diff --git a/components/diagnostics-view.jsx b/components/diagnostics-view.jsx
index 60a5d05..07433ea 100644
--- a/components/diagnostics-view.jsx
+++ b/components/diagnostics-view.jsx
@@ -1,3 +1,5 @@
+import React from "react";
+
 const ValidationIndicator = ({ status }) => {
   const styles = {
     valid: "text-green-600",
@@ -27,23 +29,53 @@ const validationIcons = {
 export default function DiagnosticsView({ result }) {
   if (!result) return null;
 
+  const diagnostics = result.diagnostics || result;
+
   const metrics = [
-    { label: "Model", value: result.modelName || "?" },
+    { label: "Model", value: diagnostics.modelName || result.modelName || "?" },
     { label: "Provider", value: "Ollama" },
-    { label: "Prompt version", value: result.promptVersion || "?" },
+    {
+      label: "Prompt version",
+      value: diagnostics.promptVersion || result.promptVersion || "?",
+    },
     {
       label: "Duration",
       value:
-        result.responseDurationMs != null
-          ? `${result.responseDurationMs}ms`
+        diagnostics.responseDurationMs != null
+          ? `${diagnostics.responseDurationMs}ms`
           : "?",
     },
     {
       label: "Validation",
       value: (
-        <ValidationIndicator status={result.validationStatus || "invalid"} />
+        <ValidationIndicator
+          status={diagnostics.validationStatus || result.validationStatus || "invalid"}
+        />
       ),
     },
+    {
+      label: "Node count",
+      value: diagnostics.nodeCount != null ? diagnostics.nodeCount : "?",
+    },
+    {
+      label: "Edge count",
+      value: diagnostics.edgeCount != null ? diagnostics.edgeCount : "?",
+    },
+    {
+      label: "Graph references",
+      value:
+        diagnostics.graphReferenceValidation == null
+          ? "?"
+          : diagnostics.graphReferenceValidation.valid
+            ? `${validationIcons.valid} valid`
+            : `${validationIcons.invalid} invalid`,
+    },
+  ];
+
+  const errors = [
+    ...(result.errors || []),
+    ...(result.validationErrors || []),
+    ...(result.analysisErrors || []),
   ];
 
   return (
@@ -72,14 +104,14 @@ export default function DiagnosticsView({ result }) {
       )}
 
       {/* Errors if present */}
-      {result.errors && result.errors.length > 0 && (
+      {errors.length > 0 && (
         <details className="mt-3">
           <summary className="cursor-pointer text-xs text-red-500 underline hover:text-red-700">
-            Validation errors ({result.errors.length})
+            Validation errors ({errors.length})
           </summary>
           <ul className="mt-1 space-y-0.5 text-xs text-red-600">
-            {result.errors.map((err, i) => (
-              <li key={i}>{err}</li>
+            {errors.map((err, i) => (
+              <li key={i}>{typeof err === "string" ? err : err?.message || JSON.stringify(err)}</li>
             ))}
           </ul>
         </details>
diff --git a/components/scenario-form.jsx b/components/scenario-form.jsx
index fb2e7d8..e71bc28 100644
--- a/components/scenario-form.jsx
+++ b/components/scenario-form.jsx
@@ -1,14 +1,59 @@
 "use client";
 
+import React from "react";
 import { useState, useRef } from "react";
-import ReconstructionView from "@/components/reconstruction-view";
 import DiagnosticsView from "@/components/diagnostics-view";
+import SituationGraphView from "@/components/situation-graph-view";
 
 const MAX_LENGTH = 10000;
 
