# Clay-Borg Architecture Blueprint

Reference architecture for the Clay-Borg framework. This document describes
the stable structural decisions: layers, component planes, capability ports,
data flows, and repository layout. For motivation and product intent see
[`../INTENT.md`](../INTENT.md); for the full originating exploration see
[`../history/260730-InitialExploration.md`](../history/260730-InitialExploration.md).
For the boundary between what the rules can see and everything else a
player experiences — and which repository each belongs to as the simulator
grows — see [`Ornamentation.md`](Ornamentation.md).

Status: **draft** — this blueprint is normative for new work but still
malleable (Clay). Changes go through a decision record in `decisions/`.

---

## 1. Layered architecture

```mermaid
flowchart TB
    TR["TargetRevenue Control Plane
    phases • workload • revenue • licensing • trust"]

    AF["Agentic Development Forge
    specifications • work packets • generators
    tests • scenarios • benchmarks • evidence"]

    GP["Game Packages
    GROUND • fixture games • future products"]

    TT["Tabletop Framework
    cards • decks • tokens • zones • hands
    seats • hidden information • manipulation"]

    GR["Game Runtime
    commands • validation • rules • events
    phases • simultaneous actions • replay"]

    WS["World and Simulation
    entities • components • transforms • time
    scheduling • spatial queries • snapshots"]

    PORTS["Canonical Capability Ports
    render • physics • network • assets
    UI • audio • persistence • scripting"]

    LIBS["Assimilated Libraries
    wgpu • Rapier • Bevy ECS • Wasmtime
    Quinn • egui • Serde • tracing"]

    PLATFORM["Platform Substrate
    native • browser/WASM • server • CI"]

    TR --> AF
    AF --> GP
    GP --> TT
    TT --> GR
    GR --> WS
    WS --> PORTS
    PORTS --> LIBS
    LIBS --> PLATFORM

    AF -.tests and measures.-> GR
    AF -.tests and measures.-> WS
    AF -.tests and measures.-> PORTS
    TR -.governs releases.-> GP
    TR -.governs releases.-> PORTS
```

### The four state kinds

Every subsystem must respect the separation between:

| State kind | Definition | Owner |
|---|---|---|
| **Authoritative semantic state** | What is legally happening in the game | Game runtime |
| **World state** | Where representations currently are | World layer |
| **Physical state** | How objects are moving | Physics port |
| **Presentation state** | What a particular player is allowed to see | Projection layer |

A game must remain playable in a headless process with no rendering and no
rigid-body simulation. The 3D tabletop is a projection and interaction
surface, never the definition of the game.

---

## 2. Clay Canon

The stable conceptual foundation shared by engines, games, tools, and agents.

| Component | Responsibility |
|---|---|
| Capability model | Names and describes each engine capability and its implementations |
| Canonical identifiers | Stable IDs for entities, players, assets, games, commands, events, sessions, packages |
| Schema system | Machine-readable definitions for game packages, assets, scenarios, engine configuration |
| Contract system | Interfaces and invariants every implementation must satisfy |
| Versioning model | Compatibility rules for APIs, schemas, save games, event logs |
| Capability registry | What exists, where it lives, maturity, dependencies, evidence, release phase |
| Assimilation manifests | Why a library was adopted, what boundary contains it, how it can be replaced |

### Assimilation manifest (required per external dependency)

```toml
capability = "physics.rigid-body.3d"
implementation = "rapier3d"
boundary_crate = "cb-physics-rapier"
canonical_interface = "cb-physics-api"

determinism = "authoritative-server"
replaceability = "high"
exposed_upstream_types = false

required_tests = [
  "physics-conformance",
  "snapshot-restore",
  "card-stack-stability",
  "drag-release-behavior",
]

required_benchmarks = [
  "1000-resting-cards",
  "deck-shuffle-and-deal",
  "multi-object-picking",
]
```

**Hard rule: no external library type leaks across a canonical interface.**
A card must not contain a `RapierRigidBodyHandle`, a `wgpu::Texture`, or an
engine-specific entity id.

---

## 3. Runtime substrate

The lowest layer Clay-Borg owns itself:

- Platform abstraction, application lifecycle
- Time and fixed simulation ticks
- Task scheduling and job execution
- Memory and resource ownership conventions
- Deterministic random-number streams
- Configuration and feature flags
- Diagnostics and structured tracing (`tracing`)
- Capability discovery
- Error taxonomy
- Shutdown, recovery, headless execution

### Port/implementation pattern

Every important capability ships a **null**, a **reference**, and (when
financed) an **optimized** implementation:

```text
cb-time-api
├── cb-time-realtime
└── cb-time-controlled

cb-render-api
├── cb-render-null
└── cb-render-wgpu

cb-network-api
├── cb-network-loopback
└── cb-network-quic

cb-physics-api
├── cb-physics-null
├── cb-physics-reference
└── cb-physics-rapier
```

Null and reference implementations keep tests fast, expose semantic
assumptions, and let agents work without a GPU or a multiplayer environment.

---

## 4. Simulation kernel

Small and largely independent of game-specific concepts.

