDK plus dev-time tooling.
The distinction that shaped the design: Core resolves `entrypoints.ui` to
an absolute path on the server's disk, and a browser needs a URL. A
loader that accepted the path would test green on a server and fail in
every real host, and would quietly own asset publication. So the loader
takes a browser-loadable URL and knows nothing about how one is obtained.
Ekklesia has no route that publishes installed artifacts, so this is
precisely: loader complete, publication deferred. Nothing can mount an
installed module UI yet, and the docs say so rather than implying
otherwise.
Dynamic import is `(url) => import(url)` with a non-analyzable specifier,
kept as a runtime import so a host does not statically bundle every
installed module or need a hardcoded registry. It is injectable for
bundlers needing their own escape hatch, and deliberately not `eval` or
`new Function`, which would cost a host `unsafe-eval` in its CSP.
Identity is validated through the SDK's existing parser before `mount`
runs, so a stale or mismatched bundle never renders. Contract violations
propagate unwrapped; the loader adds only import and mount failure codes,
sanitized, with the cause attached. Unmount is idempotent, safe when a
module returned no cleanup, and marks an instance unmounted before
running cleanup so a throwing cleanup surfaces once and never re-runs. A
failed mount registers no cleanup. Each instance owns its own state, so
two mounts coexist. The loader never mutates the host's container — not
on success, failure, or unmount.
Tests prove all of it against real module URLs (`data:`, which both
browsers and Node import natively) rather than filesystem paths,
including one artifact built by the canonical Pass 2 pipeline and run
under both an Ekklesia-shaped and a standalone-shaped context. Core,
apps/api, and the contracts package are untouched; discovery remains
inert.
Co-Authored-By: Claude Opus 5 <[email protected]>
Architecture decision records
ADRs capture durable choices that affect more than one package or phase.
- Filenames use a four-digit sequence followed by a short kebab-case title.
- Status is
Proposed,Accepted,Superseded, orRejected. - Accepted ADRs are immutable except for status and cross-reference corrections.
- A changed decision receives a new ADR that links to and supersedes the old one.
Index
- 0001: Four-layer platform boundary — Accepted
- 0002: pnpm workspace and strict TypeScript — Accepted
- 0003: Development infrastructure — Accepted
- 0004: Replace unmaintained MinIO baseline — Accepted
- 0005: Static module manifests and atomic discovery — Superseded
- 0006: Versioned capabilities and compiled module runtime — Accepted
- 0007: Module-owned Drizzle schemas and table isolation — Accepted
- 0008: Module-owned migration contracts and offline validation — Accepted
- 0009: Transactional module migration execution — Accepted
- 0010: Core identity architecture and Better Auth adoption — Accepted
- 0011: Identity HTTP transport and public enrollment policy — Accepted
- 0012: Production-equivalent identity origin/CSRF protection under test — Accepted
- 0013: Core authorization, permission registry, and platform-owner bootstrap — Accepted
- 0014: Module permission declarations and platform permission registry — Accepted
- 0015: Static module HTTP routing and production runtime lifecycle — Accepted
- 0016: Module database access — Accepted
- 0017: Public request perimeter hardening — client address, signup gating, body limits, timeouts — Accepted
- 0018: Identity session resolution, canonical public origins, and PostgreSQL transport policy — Accepted
- 0019: Durable authorization history and grant management — Accepted
- 0020: Module runtime and migration execution hardening — Accepted
- 0021: Modules as independently hostable products — Accepted
- 0022: Module UI authoring model and host contract — Accepted
- 0023: Module UI build pipeline — Accepted
- 0024: Browser-safe module UI SDK and the generic host loader — Accepted