diff --git a/CrisisViz/README.md b/CrisisViz/README.md
new file mode 100644
index 0000000..d8f5673
--- /dev/null
+++ b/CrisisViz/README.md
@@ -0,0 +1,136 @@
+# CrisisViz
+
+A native macOS 26 / SwiftUI keynote-style visualizer for the Crisis consensus protocol. Ten chapters, roughly eighteen minutes of curated playback at $1\times$, scrubbable forward and backward at any signed rate from $-16\times$ to $+16\times$.
+
+CrisisViz consumes a recorded simulation from `crisis_data.json` and replays it with narration bound to specific narrative beats — the playhead is the master of time.
+
+---
+
+## The serial-timeline pattern
+
+Every chapter is a **pure function of normalized time**. Given a chapter with an ordered list of beats $b_0, b_1, \ldots, b_{n-1}$ each with duration $d_i$, the world state at time $t \in [0, T]$ (where $T = \sum d_i$) is:
+
+$$\text{state}(t) = \mathop{\textrm{fold}}_{i\,:\,\sum_{j<i} d_j \le t} (b_i, \text{state}_{\text{init}})$$
+
+That is: replay every beat whose start lies before $t$, accumulating into a `WorldState` struct. Pure ⇒ scrubbable ⇒ reverse-playable. No monotonic accumulators, no animation state hidden in `@State`.
+
+```mermaid
+flowchart LR
+    Engine["<b>SceneEngine</b><br/>signed speed · pause · scrubber"]
+    Engine -->|sceneIndex, localTime| Timeline
+    Timeline["<b>ChXXTimeline</b><br/>state(at:t) → WorldState<br/>narrationAt(scene, t)"]
+    Timeline -->|WorldState| View
+    View["<b>ChXX_Foo (Canvas)</b><br/>thin renderer"]
+    View -->|draw| Canvas["macOS Canvas + GraphicsContext"]
+    Timeline -->|narration text| Glass["<b>GlassNarration</b><br/>beat-bound overlay"]
+
+    classDef engine fill:#cfe2f3,stroke:#2c5f8f,color:#062b4d
+    classDef pure fill:#d9ead3,stroke:#38761d,color:#0b3d0b
+    classDef view fill:#ead1dc,stroke:#741b47,color:#3d0a26
+    classDef ui fill:#fff2cc,stroke:#bf9000,color:#3d2e00
+    class Engine engine
+    class Timeline pure
+    class View,Canvas view
+    class Glass ui
+```
+
+### The chapters
+
+| # | File pair | Beats | $T$ at $1\times$ | Concept |
+|---|---|--:|--:|---|
+| 0 | `Ch01_Problem.swift` + `Ch00Timeline.swift` | 12 | ~43 s | Four friends, one ledger, no boss |
+| 1 | `Ch02_Graph.swift` + `Ch01Timeline.swift` | ~75 | ~326 s | Asynchronous gossip & Lamport DAG |
+| 2 | `Ch03_Partition.swift` + `Ch02Timeline.swift` | 27 | ~115 s | Network partition splits the graph |
+| 3 | `Ch04_Rounds.swift` + `Ch03Timeline.swift` | 17 | ~72 s | Witness weight → round boundary |
+| 4 | `Ch05_Voting.swift` + `Ch04Timeline.swift` | 15 | ~63 s | Virtual voting via strongly-seeing paths |
+| 5 | `Ch06_Leader.swift` + `Ch05Timeline.swift` | 10 | ~48 s | Leader election |
+| 6 | `Ch07_Order.swift` + `Ch06Timeline.swift` | 11 | ~52 s | Total order — convergence guarantee |
+| 7 | `Ch08_DA_Problem.swift` + `Ch07Timeline.swift` | 14 | ~69 s | Data availability: gossip ≠ storage |
+| 8 | `Ch09_DA_Design.swift` + `Ch08Timeline.swift` | 19 | ~85 s | Erasure shards + Merkle proofs |
+| 9 | `Ch10_Byzantine.swift` + `Ch09Timeline.swift` | 18 | ~80 s | $f < n/3$ fork detection |
+
+Naming gotcha: **chapter renderers are 1-indexed** (`Ch01..Ch10`), **timelines are 0-indexed** (`Ch00Timeline..Ch09Timeline`). They pair off-by-one. The renderer file's number matches the user-facing chapter label.