+export async function submitScenarioForStartCase(fetchImpl, scenario) {
+  return fetchImpl("/api/cases/start", {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({ scenario }),
+  });
+}
+
+export function ScenarioResultPanels({ status, result }) {
+  if (!result) return null;
+
+  const hasGraph = Boolean(result.situationGraph);
+  const hasQuestion = Boolean(result.selectedQuestion?.question);
+  const hasDiagnostics = Boolean(result.diagnostics);
+
+  return (
+    <>
+      {status === "error" && (
+        <div className="space-y-3">
+          {result.error && (
+            <div className="rounded-lg border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700 whitespace-pre-wrap">
+              Error: {result.error}
+            </div>
+          )}
+          {!hasGraph && !hasQuestion && (
+            <div className="rounded-lg border border-yellow-300 bg-yellow-50 px-4 py-2 text-sm text-yellow-800">
+              Validation failed — no structured graph output was produced.
+            </div>
+          )}
+        </div>
+      )}
+
+      {(status === "success" || hasGraph || hasQuestion) && (
+        <SituationGraphView
+          situationGraph={result.situationGraph}
+          selectedQuestion={result.selectedQuestion}
+        />
+      )}
+
+      {hasDiagnostics && <DiagnosticsView result={result} />}
+    </>
+  );
+}
+
 export default function ScenarioForm() {
   const [scenario, setScenario] = useState("");
-  const [status, setStatus] = useState("idle"); // idle | loading | error | success | partial
+  const [status, setStatus] = useState("idle"); // idle | loading | error | success
   const [result, setResult] = useState(null);
   const textareaRef = useRef(null);
 
@@ -18,19 +63,11 @@ export default function ScenarioForm() {
     setResult(null);
 
     try {
-      const res = await fetch("/api/analyse", {
-        method: "POST",
-        headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ scenario }),
-      });
+      const res = await submitScenarioForStartCase(fetch, scenario);
 
       const data = await res.json();
 
-      if (res.ok && data.validationStatus === "valid") {
-        setStatus("success");
-        setResult(data);
-      } else if (data.success) {
-        // Success in analysis but validation may be partial
+      if (res.ok && data.success) {
         setStatus("success");
         setResult(data);
       } else {
@@ -43,14 +80,6 @@ export default function ScenarioForm() {
     }
   };
 
-  // Determine if we have meaningful content to display
-  const hasClassification = result?.inputClassification;
-  const hasReconstruction = result?.reconstruction;
-  const hasNextQuestion = result?.nextQuestion;
-  const hasEvidence = result?.evidence && result.evidence.length > 0;
-  const hasMeaningfulContent =
-    hasClassification || hasReconstruction || hasNextQuestion || hasEvidence;
-
   return (
     <div className="space-y-6">
       <form onSubmit={handleSubmit} className="space-y-4">
@@ -76,38 +105,7 @@ export default function ScenarioForm() {
         </div>
       </form>
 
-      {/* Error state */}
-      {status === "error" && (
-        <div className="space-y-3">
-          {result?.error && (
-            <div className="rounded-lg border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700 whitespace-pre-wrap">
-              Error: {result.error}
-            </div>
-          )}
-          {/* Show partial content even on validation failure */}
-          {(hasClassification || hasReconstruction) && (
-            <div className="rounded-lg border border-yellow-300 bg-yellow-50 px-4 py-2 text-sm text-yellow-800">
-              ⚠ Partial result — some fields failed validation. Showing what was
-              accepted.
-            </div>
-          )}
-          {hasReconstruction && (
-            <ReconstructionView reconstruction={result} partial />
-          )}
-        </div>
-      )}
-
-      {/* Success state */}
-      {status === "success" && hasMeaningfulContent && (
-        <div className="space-y-4">
-          <ReconstructionView reconstruction={result} />
-        </div>
-      )}
-
-      {/* Always show diagnostics when we have any result */}
-      {(hasClassification || hasReconstruction || hasNextQuestion) && (
-        <DiagnosticsView result={result} />
-      )}
+      <ScenarioResultPanels status={status} result={result} />
 
