crisis/CrisisViz/HANDOFF.md

CrisisViz — Agent-to-Agent Handoff

Audience. This file is the engineering log for the next coding agent to pick up this project. It assumes Swift, SwiftUI, macOS 26, and the Crisis protocol context from ../README.md. For human-facing orientation see README.md next to this file.

Last updated: 2026-05-14.

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1. Current state — what's shipped

• All 10 chapters migrated to the serial-beat timeline pattern (pure state(at: t) -> WorldState, scrubbable −16× to +16×, beat-bound narration).
• Testbed green at the last clean run: 38/38 invariants pass, 0 source-audit errors, 36/36 MP4 clips written, 279 PNGs sane, 12/12 resize cases pass.
• origin/master at fb9bc9c — working tree was clean before this documentation/testing pass. After this pass: README.md/INSTALL.md/LICENSE/CrisisViz README&HANDOFF/package-dmg.sh/Python tests landed.
• Bundle pipeline works. ./bundle.sh produces a working CrisisViz.app. ./package-dmg.sh produces a working CrisisViz.dmg (ad-hoc signed; first-open Gatekeeper warning, right-click → Open).

If you can't run the testbed and confirm it's green, stop and fix that first before making curriculum changes.

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2. The pure-function timeline pattern (this is the architecture)

Every chapter is split into two files:

Sources/CrisisViz/Engine/ChXXTimeline.swift     pure model (state machine over t)
Sources/CrisisViz/Chapters/ChXX_Foo.swift       thin Canvas renderer (no logic)

The timeline file is the contract. It contains:

1. A typed BeatKind enum capturing the chapter's micro-events (e.g. introduce(name:), compose(by:), sealAccepted(at:), gossipFly(from:to:), linkBroken, …).
2. A WorldState struct holding the cumulative state at a moment in time (introduced cast set, accepted vertices per lane, in-flight envelopes, broken links, vault contents, …).
3. A flat [Beat] list. Each Beat has (id, kind, durationSeconds, narration). Narration is one sentence describing what that beat physically shows.
4. A state(at: Double) -> WorldState pure function. Replays every beat up to t produces the state. Pure ⇒ scrubbable + reverse-playable. No monotonic accumulators, no hidden @State.
5. A ChXXScenes enum with sceneStarts, sceneDurations, timelineT(sceneIndex, localTime), narrationAt(sceneIndex, localTime). The chapter's existing scene count stays — scenes become navigation labels on the unified timeline.

The renderer file is thin:

TimelineView(.animation) { timeline in
    Canvas { ctx, size in
        let t = ChXXScenes.timelineT(sceneIndex: sceneIndex, localTime: localTime)
        let world = ChXXTimeline.state(at: t)
        // draw the world from `world`. No per-scene switch.
    }
}

SceneEngine.durationOverrides gets per-scene durations matching the timeline's windows. ImmersiveView.liveNarration adds a case for the new chapter, reading from ChXXScenes.narrationAt.

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3. Pedagogy invariants the renderer MUST hold

These are not stylistic preferences — the testbed enforces them. Break one, the source audit fails.

• Strictly serial. Never two simultaneous events on screen. Every beat owns its time window exclusively.
• Cast appears via introduce(...) beats only. Lanes for not-yet-introduced cast are invisible. Their lane labels are also hidden.
• Lane = lifeline. A vertex belonging to player P sits exactly on $P$'s lane Y. No jitter, ever. Source audit forbids reintroducing hashJitterY.
• Composing and open-envelope share ONE fixed top-center slot (detailSlotRect, y ≈ 16..146 + ~30pt caption). They never co-occur on the timeline.
• In-flight envelopes draw on a courier track 36pt above the lane axis so they don't collide with the just-sealed accepted vertex on the sender's lane.
• Cast colors via dm.castColor(for:) — never palette[i]. Lane order via dm.castOrderedNodes() — never raw sim.nodes (would put Dave at lane 8 below 5 peers).
• Beat tag (small, faint, top-right) so PNG sweeps can be matched to a specific beat for debugging.
• Scene indicator CH X.Y (n/N) badge on the narration panel, visible even when collapsed.

When designing a new beat, picture all of these on screen at once (lane labels left margin, cast circles with ~50pt halos, detailSlotRect top band, courier track at lane Y − 36, accepted-vertex rows right of cast circles, GlassNarration bottom-left ~340pt × 250pt expanded, GlassControls bottom ~80pt). If the new beat lands on top of any of those, redesign before shipping.

