Wave 2 prep: LedgerEvent.ref, demo bridge protocol, artifact stubs, sendText in ChatActionsContext

components/artifacts/demo-card.tsx

@@ -0,0 +1,10 @@
+import type { ArtifactPartProps } from "@/src/core/contracts";
+
+/**
+ * Demo artifact card (W6): sandboxed iframe rendering DemoResult.html with
+ * the auto-injected resize/error bridge (contracts.ts "Demo iframe bridge").
+ * While input-available: job activity card (poll /api/jobs).
+ */
+export function DemoCard(_props: ArtifactPartProps) {
+	return null;
+}

components/artifacts/index.ts

@@ -1,6 +1,9 @@
 import type { ComponentType } from "react";
 import type { ArtifactPartProps } from "@/src/core/contracts";
+import { DemoCard } from "@/components/artifacts/demo-card";
 import { JobCard } from "@/components/artifacts/job-card";
+import { PlanDivider } from "@/components/artifacts/plan-divider";
+import { VisualCard } from "@/components/artifacts/visual-card";
 
 /**
  * Artifact renderer registry — the extension point for tool-part UI.
@@ -16,5 +19,9 @@ import { JobCard } from "@/components/artifacts/job-card";
  */
 export const artifactRenderers: Record<string, ComponentType<ArtifactPartProps>> = {
 	research: JobCard,
-	// W6: "demo" → sandboxed iframe card, "visual" → svg card
+	// Phase divider where the plan lands (W5 fills in the component):
+	plan_init: PlanDivider,
+	// Artifacts (W6 fills in the components):
+	demo: DemoCard,
+	visual: VisualCard,
 };

components/artifacts/plan-divider.tsx

@@ -0,0 +1,9 @@
+import type { ArtifactPartProps } from "@/src/core/contracts";
+
+/**
+ * Phase divider rendered where plan_init lands in the transcript (W5).
+ * Probe → teach transition marker per vision §2 "Two phases".
+ */
+export function PlanDivider(_props: ArtifactPartProps) {
+	return null;
+}

components/artifacts/visual-card.tsx

@@ -0,0 +1,9 @@
+import type { ArtifactPartProps } from "@/src/core/contracts";
+
+/**
+ * Visual artifact card (W6): renders VisualResult.svg inline.
+ * While input-available: job activity card (poll /api/jobs).
+ */
+export function VisualCard(_props: ArtifactPartProps) {
+	return null;
+}

components/chat.tsx

@@ -37,6 +37,8 @@ const COLUMN = "mx-auto w-full max-w-3xl px-4";
 export const ChatActionsContext = createContext<{
 	chatId: string;
 	syncFromServer: () => Promise<void>;
+	/** Send a user message into the session (demo error-fix loop, W6). */
+	sendText: (text: string) => void;
 } | null>(null);
 
 /** useLayoutEffect that is silent during SSR (client components still render on the server in Next). */
@@ -143,7 +145,7 @@ export function Chat({
 	};
 
 	return (
-		<ChatActionsContext.Provider value={{ chatId, syncFromServer }}>
+		<ChatActionsContext.Provider value={{ chatId, syncFromServer, sendText: (t: string) => void sendMessage({ text: t }) }}>
 		<div className="flex h-dvh flex-col">
 			<header className="flex items-center gap-3 px-3 py-2">
 				<SidebarToggle />

src/core/contracts.ts

@@ -99,6 +99,9 @@ export interface LedgerEvent {
 	kind: LedgerEventKind;
 	chatId: string;
 	at: string;
+	/** Idempotency key: the quiz part's toolCallId or `taught:<treeNodeId>` —
+	 * re-emission of the same chat must never double-record an event. */
+	ref?: string;
 	/** The learner's quiz note — diagnostic gold (vision §1 calibration). */
 	note?: string;
 	/** The quiz question text, when nodeId is null (later attribution input). */
@@ -206,6 +209,24 @@ export interface VisualResult {
 	notes?: string;
 }
 
+// ─── Demo iframe bridge (W6) ────────────────────────────────────────────────
+// postMessage protocol between the sandboxed demo iframe and its parent card.
+// The bridge script is auto-injected into every demo HTML by the demo-card
+// renderer (never the model's job): ResizeObserver → DEMO_RESIZE with the
+// document height; window.onerror → DEMO_ERROR with the message.
+
+export interface DemoResizeMessage {
+	type: "demo-resize";
+	height: number;
+}
+
+export interface DemoErrorMessage {
+	type: "demo-error";
+	message: string;
+}
+
+export type DemoBridgeMessage = DemoResizeMessage | DemoErrorMessage;
+
 // ─── Artifact renderer registry (client extension point) ────────────────────
 
 /**