       {status === "loading" && (
         <div className="py-12 text-center text-sm text-gray-400">
@@ -123,13 +121,6 @@ export default function ScenarioForm() {
           </p>
         </div>
       )}
-
-      {/* Invalid result with no partial data */}
-      {status === "error" && !result?.error && !hasMeaningfulContent && (
-        <div className="rounded-lg border border-yellow-300 bg-yellow-50 px-4 py-2 text-sm text-yellow-800">
-          Validation failed — no structured output was produced.
-        </div>
-      )}
     </div>
   );
 }
diff --git a/components/situation-graph-view.jsx b/components/situation-graph-view.jsx
new file mode 100644
index 0000000..81bd33a
--- /dev/null
+++ b/components/situation-graph-view.jsx
@@ -0,0 +1,121 @@
+"use client";
+
+import React from "react";
+
+function NodeBadge({ children, tone = "gray" }) {
+  const tones = {
+    gray: "border-gray-200 bg-gray-50 text-gray-700",
+    blue: "border-blue-200 bg-blue-50 text-blue-700",
+    green: "border-green-200 bg-green-50 text-green-700",
+    yellow: "border-yellow-200 bg-yellow-50 text-yellow-700",
+  };
+
+  return (
+    <span className={`rounded-full border px-2 py-0.5 text-xs ${tones[tone] || tones.gray}`}>
+      {children}
+    </span>
+  );
+}
+
+function NodeGroup({ title, nodes }) {
+  if (!nodes?.length) return null;
+
+  return (
+    <section className="rounded-lg border border-gray-200 bg-white p-4">
+      <h3 className="mb-3 text-sm font-semibold text-gray-700">
+        {title} ({nodes.length})
+      </h3>
+      <ul className="space-y-3">
+        {nodes.map((node) => (
+          <li key={node.id} className="rounded border border-gray-100 bg-gray-50 p-3 text-sm">
+            <div className="flex flex-wrap items-center gap-2">
+              <span className="font-medium text-gray-900">{node.label}</span>
+              <NodeBadge tone="blue">{node.status}</NodeBadge>
+              <NodeBadge tone="green">{node.confidence}</NodeBadge>
+              {node.value != null && (
+                <NodeBadge tone="yellow">
+                  {node.value}
+                  {node.unit ? ` ${node.unit}` : ""}
+                </NodeBadge>
+              )}
+            </div>
+            {node.description && node.description !== node.label && (
+              <p className="mt-1 text-gray-600">{node.description}</p>
+            )}
+          </li>
+        ))}
+      </ul>
+    </section>
+  );
+}
+
+export default function SituationGraphView({
+  situationGraph,
+  selectedQuestion,
+}) {
+  if (!situationGraph) return null;
+
+  const activeUnknown = situationGraph.activeUnknownNodeId
+    ? situationGraph.nodes.find((node) => node.id === situationGraph.activeUnknownNodeId)
+    : null;
+
+  const nodesByKind = situationGraph.nodes.reduce((acc, node) => {
+    if (!acc[node.kind]) acc[node.kind] = [];
+    acc[node.kind].push(node);
+    return acc;
+  }, {});
+
+  return (
+    <div className="space-y-4">
+      {selectedQuestion?.question && (
+        <section className="rounded-lg border-2 border-green-300 bg-green-50 p-5">
+          <h2 className="mb-2 text-base font-bold text-green-800">Selected Question</h2>
+          <p className="text-base font-medium text-gray-900">{selectedQuestion.question}</p>
+        </section>
+      )}
+
+      <section className="rounded-lg border border-gray-200 bg-white p-4">
+        <h2 className="mb-2 text-base font-semibold text-gray-900">Situation Graph</h2>
+        <dl className="space-y-2 text-sm">
+          <div>
+            <dt className="text-gray-500">Central statement</dt>
+            <dd className="font-medium text-gray-900">{situationGraph.centralStatement}</dd>
+          </div>
+          {situationGraph.currentSummary && (
+            <div>
+              <dt className="text-gray-500">Current summary</dt>
+              <dd className="text-gray-800">{situationGraph.currentSummary}</dd>
+            </div>
+          )}
+          {activeUnknown && (
+            <div>
+              <dt className="text-gray-500">Active unknown</dt>
+              <dd className="text-gray-900">{activeUnknown.label}</dd>
+            </div>
+          )}
+          <div>
+            <dt className="text-gray-500">Edge count</dt>
+            <dd className="text-gray-900">{situationGraph.edges.length}</dd>
+          </div>
+        </dl>
+      </section>
+
+      {Object.entries(nodesByKind).map(([kind, nodes]) => (
+        <NodeGroup
+          key={kind}
+          title={kind.replace(/_/g, " ")}
+          nodes={nodes}
+        />
+      ))}
+
+      <details className="rounded-lg border border-gray-200 bg-gray-50 p-4">
+        <summary className="cursor-pointer text-sm font-medium text-gray-700 underline">
+          Raw graph JSON
+        </summary>
+        <pre className="mt-3 overflow-auto rounded bg-gray-900 p-3 text-xs text-green-400">
+          {JSON.stringify(situationGraph, null, 2)}
+        </pre>
+      </details>
+    </div>
+  );
+}
\ No newline at end of file
diff --git a/docs/v0.4-route-status.md b/docs/v0.4-route-status.md
index ff52c37..f423afa 100644
--- a/docs/v0.4-route-status.md
+++ b/docs/v0.4-route-status.md
@@ -5,10 +5,9 @@
   - Covered by `tests/app/api/cases-start-route.test.js`.
 
