# TechnicalSpecificationDocument

Status: **draft scaffold** · Date: 2026-06-08

See InfoTechPrimers on coulomb.social for TSD conventions.

## 1. System Overview

Python package (`src/shard_wiki/`) implementing a federation orchestration
layer. Markdown-first, backend-neutral page model. Git-addressable coordination
per information space.

## 2. Implementation Stack

| Concern | Choice |
|---------|--------|
| Language | Python ≥ 3.11 |
| Layout | `src/` package, hatchling build |
| Tests | pytest |
| Lint/format | ruff |

## 3. Core Abstractions (to be specified)

| Abstraction | Description |
|-------------|-------------|
| Shard | Independently meaningful page store with sovereignty |
| Root entity | Joined information space shards attach to |
| Shard adapter contract | Versioned, capability-aware backend interface |
| Wiki page model | Paths, links, metadata, revisions |
| Projection | Lazy local view of remote content |
| Overlay | Non-destructive edit before remote mutation |
| Coordination journal | Git-backed change record |

## 4. Architecture References

- `spec/CoreArchitectureBlueprint.md` — whole-system architecture (layers, the dual narrow
  waist, the 15 capability spectra, projection, consistency); the normative source for §A.
- `spec/FederationArchitecture.md` — federation design (*what the union does*); §A is its
  companion (*what a backend must expose*).
- `spec/FederationRequirements.md` — yawex-derived ADRs (resolution, page model, overlay).
- `spec/ArchitectureBlueprint.md` — access, history, identity delegation (L5).

---

# A. Shard Adapter Contract (normative)

Deliverable of **SHARD-WP-0002** (T11–T16, T18): the versioned interface a backend implements
to participate as a shard, and the *normative* rules core relies on. It is the **bottom narrow
waist** (blueprint §6); the page model is the top waist (§7). This section is normative where it
says **MUST/SHOULD**; design rationale lives in the blueprint (cited, not restated).

## A.1 (T11) Capability model & versioned interface

- The contract is a **versioned interface** (`Foswiki::Store`/`Foswiki::Meta` is the proof a
  swappable-backend-behind-a-stable-interface works). A binding declares the contract version
  it implements; core checks compatibility at registration.
- **Operation verbs:** `read, write, diff, merge, lock, version, publish, notify,
  transclude-source, translate-syntax, structured-payload, derive-projection, execute`. The
  last two are **gated, OFF by default** (A.6/T18). Verb support is part of the profile and MUST
  reconcile with the T10 federation-ops matrix.
- **Capability profile = a position on each capability spectrum**, not a boolean checklist. The
  full set is the **fifteen spectra** (blueprint §6.1); operationally they reduce to a **small
  orthogonal core** (substrate, write-granularity, content-opacity, operational-envelope,
  access-grant, computational/liveness) with the rest **implied** via published rules that
  **forbid impossible profiles** (blueprint §6.5). Degradation reads only the **named
  axis-interaction subset** (blueprint §6.5 table) — that table *is* the degradation contract.
- A profile MUST express **absence** cleanly (the Oddmuse floor); core never guesses a missing
  capability.

## A.2 (T11/§6.6) Conformance — profiles are verified, not asserted

- The contract ships a **versioned conformance suite**. A binding is **admissible only if it
  passes**: the suite exercises each declared verb and spectrum position and checks observed
  behaviour matches the claim (a `write` round-trips, `notify` actually fires, an opaque shard
  refuses plaintext query, implied-position rules hold). A lying/buggy profile is **rejected at
  registration**, not run in production (blueprint §6.6).
- Conformance makes capability-as-data (I-3) and the §6.5 degradation contract **sound**.
  Mismatch is reported as a capability-by-capability diff; an adapter may register
  *degraded-but-honest* (drop the unsupported claim).

## A.3 (T14) Adapter binding — attachment-mode taxonomy

A backend MAY offer several modes; attach mode is a **per-binding, capability-gated choice**
with one declared authoritative (blueprint §6.3):

- **file-store** (native vault/folder *or* an interchange/sync mirror) · **git-IS-store** (forge
  wikis & ikiwiki — git is store *and* journal; the home case) · **in-engine-hosted** (XWiki
  component, Obsidian/Logseq/Roam plugin, Trilium script) · **local-REST** (Joplin Data API,
  Trilium ETAPI) · **external-API-only** (Notion) · **direct-DB** (MojoMojo schema→model) ·
  **CRDT-replica** (Anytype/AFFiNE/AppFlowy) · **P2P / no-central-endpoint**.
- **Backend-swap tolerance:** identity/provenance MUST survive a substrate change (bind to
  capabilities, not "it's files"). **Boundary:** an **image / live-memory blob is never an
  attach target** (I-12) — participation is export→files only.
- (UC-38, UC-40, UC-43, UC-50, UC-53, UC-57, UC-60, UC-62, UC-64, UC-65, UC-76, UC-79, UC-81.)

