# Architecture Blueprint — coulomb.social content & platform

| Field | Value |
|-------|--------|
| Status | **draft for discussion** (2026-08-12) |
| Product | coulomb.social rebuild (`coulomb-social`) |
| Related | stage-1 cut, capability model, content-substrate exploration |
| Non-goals | Final store vendor lock-in; implementing UI chrome in this doc |

## 1. Architectural aim

Deliver a co-creation product where:

1. **Identity** (users, groups, tenants) is **NetKingdom** — not reimplemented.
2. **Runtime** is **Railiance** — not reimplemented.
3. **User-owned content** is **markdown (+ assets)** that can be exported and reused without the app database.
4. The **database is a cache / projection** for cards, memberships, and speed.
5. **markitect-tool** enables efficient structured markdown (lib/service), not a product host.
6. **coulomb** owns co-creation UI (playing-card pages, spaces, transfer/copy) and product verbs.

## 2. Non-negotiable rules

| # | Rule |
|---|------|
| R1 | Markdown chunks (frontmatter + body + backmatter) + assets are the **exportable SoR** for content. |
| R2 | Postgres (or any app DB) holds **projections and app linkage only** for content; disposable for bodies. |
| R3 | Authn/IdP = **NetKingdom**; coulomb maps OIDC → Member; no password store. |
| R4 | Authz for product actions may compose NetKingdom groups, app membership, and content-plane ACLs — **no second user directory**. |
| R5 | **markitect-main** is legacy reference, not a runtime foundation. |
| R6 | **markitect-tool** is the markdown structure dependency (parse/validate/transform). |
| R7 | Content-plane choice (shard-wiki / kontextual / thin store) is behind a **narrow page-ops interface** so coulomb UI does not couple to federation or ECM graphs. |
| R8 | Stage-1 capability set remains: onboarding, spaces/pages with Title/Abstract/Visual, page copy, page transfer. |

## 3. System shape

```text
                         ┌──────────────────────────┐
                         │   NetKingdom             │
                         │   OIDC, groups, tenants  │
                         └────────────┬─────────────┘
                                      │ principal
                                      ▼
┌─────────────────────────────────────────────────────────────┐
│  coulomb.social (product)                                   │
│  • Card UI, spaces chrome, stage-1 product flows            │
│  • Session / Member / SpaceMembership projections           │
│  • PageOps façade: list/get/create/update/archive/copy/move │
│  • Railiance deploy (Helm, env, probes)                     │
└───────────────┬─────────────────────────────┬───────────────┘
                │                             │
                │ projections                 │ content ops
                ▼                             ▼
        ┌───────────────┐         ┌───────────────────────────┐
        │ App DB cache  │         │ Content plane (choose one │
        │ (Postgres)    │         │  primary adapter)         │
        └───────────────┘         │  A thin folder/git store  │
                                  │  B shard-wiki             │
                                  │  C kontextual-engine      │
                                  └─────────────┬─────────────┘
                                                │ structure
                                                ▼
                                  ┌───────────────────────────┐
                                  │ markitect-tool            │
                                  │ front/body/back, schema   │
                                  └───────────────────────────┘
                                                │
                                  ┌─────────────▼─────────────┐
                                  │ Asset bytes (see §6)      │
                                  │ content-addressed blobs   │
                                  └───────────────────────────┘
```

**Product verbs (PageOps)** — store-agnostic:

| Op | Meaning |
|----|---------|
| `list_pages(space)` | Card projections |
| `get_page(id)` | Full markdown + resolved visual |
| `put_page(...)` | Create/update attributes + body |
| `archive_page` | Soft-delete / lifecycle |
| `copy_page` | Independent duplicate |
| `transfer_page` | Re-home to another space |
| `put_visual` / `get_asset` | Binary visual/attachment |

Coulomb never talks to Forgejo/shard/kontextual APIs ad hoc from templates — only through PageOps.

## 4. Information model (product)

| Concept | Representation |
|---------|----------------|
| **Page** | Markdown document: frontmatter (title, abstract, visual ref, space, type, …) + body + backmatter (relations, provenance) |
| **Space** | Container context; may be a page of `type: space` or a first-class container id in frontmatter |
| **Visual** | Asset ref in frontmatter → blob/asset service |
| **Card** | UI projection: visual + title + abstract + actions (not a storage type) |
| **Member** | NetKingdom subject ↔ app Member row |
| **Tenant** | Instance / `tenant_id` (DR-1 C) |

