diff --git a/package.json b/package.json
index 0f57120..1c55221 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
     "start": "node server.js"
   },
   "dependencies": {
+    "@anthropic-ai/sdk": "^0.39.0",
     "express": "^4.19.2"
   }
 }
diff --git a/server.js b/server.js
index 60149fc..4765fef 100644
--- a/server.js
+++ b/server.js
@@ -1,84 +1,79 @@
 const express = require('express');
-const { spawn, execSync } = require('child_process');
 const path = require('path');
 const fs = require('fs');
 const os = require('os');
+const { createRequire } = require('module');
 
 const app = express();
 app.use(express.json({ limit: '10mb' }));
 app.use(express.static(path.join(__dirname, 'public')));
 
-// Resolve claude binary
-let CLAUDE_BIN = 'claude';
-{
-    const local = '/app/claude-bin/node_modules/.bin/claude';
-    if (fs.existsSync(local)) {
-        CLAUDE_BIN = local;
-    } else {
-        try {
-            CLAUDE_BIN = execSync('which claude 2>/dev/null || echo claude', { encoding: 'utf8' }).trim();
-        } catch (e) {}
-    }
-}
-console.log(`✓ Claude binary: ${CLAUDE_BIN}`);
-
 const MODELS = {
     sonnet: 'claude-sonnet-4-6',
     haiku: 'claude-haiku-4-5-20251001',
 };
 
-app.post('/api/chat', (req, res) => {
+function getAccessToken() {
+    const configDir = process.env.CLAUDE_CONFIG_DIR || path.join(os.homedir(), '.claude');
+    const credsPath = path.join(configDir, '.credentials.json');
+    try {
+        const creds = JSON.parse(fs.readFileSync(credsPath, 'utf8'));
+        return creds?.claudeAiOauth?.accessToken || null;
+    } catch (e) {
+        return null;
+    }
+}
+
+function createClient(accessToken) {
+    const Anthropic = require('@anthropic-ai/sdk');
+    // OAuth token: use as apiKey — SDK sends x-api-key header
+    // Some versions also support authToken for Bearer auth
+    try {
+        return new Anthropic({ authToken: accessToken });
+    } catch (e) {
+        return new Anthropic({ apiKey: accessToken });
+    }
+}
+
+app.post('/api/chat', async (req, res) => {
     const { text, model = 'sonnet' } = req.body;
     if (!text?.trim()) return res.status(400).json({ error: 'text required' });
 
     const modelId = MODELS[model] || MODELS.sonnet;
-    const configDir = process.env.CLAUDE_CONFIG_DIR || path.join(os.homedir(), '.claude');
+    const accessToken = getAccessToken();
+
+    if (!accessToken) {
+        return res.status(500).json({ error: 'No credentials found in ' + (process.env.CLAUDE_CONFIG_DIR || '~/.claude') });
+    }
 
     res.setHeader('Content-Type', 'text/event-stream');
     res.setHeader('Cache-Control', 'no-cache');
     res.setHeader('Connection', 'keep-alive');
-    res.flushHeaders(); // establish SSE connection immediately
+    res.flushHeaders();
 
-    const env = { ...process.env, CLAUDE_CONFIG_DIR: configDir };
-
-    // heartbeat to keep connection alive during long generation
     const heartbeat = setInterval(() => res.write(': ping\n\n'), 15000);
 
-    const proc = spawn(CLAUDE_BIN, ['-p', text, '--model', modelId, '--output-format', 'text'], {
-        env,
-        stdio: ['ignore', 'pipe', 'pipe'],
-    });
+    try {
+        const client = createClient(accessToken);
+        const stream = await client.messages.stream({
+            model: modelId,
+            max_tokens: 8192,
+            messages: [{ role: 'user', content: text }],
+        });
 
-    proc.stdout.on('data', (chunk) => {
-        res.write(`data: ${JSON.stringify({ text: chunk.toString() })}\n\n`);
-    });
-
-    let stderrBuf = '';
-    proc.stderr.on('data', (chunk) => {
-        const s = chunk.toString();
-        stderrBuf += s;
-        console.error('[claude stderr]', s.substring(0, 500));
-    });
-
-    proc.on('error', (err) => {
-        console.error('[spawn error]', err.message);
-        res.write(`data: ${JSON.stringify({ error: `spawn: ${err.message}` })}\n\n`);
-    });
-
-    proc.on('close', (code, signal) => {
-        clearInterval(heartbeat);
-        console.log(`[claude close] code=${code} signal=${signal} stderr=${stderrBuf.substring(0,300)}`);
-        if (code !== 0) {
-            const msg = stderrBuf.trim() || `code=${code} signal=${signal}`;
-            res.write(`data: ${JSON.stringify({ error: msg.substring(0, 500) })}\n\n`);
+        for await (const event of stream) {
+            if (event.type === 'content_block_delta' && event.delta?.type === 'text_delta') {
+                res.write(`data: ${JSON.stringify({ text: event.delta.text })}\n\n`);
+            }
         }
+    } catch (err) {
+        console.error('[api error]', err.message);
+        res.write(`data: ${JSON.stringify({ error: err.message })}\n\n`);
+    } finally {
+        clearInterval(heartbeat);
         res.write('data: [DONE]\n\n');
         res.end();
-    });
-
-    let finished = false;
-    proc.on('close', () => { finished = true; });
-    res.on('close', () => { clearInterval(heartbeat); if (!finished) try { proc.kill(); } catch (e) {} });
+    }
 });
 
 app.listen(8108, () => console.log('sechenov :8108'));