## A.4 (T12) Page model — structured / computational payload

The backend-neutral, Markdown-first page model MUST carry, without lossy flattening, every
shape in blueprint §7.1: prose; typed/computed records (incl. effective-vs-own computed
metadata); typed-graph statements (Wikibase); inline-embedded objects (Quip/Notion);
non-Markdown assets (typed asset / opaque blob / content-type registry); and the **four
computational shapes** (one-source-many-projections UC-83; notebook-with-embedded-output UC-84;
program-as-page; live/temporal). All reduce to `(content|source, structure, provenance
envelope, [derivation rule])`. **Identity is a stable handle; placement is separate; equivalence
is fingerprint-based** (blueprint §7.2, FederationRequirements ADR-01/02, I-9). The **provenance
envelope is layered** (page + span deltas; effective = page ⊕ delta, §7.3). (UC-34, UC-39,
UC-55, UC-58, UC-54, UC-44, UC-66, UC-67, UC-73, UC-83, UC-84.)

## A.5 (T13) History portability — adopt / supplement / import

Per the history axis: **adopt** git-native history as-is; **supplement** non-portable internal
history (DB / Notion / Joplin / Trilium revisions, CRDT-log) — the journal begins-now / mirrors
/ snapshots; **import** open file history (RCS, PlainFile, MojoMojo DB-version-rows) backfilled
preserving author/timestamp. **Partial/truncated history MUST be reported honestly** ("history
begins at", UC-24), never implied complete. Embedded-output documents (notebooks) use
paired-text (Jupytext) / cell-aware merge (nbdime). The space's own coordination history is the
event-sourced decision log (blueprint §8.1). (UC-36, UC-41, UC-24.)

## A.6 (T15) Syntax translation & content fidelity

Translation is a spectrum: **native → lossless → lossy-with-fidelity-report**. Read native
markup (TML, XWiki syntax, HTML) into the page model; accept Markdown overlays back via
**lossless bidirectional translation** where possible (Foswiki WysiwygPlugin is the proof). For
non-round-tripping models (Notion blocks, Trilium HTML, CRDT, typed-graph, notebook JSON/MIME):
translate lossily but **make the fidelity loss visible** — a per-shard/per-page report of what
projects cleanly vs degrades, with non-mappable elements preserved as provenance/sidecar (I-4).
Add a **structured-re-evaluable-value** point to the opacity spectrum (Wolfram expression).
Where no acceptable translation exists, the shard is a **read-only/projection** participant
(I-8), never silently corrupted. (UC-42, UC-59, UC-03, UC-73.)

## A.7 (T16) Addressing, identity & navigation

- **Span addressing:** adopt native span IDs where minted (Roam `:block/uid`, Logseq `id::`,
  Notion/CRDT UUID), shard-scoped so they survive projection and don't collide; else a
  position address (path+range) or content-fingerprint address. Portable tumbler is the ideal
  (blueprint O-6).
- **Transclusion** = one reference-not-copy primitive over the addressable union (FederationArch
  T8). **Query/navigation:** delegate to a shard's native query where capable (Datalog, DB
  query, XWQL, SPARQL), **else build a derived index over the projection** (Logseq pattern);
  dimensional/query-defined views are derived-tier. (UC-44–48, UC-51, UC-52, UC-54, UC-63,
  UC-74.)

## A.8 (T18) Computational / executable content capability

**In scope as a page-model + projection concern; out of scope as an execution platform**
(blueprint §8.5). Core **recognises** computational types, attaches the **canonical source**,
and presents derived forms as **provenance- and liveness-marked projections**. `derive-
projection`/`execute` are **gated capabilities, OFF by default**, carrying a **trust/sandbox**
concern, **degrading to a captured snapshot / static render / recording**. One snapshot-
provenance record (run id, source rev, timestamp, environment "unguaranteed") serves notebooks,
renders, recordings. No INTENT amendment required. (UC-54, UC-55, UC-83, UC-84.)

## A.9 Conformance & module mapping

The contract maps to `src/shard_wiki/adapters/` (the bottom waist: `AdapterContract`,
`CapabilityProfile`, attachment-mode binding, the conformance suite) consuming `model/`
(page model + capability value types) and `provenance/` (blueprint §11). Each concrete adapter
ships its declared profile + a conformance pass.

*Decided:* A.1–A.8 (versioned capability contract, verified conformance, binding taxonomy,
page model, history portability, translation, addressing, gated computational content).
*Deferred:* per-backend adapter specs (one per backend, later). *Open:* blueprint §12 O-items
(addressing O-6, axis interactions O-5, span-authz O-10).

## 5. Integration Boundaries

- Authentication delegated to external identity provider (reference:
  net-kingdom + user-engine). See `demand/260608-netkingdom-integration-requirements.md`.
- No credential or secret storage in shard-wiki core.

## 6. Current Implementation

Package scaffold only (`__version__`, smoke tests). Domain model not yet coded.

## 7. Use Cases

`spec/UseCaseCatalog.md` — 84 use cases (UC-01–UC-84) from c2/yawex origins,
the wiki-engine + modern-tool + computational research, and the syntheses.

## 8. Next Specification Work

The design layer is complete: `SHARD-WP-0001` (→ `FederationRequirements.md`),
`SHARD-WP-0002` (→ `FederationArchitecture.md` + §A above), and the hardened
`CoreArchitectureBlueprint.md`. The next workplan is the **implementation** of the
domain model + adapter contract (starting from §A and blueprint §11's module layout),
likely with a first spike on the keystone (the event-sourced decision log + derived fold).