 - `app/api/start-case/route.js`
-  - Untracked earlier experiment / duplicate start route.
-  - Not referenced by the current UI.
-  - Still mentioned in untracked handoff docs.
-  - Leave untracked for now; recommend deletion once route migration is explicitly confirmed.
+  - Earlier experiment / duplicate start route.
+  - No repository UI/test references were found.
+  - Deleted from the working tree during UI connection cleanup.
 
 - `app/api/update-case/route.js`
   - Untracked future `updateCase` work.
@@ -16,5 +15,6 @@
   - Leave untracked for the current milestone.
 
 - Current UI status
-  - `components/scenario-form.jsx` still calls `/api/analyse`.
-  - No active UI path currently calls `/api/cases/start`, `/api/start-case`, or `/api/update-case`.
+  - `components/scenario-form.jsx` now calls `/api/cases/start` for the main experimental flow.
+  - `/api/analyse` remains available for compatibility.
+  - No active UI path currently calls `/api/update-case`.
diff --git a/tests/smoke.test.js b/tests/smoke.test.js
index f5cef5e..a15f642 100644
--- a/tests/smoke.test.js
+++ b/tests/smoke.test.js
@@ -1,55 +1,70 @@
 import { test, expect } from "@playwright/test";
 
-test("v0.3 UI smoke test with live model response", async ({ page }) => {
-  await page.goto("http://localhost:3000");
+const BASE_URL = process.env.PLAYWRIGHT_BASE_URL || "http://localhost:3000";
+
+test.setTimeout(300000);
+
+test("graph-backed start flow smoke test", async ({ page }) => {
+  await page.goto(BASE_URL);
 
   // Page should load without error
   await expect(page.getByText(/Confidence Engine/i)).toBeVisible();
 
   // Type the scenario
   const textarea = page.locator("textarea[placeholder*='Describe']");
-  await textarea.fill("Complaints increased by 35% while production increased by 40%.");
+  await textarea.fill(
+    "Complaints increased by 35% while production increased by 40%.",
+  );
+  await expect(textarea).toHaveValue(
+    "Complaints increased by 35% while production increased by 40%.",
+  );
 
   // Button should be enabled
   await expect(page.getByRole("button", { name: /Analyse/i })).toBeEnabled();
 
-  // Click Analyse and wait for diagnostics panel
+  // Click Analyse and wait for graph-backed result
   await page.getByRole("button", { name: /Analyse/i }).click();
-  
-  // Wait for result section (ReconstructionView rendered)
-  await expect(page.getByRole("heading", { name: /Next Question/i })).toBeVisible({ timeout: 180000 });
 
-  // Take screenshot of result page
-  await page.screenshot({ path: "tests-results/smoke-v0.3.png", fullPage: true });
+  await expect(
+    page.getByRole("heading", { name: /Selected Question/i }),
+  ).toBeVisible({ timeout: 180000 });
+  await expect(
+    page.getByRole("heading", { name: /Situation Graph/i }),
+  ).toBeVisible({ timeout: 180000 });
+  await expect(page.getByText(/Central statement/i)).toBeVisible();
+  await expect(page.getByText(/Active unknown/i)).toBeVisible();
+  await expect(page.getByText(/Error:/i)).toHaveCount(0);
 
