diff --git a/server.js b/server.js
index a0f686e..4229d2e 100644
--- a/server.js
+++ b/server.js
@@ -17,9 +17,12 @@ app.get(['/q', '/q.html'], (_req, res) => res.sendFile(path.join(PUBLIC_DIR, 'q'
 app.use(express.static(PUBLIC_DIR));
 
 const MODELS = {
+    opus: 'claude-opus-4-7',
     sonnet: 'claude-sonnet-4-6',
     haiku: 'claude-haiku-4-5-20251001',
 };
+const THINKING_MODELS = new Set(['claude-opus-4-7']);
+const THINKING_BUDGET_TOKENS = 16000; // "high effort"
 
 const CONFIG_DIR = process.env.CLAUDE_CONFIG_DIR || path.join(os.homedir(), '.claude');
 const CREDS_PATH = path.join(CONFIG_DIR, '.credentials.json');
@@ -108,6 +111,16 @@ const SYSTEM_PROMPT = [
 ].join("\n");
 
 async function callClaude(modelId, content, accessToken) {
+    const body = {
+        model: modelId,
+        max_tokens: THINKING_MODELS.has(modelId) ? THINKING_BUDGET_TOKENS + 4096 : 8192,
+        stream: true,
+        system: SYSTEM_PROMPT,
+        messages: [{ role: 'user', content }],
+    };
+    if (THINKING_MODELS.has(modelId)) {
+        body.thinking = { type: 'enabled', budget_tokens: THINKING_BUDGET_TOKENS };
+    }
     return fetch('https://api.anthropic.com/v1/messages', {
         method: 'POST',
         dispatcher: anthropicAgent,
@@ -119,18 +132,12 @@ async function callClaude(modelId, content, accessToken) {
             'x-app': 'cli',
             'User-Agent': 'claude-cli/2.1.114',
         },
-        body: JSON.stringify({
-            model: modelId,
-            max_tokens: 8192,
-            stream: true,
-            system: SYSTEM_PROMPT,
-            messages: [{ role: 'user', content }],
-        }),
+        body: JSON.stringify(body),
     });
 }
 
 app.post('/api/chat', express.json({ limit: '50mb' }), async (req, res) => {
-    const { text, model = 'sonnet', image, images } = req.body;
+    const { text, model = 'opus', image, images } = req.body;
     const hasText = text?.trim();
     const imgList = Array.isArray(images) ? images : (image ? [image] : []);
     if (!hasText && imgList.length === 0) return res.status(400).json({ error: 'text or image required' });
@@ -210,12 +217,13 @@ app.post('/api/chat', express.json({ limit: '50mb' }), async (req, res) => {
 const CC_SYSTEM_PREFIX = "You are Claude Code, Anthropic's official CLI for Claude.";
 
 function mapModel(name) {
-    if (!name) return MODELS.sonnet;
+    if (!name) return MODELS.opus;
     const n = String(name).toLowerCase();
+    if (n.includes('opus')) return MODELS.opus;
     if (n.includes('haiku')) return MODELS.haiku;
     if (n.includes('sonnet')) return MODELS.sonnet;
     if (MODELS[n]) return MODELS[n];
-    return MODELS.sonnet;
+    return MODELS.opus;
 }
 
 function translateContent(content) {
@@ -270,10 +278,11 @@ app.post('/v1/chat/completions', express.json({ limit: '50mb' }), async (req, re
             },
             body: JSON.stringify({
                 model: modelId,
-                max_tokens,
+                max_tokens: THINKING_MODELS.has(modelId) ? Math.max(max_tokens, THINKING_BUDGET_TOKENS + 2048) : max_tokens,
                 stream: false,
                 system: systemParts.join('\n\n'),
                 messages: anthMessages,
+                ...(THINKING_MODELS.has(modelId) ? { thinking: { type: 'enabled', budget_tokens: THINKING_BUDGET_TOKENS } } : {}),
             }),
         });