### Entity and component model

- **ECS** (`bevy_ecs`, assimilated standalone — not full Bevy) for world
  composition, spatial representation, runtime scheduling.
- **Explicit typed aggregates** for game rules and authoritative state.
  Canonical game state is never reduced to arbitrary ECS components.

### Mutation pipeline

Every meaningful state change follows:

```text
Intent
  → Command
  → Validation
  → Domain Events
  → State Reducer
  → New Authoritative State
  → World/Presentation Projection
```

This yields replay, undo/branching, multiplayer sync, bot/agent access,
auditing, save-game migration, rule debugging, and scenario testing.

### Snapshots and event logs

- Periodic full snapshots; append-only event streams
- Stable event serialization (Serde behind versioned Clay-Borg schemas)
- State hashes, replay seeds, branching from earlier state
- Snapshot migration; expected-vs-actual state comparison
- **Every failed test produces a replay bundle an agent can execute locally.**

---

## 5. Physics subsystem

Physics is a **service of the world, not a source of game truth**.
Rapier is the optimized implementation; the server owns authoritative
physical outcomes while clients interpolate and predict interaction
feedback. Do not depend on independently simulated client physics remaining
identical across platforms.

Tabletop physics scope (initial, deliberately narrow): pick up / move /
flip / place a card, stack and unstack, move relation markers, snap tokens
to tracks, animate reveal and resolution, prevent accidental scattering.
Dice, complex joints, bags, arbitrary models, and unrestricted throwing come
later.

---

## 6. World-building layer

Binds semantic objects to spatial representations.

| Concept | Meaning |
|---|---|
| World | An independently simulated environment |
| Scene | A loadable arrangement of objects |
| Object | A spatially represented entity |
| Prototype | Reusable object definition |
| Instance | Runtime occurrence of a prototype |
| Transform | Position, orientation, scale |
| Zone | A spatial area with semantic meaning |
| Surface | Table, board, tray, or similar placement area |
| Seat | A participant position and viewpoint |
| View | Player-specific projection of world state |
| Binding | Connection between domain state and world objects |

The world system supports multiple simultaneous projections: authoritative
server world, player-visible worlds, spectator, debug, replay, and
agent-observation worlds. This is what makes hidden hands and simultaneous
decisions tractable.

---

## 7. Tabletop domain framework

Canonical tabletop object set (no game reinvents these):

```text
Table  Board  Card  Deck  Stack  Token  Counter  Marker  Die  Bag
Zone  Hand  Seat  PlayerPointer  Note  Rulebook  ScoreTrack
SequenceTrack  Timer
```

Each object carries: physical representation, semantic identity, ownership,
visibility policy, interaction permissions, allowed operations, snap
behavior, serialization, behavior hooks, presentation variants.

### Game-operation modes

| Mode | Rule |
|---|---|
| **Sandbox** | Players manipulate objects freely; physics is primary, rules are social |
| **Governed** | Only legal commands alter authoritative state; objects merely visualize |
| **Hybrid** | Physical gestures *propose* commands; zones, ownership, and rules decide acceptance |

GROUND uses **hybrid mode**: dragging a card toward another player only
becomes an attack or support action when the rules engine validates target,
relationship capacity, timing, and card availability.

---

## 8. Game runtime and packages

A game package describes five things separately:

1. **Content** — cards, tokens, text, symbols, assets
2. **Setup** — session initialization
3. **Rules** — legal commands and their effects
4. **Flow** — phases, simultaneous windows, end conditions
5. **Presentation bindings** — how semantic state appears on the table

```text
games/ground/
├── GAME.toml
├── INTENT.md
├── rules/          # ground.wit, phases.yaml, actions.yaml, resolution.yaml
├── content/        # cards.yaml, tokens.yaml, symbols.yaml
├── scenes/         # table.scene.yaml, tutorial.scene.yaml
├── assets/
├── scenarios/
├── bots/
├── tests/
└── migrations/
```

### Extension boundary

Early GROUND rules live in native Rust crates. The stable extension boundary
is later expressed through **WebAssembly Interface Types** loaded via
**Wasmtime**. A game component receives explicit capabilities from the host
(read public state, propose commands, spawn canonical objects) — never
direct filesystem, network, clock, or GPU access.

### Simultaneous action primitive

```text
Open decision window
→ privately choose action and target
→ commit
→ wait for all players or timeout
→ reveal
→ order or group interactions
→ resolve
→ emit consequences
```

Networked play uses commit/reveal semantics so early submissions cannot be
inspected and exploited. The interaction-group resolver (mutual attacks,
support opposing an attack, capacity conflicts, simultaneous end conditions)
is expected to become one of the first genuinely reusable Clay-Borg
capabilities.

---

---

**Continued in [ArchitectureRuntime.md](ArchitectureRuntime.md)** — §9
rendering/input/creation tools, §10 networking and sessions, §11 the
agentic inner loop, §12 TargetRevenue integration, §13 repository
structure, §14 milestones, §15 governing design decisions.

*(Split 2026-07-31: this file was 543 lines against the loop's ~400-line
whole-file loadability rule. The rule had been stated since v0.2 and
nothing measured it until `tools/loop-lint.py` — see
`history/260731-inner-loop-rule-audit.md`.)*