fix: prevent embedded JSON examples from rendering as result cards

Only parse full-message generated JSON results
Keep markdown prose with JSON examples rendered normally
Add regression coverage for embedded JSON examples

packages/ui/src/components/chat/message/parts/generatedJsonResult.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, test } from 'bun:test';
+
+import { parseGeneratedJsonResult } from './generatedJsonResult';
+
+describe('parseGeneratedJsonResult', () => {
+  test('parses a full pull request JSON result', () => {
+    expect(parseGeneratedJsonResult('{"title":"Side task","body":"Details"}')).toEqual({
+      kind: 'pr',
+      title: 'Side task',
+      body: 'Details',
+      raw: JSON.stringify({ title: 'Side task', body: 'Details' }, null, 2),
+    });
+  });
+
+  test('parses a full fenced JSON result', () => {
+    expect(parseGeneratedJsonResult('```json\n{"subject":"Fix parser","highlights":["Narrow detection"]}\n```')).toEqual({
+      kind: 'commit',
+      subject: 'Fix parser',
+      highlights: ['Narrow detection'],
+      raw: JSON.stringify({ subject: 'Fix parser', highlights: ['Narrow detection'] }, null, 2),
+    });
+  });
+
+  test('ignores JSON examples embedded in markdown prose', () => {
+    const markdown = [
+      'Recommended endpoint:',
+      '',
+      '```json',
+      '{',
+      '  "title": "Side task",',
+      '  "prompt": "Investigate X"',
+      '}',
+      '```',
+      '',
+      'This should stay markdown.',
+    ].join('\n');
+
+    expect(parseGeneratedJsonResult(markdown)).toBeNull();
+  });
+});

packages/ui/src/components/chat/message/parts/generatedJsonResult.ts

@@ -16,21 +16,15 @@ export type GeneratedResult = GeneratedCommitResult | GeneratedPrResult;
 
 const parseJsonObjects = (value: string): Record<string, unknown>[] => {
   const text = value.trim();
-  const candidates = new Set<string>();
+  const candidates: string[] = [];
 
-  const fencedMatches = text.matchAll(/```(?:json)?\s*([\s\S]*?)```/gi);
-  for (const match of fencedMatches) {
-    if (match[1]) candidates.add(match[1].trim());
+  const fencedMatch = text.match(/^```(?:json)?\s*([\s\S]*?)```$/i);
+  if (fencedMatch?.[1]) {
+    candidates.push(fencedMatch[1].trim());
   }
 
-  const firstObjectStart = text.indexOf('{');
-  if (firstObjectStart >= 0) {
-    for (let end = text.length; end > firstObjectStart; end -= 1) {
-      if (text[end - 1] === '}') {
-        candidates.add(text.slice(firstObjectStart, end));
-        break;
-      }
-    }
+  if (text.startsWith('{') && text.endsWith('}')) {
+    candidates.push(text);
   }
 
   const parsed: Record<string, unknown>[] = [];