fix: avoid opencode structured output session breakage

Replace server-enforced structured output with local JSON parsing for Git generation
Render generated commit and PR JSON responses as compact chat cards
Tighten generation prompts while preserving active session context

packages/ui/src/components/chat/message/parts/AssistantTextPart.tsx

@@ -6,6 +6,8 @@ import type { ContentChangeReason } from '@/hooks/useChatAutoFollow';
 import { useStreamingTextThrottle } from '../../hooks/useStreamingTextThrottle';
 import { resolveAssistantDisplayText, shouldRenderAssistantText } from './assistantTextVisibility';
 import { streamPerfCount, streamPerfObserve } from '@/stores/utils/streamDebug';
+import { GeneratedJsonResultCard } from './GeneratedJsonResultCard';
+import { parseGeneratedJsonResult } from './generatedJsonResult';
 
 type PartWithText = Part & { text?: string; content?: string; value?: string; time?: { start?: number; end?: number } };
 
@@ -71,6 +73,18 @@ const AssistantTextPart: React.FC<AssistantTextPartProps> = ({
         return null;
     }
 
+    const generatedResult = !isStreaming && isFinalized ? parseGeneratedJsonResult(displayTextContent) : null;
+    if (generatedResult) {
+        return (
+            <div
+                className={`group/assistant-text relative break-words ${chatRenderMode === 'live' ? 'my-1' : ''}`}
+                key={part.id || `${messageId}-text`}
+            >
+                <GeneratedJsonResultCard result={generatedResult} />
+            </div>
+        );
+    }
+
     return (
         <div
             className={`group/assistant-text relative break-words ${chatRenderMode === 'live' ? 'my-1' : ''}`}

packages/ui/src/components/chat/message/parts/GeneratedJsonResultCard.tsx

@@ -0,0 +1,80 @@
+import React from 'react';
+import { Button } from '@/components/ui/button';
+import { Icon } from '@/components/icon/Icon';
+import { copyTextToClipboard } from '@/lib/clipboard';
+import { useI18n } from '@/lib/i18n';
+import type { GeneratedResult } from './generatedJsonResult';
+
+export const GeneratedJsonResultCard: React.FC<{ result: GeneratedResult }> = ({ result }) => {
+  const { t } = useI18n();
+  const [copied, setCopied] = React.useState(false);
+
+  const copyText = React.useMemo(() => {
+    if (result.kind === 'commit') {
+      return [result.subject, ...result.highlights.map((highlight) => `- ${highlight}`)].join('\n');
+    }
+    return [result.title, result.body].filter(Boolean).join('\n\n');
+  }, [result]);
+
+  const handleCopy = React.useCallback(async () => {
+    const copyResult = await copyTextToClipboard(copyText || result.raw);
+    if (!copyResult.ok) return;
+    setCopied(true);
+    window.setTimeout(() => setCopied(false), 2000);
+  }, [copyText, result.raw]);
+
+  return (
+    <div data-component="generated-json-result" className="my-4 group overflow-hidden rounded-2xl border border-border/80 bg-[var(--surface-elevated)]">
+      <div className="flex items-center justify-between border-b border-border/70 px-3 py-1.5">
+        <span className="font-mono text-[13px] text-muted-foreground">
+          {result.kind === 'commit'
+            ? t('chat.generatedResult.commit.title')
+            : t('chat.generatedResult.pullRequest.title')}
+        </span>
+        <Button
+          type="button"
+          variant="ghost"
+          size="xs"
+          onClick={() => { void handleCopy(); }}
+          title={copied ? t('chat.generatedResult.actions.copied') : t('chat.generatedResult.actions.copy')}
+          aria-label={copied ? t('chat.generatedResult.actions.copied') : t('chat.generatedResult.actions.copy')}
+          className="text-muted-foreground hover:text-foreground md:opacity-0 md:group-hover:opacity-100"
+        >
+          {copied ? <Icon name="check" className="size-3.5" /> : <Icon name="file-copy" className="size-3.5" />}
+        </Button>
+      </div>
+      <div className="space-y-3 px-3 py-3">
+        {result.kind === 'commit' ? (
+          <>
+            <div className="typography-ui-label text-foreground">{result.subject}</div>
+            {result.highlights.length > 0 ? (
+              <ul className="space-y-1 text-sm text-muted-foreground">
+                {result.highlights.map((highlight, index) => (
+                  <li key={`${index}-${highlight}`} className="flex gap-2">
+                    <span className="text-muted-foreground/70">-</span>
+                    <span>{highlight}</span>
+                  </li>
+                ))}
+              </ul>
+            ) : null}
+          </>
+        ) : (
+          <>
+            {result.title ? (
+              <div>
+                <div className="typography-micro uppercase tracking-[0.12em] text-muted-foreground">{t('chat.generatedResult.pullRequest.titleLabel')}</div>
+                <div className="mt-1 typography-ui-label text-foreground">{result.title}</div>
+              </div>
+            ) : null}
+            {result.body ? (
+              <div>
+                <div className="typography-micro uppercase tracking-[0.12em] text-muted-foreground">{t('chat.generatedResult.pullRequest.bodyLabel')}</div>
+                <pre className="mt-1 whitespace-pre-wrap break-words text-sm leading-relaxed text-muted-foreground font-sans">{result.body}</pre>
+              </div>
+            ) : null}
+          </>
+        )}
+      </div>
+    </div>
+  );
+};

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

@@ -0,0 +1,67 @@
+export type GeneratedCommitResult = {
+  kind: 'commit';
+  subject: string;
+  highlights: string[];
+  raw: string;
+};
+
+export type GeneratedPrResult = {
+  kind: 'pr';
+  title: string;
+  body: string;
+  raw: string;
+};
+
+export type GeneratedResult = GeneratedCommitResult | GeneratedPrResult;
+
+const parseJsonObjects = (value: string): Record<string, unknown>[] => {
+  const text = value.trim();
+  const candidates = new Set<string>();
+
+  const fencedMatches = text.matchAll(/```(?:json)?\s*([\s\S]*?)```/gi);
+  for (const match of fencedMatches) {
+    if (match[1]) candidates.add(match[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;
+      }
+    }
+  }
+
+  const parsed: Record<string, unknown>[] = [];
+  for (const candidate of candidates) {
+    try {
+      const item = JSON.parse(candidate) as unknown;
+      if (item && typeof item === 'object' && !Array.isArray(item)) {
+        parsed.push(item as Record<string, unknown>);
+      }
+    } catch {
+      // Ignore non-JSON prose; the model may include markdown before the object.
+    }
+  }
+  return parsed;
+};
+
+export const parseGeneratedJsonResult = (value: string): GeneratedResult | null => {
+  for (const item of parseJsonObjects(value)) {
+    const subject = typeof item.subject === 'string' ? item.subject.trim() : '';
+    const highlights = Array.isArray(item.highlights)
+      ? item.highlights.filter((entry) => typeof entry === 'string').map((entry) => entry.trim()).filter(Boolean).slice(0, 3)
+      : [];
+    if (subject) {
+      return { kind: 'commit', subject, highlights, raw: JSON.stringify({ subject, highlights }, null, 2) };
+    }
+
+    const title = typeof item.title === 'string' ? item.title.trim() : '';
+    const body = typeof item.body === 'string' ? item.body.trim() : '';
+    if (title || body) {
+      return { kind: 'pr', title, body, raw: JSON.stringify({ title, body }, null, 2) };
+    }
+  }
+  return null;
+};