Loki

Vibe-code a real site. Schema and all.

Most AI builders one-shot a good-looking page. Loftur one-shots the whole thing over MCP: a real content schema (models, fields, a typed GraphQL + schema API — feature-compatible with DatoCMS, minus the CRUD-UI), a per-site database, routes, islands, and server functions. Then the owner hands editors a scoped MCP token to maintain content and upload images — no schema changes, no code, no dashboard to babysit.

Loftur is a multi-tenant, agent-native site platform on Cloudflare, built on agent-cms (agent-first headless CMS) and Dynamic Workers (the Worker Loader API). Each site is its own isolated backend. Site code lives in the database, transpiles at write time, and runs in sandboxed V8 isolates loaded on demand — no repo, no bundler, no deploy step.

How it works

1. Sign up at loftur.app and claim {sub}.loftur.app. You get a one-time owner API key and a ready-to-paste MCP server config.
2. Point an AI agent (Claude Code or any MCP client) at {sub}.loftur.app/mcp with Authorization: Bearer <key>. The MCP endpoint also answers at loftur.app/mcp — it resolves your site from the key alone, so you can connect before the wildcard DNS resolves your subdomain.
3. The agent orients itself by calling site_help, then designs a content schema, a per-site feature database, routes, islands, and server functions — checking work with preview_site and shipping with publish_site.
4. The site serves at {sub}.loftur.app. Rollback is instant; a failed publish never touches the live site.

In blind tests, agents given nothing but the endpoint URL and a key discovered the tooling through site_help and shipped persistent apps — a guestbook and a poll — first try.

What the agent can build

Every site gets the full toolset over one merged /mcp endpoint (Loftur's own site tools plus every agent-cms tool, proxied in-process). Grouped:

Content schema & data (agent-cms). Content models, fields, records, publishing, assets, and search over a typed GraphQL + schema API — DatoCMS-style (allBlogPosts, blogPost(filter: …), BlogPostRecord, Structured Text as { value, blocks, inlineBlocks, links }). graphql_query explores the API (introspection included); schema_types returns live-generated TypeScript for every model.

A per-site feature database. For app state that isn't content (guestbooks, polls, orders), the agent designs relational tables at runtime with feature_migrate (named, idempotent, versioned migrations), inspects them with feature_schema / feature_query, and queries them from server code with Drizzle over env.FEATURES_SQL (drizzle-orm/sqlite-proxy + a featuresDriver(env) helper).

Routes, islands & server functions (no bundler). File-based routing under routes/; SSR Preact by default. Any component becomes a hydrated Preact island (<Island client="load|idle|visible">) served with native ES modules and import maps — no client bundle. Typed, validated serverFn server functions run in the sandboxed isolate, callable in-process from a loader and over RPC from an island. env.RECORDS.create does scoped record writes (gated by loki.config.json writableModels); env.REALTIME.publish fans out to WebSocket channels backed by a Durable Object.

Static & design assets. site_asset_import (by URL) and site_asset_write (base64) store files under public/, content-addressed in R2, served with ETag/304 and version-pinned.

npm dependencies — no install, no build. The agent can import any npm package. On site_write, Loftur resolves it via esm.sh, crawls and rewrites the module graph, snapshots a self-contained, version-pinned copy into R2, then test-loads that snapshot in a throwaway workerd isolate to confirm it actually links and runs here. Support is empirical, not an allowlist: the write reports resolvedDeps with a loadable flag and rejects anything that needs a Node builtin or won't load. Server-only deps (inside a serverFn module) never reach the browser.

Byte-faithful versioning + an in-Worker shell. preview_site mints a 30-minute token that serves the draft at the real domain behind an HttpOnly cookie. publish_site validates every GraphQL document against the live schema, extracts the migration footprint, smoke-renders, and snapshots the authored source (plus compiled bundle and asset manifest) into an immutable version. rollback_site / site_versions / reset_site restore a version's exact source byte-for-byte. shell is a real in-process bash over the draft tree (grep/sed/awk/find/pipes) whose writes route through the same transpile + validate + dep-resolve pipeline as site_write.