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4. Hard-won rules from past sessions

These are the ones that bite repeatedly. Memorize them.

Rule	Why
Restart the live .app after Swift changes	The Dock icon launches CrisisViz.app, not the swift-run dev binary. Run ./bundle.sh --no-launch && open CrisisViz.app.
Testbed can't verify animation smoothness	Static PNG sweeps catch layout bugs; MP4 clips catch motion bugs; but the user-experience of scrub feel can only be evaluated live. Always restart and watch.
Narration ≡ canvas	When a scene's title is a narrative beat ("Aaron speaks. Ben listens."), hand-curate the visible-vertex set to match. Progressive reveal by sceneVertexCount alone will under-show or over-show and make the narration lie.
Arrows must be visible	Edges drawn as Path lines without arrowheads are not arrows. Use drawArrowEdge. Every narrated causal claim ("Ben copies Aaron") must be physically renderable from the data.
Layout is computed from the full dataset	Compute positions from sim.nodes[step=lastStep], reveal only a subset via sceneVertexCount. Positions never jump because layout input doesn't change.

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5. Test harness reference

swift run CrisisViz --testbed → ~/Desktop/CrisisViz_Testbed/. Five layers:

Layer	File	Catches
Narrative invariants	Testbed/NarrativeInvariants.swift	logical claims about staging, cast assignment, geometry, sim convergence
Source pattern audit	Testbed/SourceAudit.swift	regex-forbidden patterns (lane jitter, palette[i], hardcoded PIDs)
Per-scene MP4 clips	Testbed/SceneVideoCapture.swift	animation continuity (36 clips at 8s/30fps)
PNG time-scrubbing sweep	Testbed/SceneCapture.swift	frozen interpolators, all-black renders, label drift
Window resize + sanity	Testbed/SceneCapture.swift	clamping correctness, tiny renders, byte-identical frames

When adding a new chapter / scene / design rule, update the corresponding layer in the same commit:

• New chapter → add invariants in NarrativeInvariants.swift (expected visible vertex count, expected cast members, expected edges).
• New design rule → add a Rule to SourceAudit.rules with the legitimate definition site whitelisted in allowedFiles.
• New animation → confirm the scene's MP4 actually contains motion. Scrub it.

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6. Known open items

Surfaced from working memory at handoff. None blocking, all valuable:

1. DA-chapter polish (Ch07 / Ch08). Both are on the serial-timeline pattern but the shard / vault animations are still abstract relative to the cast-on-lane discipline elsewhere. Could be tightened so shards are physically carried by Aaron / Ben / Carl / Dave lanes.
2. Per-scene visible-vertex-count invariants. Currently 38 logical invariants; adding count assertions per scene would catch staging regressions before they ship.
3. LaneRenderKit extraction. Geometry helpers castLaneY, castPosition, castColor, drawIntroducedLanes, drawCastFigures are duplicated across cast-heavy chapters (Ch00, Ch01, Ch02, Ch09 — four adopters now, more than enough). Factor into a shared file.
4. Animation smoothness verification protocol. No testbed signal — only live-app eyeballing on Ch01 staging, Ch02 partition, Ch06 total-order convergence, Ch09 byzantine. Recurring blind spot; consider an MP4 difference-frame analyzer.
5. CrisisNode / gossip TCP integration tests. The real distributed runtime (src/crisis/node.py, src/crisis/gossip.py) has zero tests. Not blocking the visualizer (which uses SimulatedNode), but the deployable side is currently unverified.

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7. How to resume

cd /Users/oho/GitClone/ClaudeCodeProjects/crisis/CrisisViz

# 1. Compile + trust SourceKit
swift build

# 2. After source changes: rebuild the bundle
./bundle.sh --no-launch
open CrisisViz.app

# 3. Verify the testbed before committing curriculum changes
swift run CrisisViz --testbed
# read ~/Desktop/CrisisViz_Testbed/INVARIANTS.md, SOURCE_AUDIT.md,
# VIDEO_CLIPS.md, MANIFEST.md, SANITY.md — all must be green

# 4. For distribution
./package-dmg.sh
# produces CrisisViz.dmg, prints SHA-256

If something feels broken, check in this order: (1) is crisis_data.json present and non-empty? (2) does swift build succeed cleanly? (3) does the dev binary swift run CrisisViz produce a window? (4) does ./bundle.sh succeed and open CrisisViz.app show the same window with a Dock icon? (5) does the testbed run to completion?