-  // Verify diagnostics panel exists and contains relevant info
-  const diagPanel = page.locator('details summary').first();
-  if (await diagPanel.isVisible()) {
-    console.log("Raw response viewer:", await diagPanel.innerText().catch(() => "not visible"));
-  }
+  const rawJsonToggle = page.getByText(/Raw graph JSON/i);
+  await expect(rawJsonToggle).toBeVisible();
+  await rawJsonToggle.click();
+  await expect(page.getByText(/centralStatement/i)).toBeVisible();
 
   // Get full body text for verification
   const bodyText = await page.locator("body").innerText();
-  
+
   console.log("\n=== UI Smoke Test Results ===");
   console.log("Page title:", await page.title());
   console.log("Body content length:", bodyText.length);
-  
+
   // Check key content indicators
-  const hasNextQ = bodyText.includes("Next Question");
-  const hasComplaints = bodyText.includes("Complaint") || bodyText.includes("complaint");
-  const hasProduction = bodyText.includes("production") || bodyText.includes("Production");
-  const hasRateContext = bodyText.toLowerCase().includes("rate") || 
-                         bodyText.toLowerCase().includes("unit") ||
-                         bodyText.toLowerCase().includes("denominator") ||
-                         bodyText.toLowerCase().includes("per-unit");
-  
-  console.log("Has Next Question heading:", hasNextQ);
+  const hasSelectedQuestion = bodyText.includes("Selected Question");
+  const hasComplaints =
+    bodyText.includes("Complaint") || bodyText.includes("complaint");
+  const hasProduction =
+    bodyText.includes("production") || bodyText.includes("Production");
+  const hasRateContext =
+    bodyText.toLowerCase().includes("rate") ||
+    bodyText.toLowerCase().includes("unit") ||
+    bodyText.toLowerCase().includes("denominator") ||
+    bodyText.toLowerCase().includes("per-unit");
+
+  console.log("Has selected question heading:", hasSelectedQuestion);
   console.log("Has complaints reference:", hasComplaints);
   console.log("Has production reference:", hasProduction);
   console.log("Has rate context (rate/unit/denominator):", hasRateContext);
 