Migration guard. Each published version records the set of GraphQL Type.field pairs it queries (its footprint). A destructive schema op that would break a live site is rejected with an error that teaches the expand → backfill → publish → contract order — over MCP and over the REST API (409). The safety CI would have given you, re-created where an agent can use it.

Owner vs editor

Two roles, resolved from the bearer token:

• Owner key — full access: schema, content, and code. This is the one-time key issued at signup.
• Editor token — content only. The owner mints one with create_editor_token; an editor points their own MCP client at it to create/update/delete records, publish, and upload images. It cannot touch the schema (models/fields) or the site's code. Manage with list_editor_tokens / revoke_editor_token.

The toolset is gated by an allowlist, so new tools default to owner-only.

Architecture

A single supervisor Worker (deployed as loki) serves the apex control plane, the merged /mcp endpoint, and every tenant site.

• Per-tenant isolation. Each site is its own backend in Durable Object SQLite, addressed by idFromName(siteId):

  • TenantDB holds the site's content and runs the agent-cms engine inside the DO, against the DO's embedded SQLite (via SqlStorageD1, a ~50-line D1Database adapter over ctx.storage.sql — agent-cms runs unmodified).
  • TenantFeatureDB holds the site's feature data, separate so app table names can't collide with agent-cms's reserved tables.

  Name-addressing means no per-tenant binding ceiling (D1 static bindings cap out; DO namespaces scale to millions), idle cost ≈ $0 (hibernated DO = no compute billing), and 30-day point-in-time recovery per tenant for free.

• Worker Loader isolates. A tenant's published version loads into a V8 isolate via the Worker Loader (LOADER) — milliseconds cold, cached warm, globalOutbound: null. The isolate is handed its capabilities as WorkerEntrypoint service-binding stubs: GRAPHQL (loopback into that tenant's CMS), RECORDS, REALTIME, and FEATURES_SQL. This is not a convenience — a raw D1/DO handle cannot cross the loader's structured-clone boundary (DataCloneError); only entrypoint stubs pass. So the per-tenant DO SQLite is always reached through a capability stub, and the sandbox has exactly the surface a loader has and nothing more.

• Request routing. loftur.app / www → the control plane (signup, keys) and /mcp. {sub}.loftur.app → the tenant site (published version, or the draft under a preview cookie) and /mcp. A x-loftur-host header overrides the host for pre-DNS testing.

Local development

Requires a Cloudflare account on Workers Paid (Worker Loader), pnpm, and wrangler logged in.

pnpm install
pnpm vendor                              # builds the site runtime shim (scripts/build-vendor.mjs)

wrangler d1 create loftur-db             # put the database_id into wrangler.jsonc (binding DB)
wrangler d1 migrations apply loftur-db   # applies migrations/ (add --remote for prod)
wrangler secret put WRITE_KEY            # any long random string (admin/default-site key)

pnpm dev                                 # wrangler dev
pnpm deploy                              # wrangler deploy

pnpm typecheck runs tsc --noEmit; pnpm types regenerates worker-configuration.d.ts via wrangler types (never edit it by hand). The Worker binds DB (D1 loftur-db), FEATURES_DB, LOADER (Worker Loader), ASSETS (R2), and the ChannelDO / TenantDB / TenantFeatureDB Durable Objects — see wrangler.jsonc.

See DECISIONS.md for the no-bundler architecture rationale (ADR-001) and the autonomous-run risk notes (ADR-002).

Status

Live at loftur.app: signup → keyed MCP → build, with a fully isolated content + feature backend per site. The apex, control plane, and loftur.app/mcp are in production; public serving at each {sub}.loftur.app needs the proxied wildcard *.loftur.app DNS record (serving is otherwise proven via the x-loftur-host override).

A note on the name. The project is being renamed loki → loftur ("Loftur" is the modern Icelandic form of Loptr, one of Loki's bynames — from loft = air/sky, an edge/cloud pun). The deployed Cloudflare Worker keeps the internal name loki and the runtime import namespaces stay loki/runtime and loki/schema — those are deploy/module names, never user-facing; renaming the Worker would strand its Durable Object data.

License

MIT © Jökull Sólberg