+
+---
+
+## Build · run · test · distribute
+
+```sh
+swift build                        # dev binary
+swift run CrisisViz                # launch dev binary (no Dock icon)
+./bundle.sh                        # build + assemble CrisisViz.app + open
+./bundle.sh --no-launch            # build only
+swift run CrisisViz --testbed      # PNG + MP4 + invariants harness
+./package-dmg.sh                   # build CrisisViz.dmg for distribution
+```
+
+For first-time setup and prerequisites see [`../INSTALL.md`](../INSTALL.md).
+
+---
+
+## Testbed outputs
+
+`swift run CrisisViz --testbed` writes everything to `~/Desktop/CrisisViz_Testbed/`:
+
+| File | What it verifies |
+|---|---|
+| `INVARIANTS.md` | 38 logical curriculum assertions (cast colors, lane Y positions, scene staging) |
+| `SOURCE_AUDIT.md` | Regex audit of all `.swift` files — forbidden patterns like `hashJitterY`, `palette[i]`, hardcoded colors |
+| `MANIFEST.md` | PNG sweep across all scenes × time offsets $\{0, 2, 4, 6, 8\}\,\text{s}$ |
+| `VIDEO_CLIPS.md` | 36 MP4 clips at $8\,\text{s} / 30\,\text{fps}$, one per scene |
+| `SANITY.md` | File-size + freeze-frame heuristic checks (catches dead canvases) |
+
+All five must be green before shipping curriculum changes. The testbed verifies **layout and logical claims**; it cannot evaluate animation smoothness — that requires running the live app and watching.
+
+---
+
+## Controls
+
+| Input | Action |
+|---|---|
+| **← / →** | previous / next scene (across all chapters) |
+| **Space** | play / pause |
+| Bottom slider | signed speed, $-16\times$ to $+16\times$ |
+| Chapter scrubber | jump to any chapter |
+| Click a vertex | open the vertex inspector overlay |
+
+---
+
+## Cast convention
+
+The visualizer adopts a fixed cast of named players over a subset of the simulation's process IDs:
+
+| Lane | Name | Role |
+|---|---|---|
+| 0 | **Aaron** | leader-eligible honest |
+| 1 | **Ben** | honest |
+| 2 | **Carl** | honest |
+| 3 | **Dave** | the Byzantine in Chapter 9 |
+| 4+ | anonymous peers | the rest of the simulated nodes |
+
+Hard rules:
+
+- **Lane = lifeline.** Vertices sit exactly on their player's lane Y. No jitter, ever. Source audit forbids reintroducing `hashJitterY`.
+- **Strictly serial.** Never two simultaneous events on screen at the same time.
+- **Introduce before show.** A cast member's lane is invisible until their `introduce(...)` beat fires.
+- **One detail slot.** The top-center "composing / open-envelope" panel is a single fixed rectangle; only one envelope occupies it at a time.
+
+---
+
+## Architecture pointers
+
+| Concern | File |
+|---|---|
+| `@main`, activation policy, window clamping | `Sources/CrisisViz/App/CrisisApp.swift` |
+| Playback controller (signed speed, scrubber) | `Sources/CrisisViz/Engine/SceneEngine.swift` |
+| Pure per-chapter timelines | `Sources/CrisisViz/Engine/ChNNTimeline.swift` |
+| Cast → color → lane mapping | `Sources/CrisisViz/Engine/DataManager.swift` |
+| Chapter metadata, scene routing | `Sources/CrisisViz/Model/ChapterDefinitions.swift` |
+| Cast definitions | `Sources/CrisisViz/Model/Cast.swift` |
+| Main canvas + inter-chapter morph | `Sources/CrisisViz/Views/ImmersiveView.swift` |
+| DAG layout (lane = lifeline) | `Sources/CrisisViz/Canvas/DAGLayoutEngine.swift` |
+| Bottom controls bar | `Sources/CrisisViz/Glass/GlassControls.swift` |
+| Beat-bound narration overlay | `Sources/CrisisViz/Glass/GlassNarration.swift` |
+| Testbed entry points | `Sources/CrisisViz/Testbed/` |
+
+For the engineering log oriented at the next coding agent, see [`HANDOFF.md`](HANDOFF.md).