diff --git a/agents/ai_analyst.py b/agents/ai_analyst.py
new file mode 100644
index 0000000..e614027
--- /dev/null
+++ b/agents/ai_analyst.py
@@ -0,0 +1,65 @@
+import json
+import logging
+from anthropic import Anthropic
+
+logger = logging.getLogger(__name__)
+
+class AIAgent:
+    def __init__(self, api_key: str):
+        self.client = Anthropic(api_key=api_key) if api_key else None
+
+    def analyze_batch(self, coins_data: list[dict]) -> dict[str, dict]:
+        if not coins_data or not self.client:
+            return {c.get("symbol",""): {"score": 50, "summary": "AI not configured"} for c in coins_data}
+
+        prompt = self._build_prompt(coins_data)
+        try:
+            response = self.client.messages.create(
+                model="claude-sonnet-4-20250514",
+                max_tokens=2000,
+                messages=[{"role": "user", "content": prompt}],
+            )
+            return self._parse_response(response.content[0].text, coins_data)
+        except Exception as e:
+            logger.error(f"AI analysis failed: {e}")
+            return {c["symbol"]: {"score": 50, "summary": "Analysis unavailable"} for c in coins_data}
+
+    def _build_prompt(self, coins_data: list[dict]) -> str:
+        coins_text = ""
+        for coin in coins_data:
+            coins_text += f"""
+Coin: {coin['symbol']}
+- Price: ${coin.get('price', 'N/A')}
+- 24h Change: {coin.get('change_pct', 'N/A')}%
+- Technical Score: {coin.get('technical_score', 'N/A')}/100
+- News Sentiment: {coin.get('news_score', 'N/A')}/100
+- Social Sentiment: {coin.get('social_score', 'N/A')}/100
+- Recent Headlines: {', '.join(coin.get('headlines', [])[:3])}
+"""
+        return f"""You are a crypto market analyst. Analyze these coins for short-term (24h) spot trading potential.
+
+For each coin, provide:
+1. A score from 0-100 (0=strong sell, 50=neutral, 100=strong buy)
+2. A brief 1-2 sentence summary explaining your reasoning
+
+{coins_text}
+
+Respond in JSON format:
+{{
+  "SYMBOL": {{"score": NUMBER, "summary": "TEXT"}},
+  ...
+}}
+
+Only output the JSON, no other text."""
+
+    def _parse_response(self, text: str, coins_data: list[dict]) -> dict[str, dict]:
+        try:
+            text = text.strip()
+            if text.startswith("```"):
+                text = text.split("```")[1]
+                if text.startswith("json"):
+                    text = text[4:]
+            return json.loads(text)
+        except (json.JSONDecodeError, IndexError) as e:
+            logger.warning(f"Failed to parse AI response: {e}")
+            return {c["symbol"]: {"score": 50, "summary": "Parse error"} for c in coins_data}
diff --git a/engine/portfolio.py b/engine/portfolio.py
new file mode 100644
index 0000000..73a9471
--- /dev/null
+++ b/engine/portfolio.py
@@ -0,0 +1,114 @@
+import logging
+from datetime import datetime, timezone
+from config import MAX_POSITIONS, MIN_POSITION_USD, STOP_LOSS_PCT, TAKE_PROFIT_1_PCT, TAKE_PROFIT_2_PCT
+
+logger = logging.getLogger(__name__)
+
+class PortfolioManager:
+    def __init__(self, initial_capital: float = 200.0):
+        self.initial_capital = initial_capital
+        self.cash = initial_capital
+        self.positions: dict[str, dict] = {}
+        self.trades: list[dict] = []
+
+    def buy(self, symbol: str, price: float, score: float) -> bool:
+        if symbol in self.positions:
+            return False
+        if len(self.positions) >= MAX_POSITIONS:
+            return False
+        amount = self._position_size(score)
+        if amount < MIN_POSITION_USD:
+            return False
+        if amount > self.cash:
+            amount = self.cash
+        if amount < MIN_POSITION_USD:
+            return False
+        quantity = amount / price
+        self.cash -= amount
+        self.positions[symbol] = {
+            "entry_price": price, "quantity": quantity,
+            "invested_usd": amount, "tp1_hit": False,
+            "opened_at": datetime.now(timezone.utc).isoformat(),
+        }
+        self.trades.append({
+            "coin": symbol, "side": "BUY", "price": price,
+            "quantity": quantity, "amount_usd": amount,
+            "timestamp": datetime.now(timezone.utc).isoformat(), "reason": "signal",
+        })
+        return True
+