   // Basic structural checks
   expect(bodyText.length).toBeGreaterThan(200);
-  expect(hasNextQ).toBe(true);
-}, { timeout: 300000 });
+  expect(hasSelectedQuestion).toBe(true);
+});
diff --git a/tests/ui/scenario-form.test.jsx b/tests/ui/scenario-form.test.jsx
new file mode 100644
index 0000000..e08dcbc
--- /dev/null
+++ b/tests/ui/scenario-form.test.jsx
@@ -0,0 +1,190 @@
+import React from "react";
+import { describe, expect, it, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+import DiagnosticsView from "@/components/diagnostics-view.jsx";
+import SituationGraphView from "@/components/situation-graph-view.jsx";
+import {
+  ScenarioResultPanels,
+  submitScenarioForStartCase,
+} from "@/components/scenario-form.jsx";
+
+function makeGraphResult(overrides = {}) {
+  return {
+    success: true,
+    situationGraph: {
+      centralStatement: "Complaints increased while production increased.",
+      currentSummary:
+        "Nodes: 2 observation, 1 unknown | Edges: 2 total | Unknowns: 1 unresolved",
+      activeUnknownNodeId: "n-unknown",
+      resolvedNodeIds: [],
+      nodes: [
+        {
+          id: "n-1",
+          label: "Complaints up 35%",
+          description: "Complaints increased by 35%",
+          kind: "observation",
+          status: "supported",
+          confidence: "high",
+          value: 35,
+          unit: "%",
+        },
+        {
+          id: "n-2",
+          label: "Production up 40%",
+          description: "Production increased by 40%",
+          kind: "observation",
+          status: "supported",
+          confidence: "high",
+          value: 40,
+          unit: "%",
+        },
+        {
+          id: "n-unknown",
+          label: "Complaint rate denominator",
+          description: "Need the denominator for complaint rate",
+          kind: "unknown",
+          status: "unknown",
+          confidence: "medium",
+          value: null,
+          unit: null,
+        },
+      ],
+      edges: [
+        { id: "e1", fromNodeId: "n-1", toNodeId: "n-unknown" },
+        { id: "e2", fromNodeId: "n-2", toNodeId: "n-unknown" },
+      ],
+    },
+    selectedQuestion: {
+      question: "What denominator is being used for the complaint rate?",
+    },
+    diagnostics: {
+      modelName: "test",
+      responseDurationMs: 1234,
+      validationStatus: "valid",
+      promptVersion: "test-prompt",
+      nodeCount: 3,
+      edgeCount: 2,
+      graphReferenceValidation: { valid: true, errors: [] },
+    },
+    ...overrides,
+  };
+}
+
+describe("scenario-form UI helpers", () => {
+  it("submits to /api/cases/start", async () => {
+    const fetchImpl = vi.fn().mockResolvedValue({ ok: true });
+
+    await submitScenarioForStartCase(fetchImpl, "Scenario text");
+
+    expect(fetchImpl).toHaveBeenCalledWith(
+      "/api/cases/start",
+      expect.objectContaining({
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+      }),
+    );
+  });
+});
+
+describe("graph-backed UI rendering", () => {
+  it("renders central statement from successful graph response", () => {
+    const data = makeGraphResult();
+    const html = renderToStaticMarkup(
+      <SituationGraphView
+        situationGraph={data.situationGraph}
+        selectedQuestion={data.selectedQuestion}
+      />,
+    );
+
+    expect(html).toContain("Central statement");
+    expect(html).toContain("Complaints increased while production increased.");
+  });
+
+  it("renders active unknown", () => {
+    const data = makeGraphResult();
+    const html = renderToStaticMarkup(
+      <SituationGraphView
+        situationGraph={data.situationGraph}
+        selectedQuestion={data.selectedQuestion}
+      />,
+    );
+
+    expect(html).toContain("Active unknown");
+    expect(html).toContain("Complaint rate denominator");
+  });
+
+  it("renders selected question exactly once", () => {
+    const data = makeGraphResult();
+    const html = renderToStaticMarkup(
+      <SituationGraphView
+        situationGraph={data.situationGraph}
+        selectedQuestion={data.selectedQuestion}
+      />,
+    );
+
+    expect(
+      html.match(/What denominator is being used for the complaint rate\?/g) ||
+        [],
+    ).toHaveLength(1);
+  });
+
+  it("renders diagnostics", () => {
+    const html = renderToStaticMarkup(
+      <DiagnosticsView result={makeGraphResult()} />,
+    );
+
+    expect(html).toContain("Diagnostics");
+    expect(html).toContain("test");
+    expect(html).toContain("1234ms");
+    expect(html).toContain("Node count");
+    expect(html).toContain("Edge count");
+    expect(html).toContain("Graph references");
+  });
+
+  it("hides empty sections", () => {
+    const base = makeGraphResult();
+    const result = makeGraphResult({
+      selectedQuestion: null,
+      situationGraph: {
+        ...base.situationGraph,
+        activeUnknownNodeId: null,
+        nodes: [base.situationGraph.nodes[0]],
+        edges: [],
+      },
+    });
+
+    const html = renderToStaticMarkup(
+      <SituationGraphView
+        situationGraph={result.situationGraph}
+        selectedQuestion={result.selectedQuestion}
+      />,
+    );
+
+    expect(html).not.toContain("Selected Question");
+    expect(html).not.toContain("Active unknown");
+  });
+
+  it("displays API error clearly", () => {
+    const html = renderToStaticMarkup(
+      <ScenarioResultPanels
+        status="error"
+        result={{ error: "Invalid start-case request" }}
+      />,
+    );
+
+    expect(html).toContain("Error: Invalid start-case request");
+  });
+
+  it("renders expandable raw graph JSON", () => {
+    const data = makeGraphResult();
+    const html = renderToStaticMarkup(
+      <SituationGraphView
+        situationGraph={data.situationGraph}
+        selectedQuestion={data.selectedQuestion}
+      />,
+    );
+
+    expect(html).toContain("Raw graph JSON");
+    expect(html).toContain("&quot;centralStatement&quot;");
+  });
+});
\ No newline at end of file