## 5. Content-plane options (comparison)

### 5.1 Option A — Thin folder/git store + markitect-tool

| | |
|--|--|
| **Idea** | Layout of `.md` files + assets; optional git; markitect validates; app indexes cards |
| **Pros** | Fastest stage-1; trivial user export; low structure surface |
| **Cons** | Reimplements copy/transfer/versioning carefully; federation later is a rewrite |
| **When** | Need product velocity; content plane maturity unclear |

### 5.2 Option B — shard-wiki (thin slice)

| | |
|--|--|
| **Idea** | Headless wiki orchestration; pages as union of shards; IdP external; coulomb = UI |
| **Pros** | Built for wiki pages, git coordination, overlays, multi-shard (personal + space); INTENT names Coulomb; no UI ownership |
| **Cons** | Early product maturity for multi-tenant ops; federation API can over-structure if not sliced thin |
| **When** | Want page federation / export shards / git-addressable coordination as first-class |
| **Thin-slice rule** | One InformationSpace per instance; one primary shard; hide federation from card UI |

### 5.3 Option C — kontextual-engine (knowledge ops / CMS-ECM backend)

| | |
|--|--|
| **Idea** | Headless knowledge operations: durable **KnowledgeAsset** identity, representations, metadata, relationships, workflows, audit, blob storage, optional CMIS; markdown via markitect-tool adapter |
| **Pros** | Strong identity for assets beyond path; lineage, versioning, export packages, multi-format future; **blob layer already implemented** (memory/fs/S3, content-addressed); PolicyGateway port ready for external authz; aligns with “ECM without being the UI” |
| **Cons** | Heavier than pure wiki; **not streamlined for NetKingdom** today (actors are engine-local; default `AllowAllPolicyGateway`); markdown is *a* format among many — SoR discipline must force “source representation is markdown file users can take” |
| **When** | Need governed asset registry, visuals/blobs, audit, multi-format, CMIS-ish interoperability; willing to invest PolicyGateway → flex-auth / NetKingdom |
| **Auth gap** | `Actor` + `external_ref` can map to OIDC subject; `PolicyGateway.authorize` must call **flex-auth** (or equivalent) with NetKingdom groups — not reimplement IAM inside kontextual |

**kontextual already has (relevant):**

- Asset registry (create, metadata, lifecycle, versions, relationships, audit)
- BlobStorage port + local/S3/memory adapters, dedupe by sha256
- Representation kinds (source / normalized / derived)
- markitect-tool reuse boundary docs + adapter package
- Service API surface for assets/retrieval/workflows
- Policy port (pluggable); default allow-all for tests

**kontextual does not yet have (for coulomb):**

- First-class “space + card product model”
- Wired NetKingdom / KeyCape session → Actor
- Production flex-auth policy adapter
- Guaranteed “markdown file tree export is the happy path” product packaging (export exists as concept; productize for coulomb)

### 5.4 How options relate (not exclusive forever)

```text
coulomb PageOps
    │
    ├─ short term: A or thin B/C adapter
    │
    └─ adapters can evolve:
         folder/git shard  ──► shard-wiki InformationSpace
         markdown assets   ──► kontextual KnowledgeAsset + BlobStorage
         markitect-tool    ──► always structure layer
```

shard-wiki optimizes **wiki federation and page union**.  
kontextual optimizes **governed multi-format knowledge assets + blobs + audit**.  
coulomb optimizes **co-creation product**.  

A hybrid is possible later: shard-wiki as page navigation plane, kontextual as asset/blob + governance — only if spikes show value without double-structure tax.

## 6. Asset management — extract to its own repo?

### 6.1 What exists today

| Source | Asset story |
|--------|-------------|
| **kontextual-engine** | Clean **BlobStorage** protocol + content-addressed store + representation linkage; small, intentional, portable adapters (~memory/fs/S3) |
| **markitect-main** `markitect/assets/` | Large (~0.5M+ tree) manager/registry/packager/optimizer/analytics — **orphan** in succession map; do not run coulomb on it |
| **coulomb** | No first-class visual/blob store yet (stage-1 Visual is todo) |

### 6.2 Extraction thesis

**Yes, worth evaluating a dedicated `asset-store` (name TBD) capability** if:

1. **coulomb**, **kontextual**, **shard-wiki**, and future apps all need content-addressed bytes + metadata without pulling full ECM or full wiki.
2. The core contract is small: `put/get/stat/delete_unreferenced` + digest + media type + optional ACLs.
3. We want Railiance-wide reuse (space visuals, wiki attachments, kontextual representations).

**Prefer extracting from kontextual’s BlobStorage** (clean ports), **not** from markitect-main’s asset mega-package (mine ideas only: dedupe, mdpkg packaging).