+    def sell(self, symbol: str, price: float, reason: str = "signal", partial: float = 1.0):
+        if symbol not in self.positions:
+            return
+        pos = self.positions[symbol]
+        sell_qty = pos["quantity"] * partial
+        sell_usd = sell_qty * price
+        self.cash += sell_usd
+        self.trades.append({
+            "coin": symbol, "side": "SELL", "price": price,
+            "quantity": sell_qty, "amount_usd": sell_usd,
+            "timestamp": datetime.now(timezone.utc).isoformat(), "reason": reason,
+        })
+        if partial >= 1.0:
+            del self.positions[symbol]
+        else:
+            pos["quantity"] -= sell_qty
+
+    def check_exit(self, symbol: str, current_price: float):
+        if symbol not in self.positions:
+            return
+        pos = self.positions[symbol]
+        entry = pos["entry_price"]
+        change_pct = (current_price - entry) / entry
+        if change_pct <= STOP_LOSS_PCT:
+            self.sell(symbol, current_price, reason="stop-loss")
+            return
+        if change_pct >= TAKE_PROFIT_2_PCT:
+            self.sell(symbol, current_price, reason="take-profit-2")
+            return
+        if change_pct >= TAKE_PROFIT_1_PCT and not pos["tp1_hit"]:
+            pos["tp1_hit"] = True
+            self.sell(symbol, current_price, reason="take-profit-1", partial=0.5)
+
+    def _position_size(self, score: float) -> float:
+        if score >= 90:
+            pct = 0.30
+        elif score >= 80:
+            pct = 0.20
+        else:
+            pct = 0.15
+        return round(self.cash * pct, 2)
+
+    def get_portfolio_value(self, current_prices: dict[str, float]) -> dict:
+        holdings_value = sum(
+            pos["quantity"] * current_prices.get(sym, pos["entry_price"])
+            for sym, pos in self.positions.items()
+        )
+        total_value = self.cash + holdings_value
+        total_pnl = total_value - self.initial_capital
+        pnl_pct = (total_pnl / self.initial_capital) * 100
+
+        winning = sum(1 for t in self.trades if t["side"] == "SELL" and self._trade_pnl(t) > 0)
+        total_sells = sum(1 for t in self.trades if t["side"] == "SELL")
+        win_rate = (winning / total_sells * 100) if total_sells > 0 else 0
+
+        return {
+            "total_value": round(total_value, 2),
+            "cash": round(self.cash, 2),
+            "holdings_value": round(holdings_value, 2),
+            "total_pnl": round(total_pnl, 2),
+            "pnl_pct": round(pnl_pct, 2),
+            "win_rate": round(win_rate, 1),
+            "open_positions": len(self.positions),
+        }
+
+    def _trade_pnl(self, sell_trade: dict) -> float:
+        matching_buys = [
+            t for t in self.trades
+            if t["coin"] == sell_trade["coin"] and t["side"] == "BUY"
+            and t["timestamp"] <= sell_trade["timestamp"]
+        ]
+        if matching_buys:
+            latest_buy = matching_buys[-1]
+            return (sell_trade["price"] - latest_buy["price"]) * sell_trade["quantity"]
+        return 0
diff --git a/engine/signal.py b/engine/signal.py
new file mode 100644
index 0000000..6dd287e
--- /dev/null
+++ b/engine/signal.py
@@ -0,0 +1,45 @@
+from config import DEFAULT_WEIGHTS
+
+class SignalEngine:
+    def __init__(self):
+        self.weights = dict(DEFAULT_WEIGHTS)
+
+    def set_weights(self, weights: dict):
+        total = sum(weights.values())
+        if abs(total - 1.0) > 0.01:
+            raise ValueError(f"Weights must sum to 1.0, got {total}")
+        self.weights = weights
+
+    def compute_score(self, technical: float, news: float, social: float, ai: float) -> float:
+        score = (
+            technical * self.weights["technical"]
+            + news * self.weights["news"]
+            + social * self.weights["social"]
+            + ai * self.weights["ai"]
+        )
+        return round(score, 1)
+
+    def classify(self, score: float) -> str:
+        if score >= 70:
+            return "BUY"
+        elif score >= 40:
+            return "HOLD"
+        return "SELL"
+
+    def rank_coins(self, coins: dict[str, dict]) -> list[dict]:
+        results = []
+        for symbol, scores in coins.items():
+            composite = self.compute_score(
+                scores["technical"], scores["news"], scores["social"], scores["ai"]