### 6.3 Suggested extraction shape (discussion)

```text
asset-store (new repo or helix capability)
  ports: BlobStorage (digest-addressed)
  adapters: fs, s3, memory
  optional: reference accounting, GC, HTTP byte range
  NOT: full asset registry, workflows, CMIS, markdown parsing

kontextual-engine
  keeps KnowledgeAsset + Representation pointing at storage_ref
  depends on asset-store library/service

coulomb / shard-wiki
  may depend on asset-store for Visual without full kontextual
```

**Decision gate for extraction:** after coulomb stage-1 Visual needs a real store **and** a second consumer wants the same API. Until then, use kontextual blob adapters **in-process** or vendor the port as a small shared package without full service.

## 7. Identity & access control

```text
Browser → coulomb (session after NetKingdom OIDC)
                │
                ├─ product authz: SpaceMembership, tenant_id
                │
                └─ content plane actor:
                     Actor(external_ref=issuer|subject, groups=OIDC groups)
                     PolicyGateway → flex-auth (preferred) or engine rules
```

| Plane | Responsibility |
|-------|----------------|
| NetKingdom | Who is the user; groups/roles claims |
| coulomb | Session; Member; space membership product rules |
| flex-auth | Optional PDP for resource actions |
| Content plane | Enforce policy on get/put content; fail closed |

**Spike required:** map one OIDC login → kontextual `Actor` → deny-by-default policy for foreign tenant assets.

## 8. Deploy sketch (Railiance)

| Component | Deploy |
|-----------|--------|
| coulomb-social | Existing chart / app.coulomb.social |
| Content plane | Sidecar or separate service in `coulomb-social` ns or shared platform ns |
| asset bytes | PVC and/or S3-compatible; secrets via existing env-secret pattern |
| NetKingdom | Existing KeyCape / Authelia |

No apex DNS change until stage-1 cut.

## 9. ADR roadmap (proposed)

| ADR | Topic |
|-----|--------|
| ADR-0001 | NetKingdom identity (done) |
| ADR-0002 | Forgejo markdown binding (provisional slice → demote to adapter) |
| **ADR-0003** | Page-centric model + markdown SoR + DB cache (to write after spikes) |
| **ADR-0004** | Content-plane choice (A/B/C) + PageOps boundary |
| **ADR-0005** | Asset-store extraction (if/when) |

## 10. Spike checklist

See **[spike-checklist.md](./spike-checklist.md)** — executable evaluation tasks.

## 11. Discussion prompts

1. Is **user export as markdown tree** more important than **multi-format ECM** in the next 6 months? (Biases A/B vs C.)  
2. Do we need **multi-shard federation** (personal vault + space) at stage 1, or only later? (Biases B.)  
3. Should **Visual** block on asset-store extraction, or ship with kontextual/local blob first?  
4. Who owns **PolicyGateway** production adapter — coulomb, kontextual, or flex-auth team?  
5. Accept **hybrid**: kontextual for assets+registry, thin git for human-facing markdown tree sync?

## 12. Working recommendation (to debate, not freeze)

| Layer | Recommendation |
|-------|----------------|
| Product UI | coulomb cards + spaces |
| Markdown structure | markitect-tool |
| Identity / deploy | NetKingdom / Railiance |
| Content plane shortlist | Spike **B thin** and **C** in parallel; keep **A** as fallback |
| SoR narrative | User-facing SoR = markdown export; engine may add durable IDs/lineage **without** trapping content in opaque DB-only forms |
| Assets | Prefer kontextual BlobStorage now; extract **asset-store** when second consumer appears |
| markitect-main | Avoid |

---

## References

- `docs/architecture/2026-08-12-content-substrate-exploration.md`
- `docs/architecture/transclusion-and-chunks.md` — page-first model; chunks as extract/transclude
- `docs/architecture/authoring-modes-and-lazy-projections.md` — top-down/bottom-up; lazy Title/Abstractor/Visual + lock
- `docs/capability/stage-1-cutover.md`
- `docs/decisions/2026-08-12-feature-cut-stage-1.md`
- kontextual: `docs/architecture-blueprint.md`, `asset-registry-implementation.md`, `blob-storage-content-streaming-workplan.md`, `markitect-tool-reuse-boundary.md`
- shard-wiki: `INTENT.md`, `SCOPE.md`
- markitect-tool: `docs/markitect-main-scope-assessment.md`, `docs/transform-compose-include.md`, `docs/content-references.md`
- markitect-main succession: `docs/successor-gap-assessment.md`