+            )
+            results.append({
+                "symbol": symbol,
+                "technical": scores["technical"],
+                "news": scores["news"],
+                "social": scores["social"],
+                "ai": scores["ai"],
+                "composite": composite,
+                "signal": self.classify(composite),
+            })
+        results.sort(key=lambda x: x["composite"], reverse=True)
+        return results
diff --git a/engine/surge.py b/engine/surge.py
new file mode 100644
index 0000000..f79963b
--- /dev/null
+++ b/engine/surge.py
@@ -0,0 +1,20 @@
+import logging
+
+logger = logging.getLogger(__name__)
+
+class SurgeDetector:
+    def __init__(self, multiplier: float = 3.0):
+        self.multiplier = multiplier
+
+    def detect(self, tickers: list[dict], avg_volumes: dict[str, float]) -> list[str]:
+        surged = []
+        for t in tickers:
+            symbol = t["symbol"]
+            if not symbol.endswith("USDT"):
+                continue
+            current_vol = float(t.get("quoteVolume", 0))
+            avg_vol = avg_volumes.get(symbol, 0)
+            if avg_vol > 0 and current_vol >= avg_vol * self.multiplier:
+                logger.info(f"Surge detected: {symbol} volume {current_vol:.0f} vs avg {avg_vol:.0f}")
+                surged.append(symbol)
+        return surged
diff --git a/tests/test_portfolio.py b/tests/test_portfolio.py
new file mode 100644
index 0000000..9b52886
--- /dev/null
+++ b/tests/test_portfolio.py
@@ -0,0 +1,62 @@
+import pytest
+from engine.portfolio import PortfolioManager
+
+@pytest.fixture
+def pm():
+    return PortfolioManager(initial_capital=200.0)
+
+def test_initial_state(pm):
+    assert pm.cash == 200.0
+    assert pm.positions == {}
+    assert pm.trades == []
+
+def test_buy(pm):
+    pm.buy("BTCUSDT", price=40000.0, score=85)
+    assert "BTCUSDT" in pm.positions
+    assert pm.cash < 200.0
+    assert len(pm.trades) == 1
+    assert pm.trades[0]["side"] == "BUY"
+
+def test_buy_size_by_score(pm):
+    pm.buy("SOLUSDT", price=140.0, score=75)
+    assert abs(pm.trades[0]["amount_usd"] - 30.0) < 0.01
+
+def test_buy_respects_max_positions(pm):
+    for i, coin in enumerate(["A", "B", "C", "D", "E"]):
+        pm.buy(f"{coin}USDT", price=10.0, score=80)
+    pm.buy("FUSDT", price=10.0, score=80)
+    assert len(pm.positions) == 5
+
+def test_buy_respects_min_position(pm):
+    pm.cash = 10.0
+    pm.buy("BTCUSDT", price=40000.0, score=85)
+    assert "BTCUSDT" not in pm.positions
+
+def test_sell_full(pm):
+    pm.buy("ETHUSDT", price=3500.0, score=80)
+    invested = pm.positions["ETHUSDT"]["invested_usd"]
+    pm.sell("ETHUSDT", price=3800.0, reason="signal")
+    assert "ETHUSDT" not in pm.positions
+    assert pm.cash > 200.0 - invested
+
+def test_stop_loss(pm):
+    pm.buy("DOGEUSDT", price=0.10, score=80)
+    pm.check_exit("DOGEUSDT", current_price=0.091)
+    assert "DOGEUSDT" not in pm.positions
+
+def test_take_profit_partial(pm):
+    pm.buy("SOLUSDT", price=100.0, score=80)
+    qty_before = pm.positions["SOLUSDT"]["quantity"]
+    pm.check_exit("SOLUSDT", current_price=116.0)
+    assert pm.positions["SOLUSDT"]["quantity"] < qty_before
+
+def test_take_profit_full(pm):
+    pm.buy("SOLUSDT", price=100.0, score=80)
+    pm.check_exit("SOLUSDT", current_price=126.0)
+    assert "SOLUSDT" not in pm.positions
+
+def test_pnl_calculation(pm):
+    pm.buy("ETHUSDT", price=3500.0, score=80)
+    pnl = pm.get_portfolio_value({"ETHUSDT": 3800.0})
+    assert pnl["total_pnl"] > 0
+    assert pnl["total_value"] > 200.0
diff --git a/tests/test_signal.py b/tests/test_signal.py
new file mode 100644
index 0000000..477ecb2
--- /dev/null
+++ b/tests/test_signal.py
@@ -0,0 +1,39 @@
+import pytest
+from engine.signal import SignalEngine
+
+@pytest.fixture
+def engine():
+    return SignalEngine()
+
+def test_compute_score_default_weights(engine):
+    score = engine.compute_score(80, 60, 70, 50)
+    assert score == 72.0
+
+def test_classify_buy(engine):
+    assert engine.classify(75) == "BUY"
+
+def test_classify_hold(engine):
+    assert engine.classify(55) == "HOLD"
+
+def test_classify_sell(engine):
+    assert engine.classify(30) == "SELL"
+
+def test_custom_weights(engine):
+    engine.set_weights({"technical": 0.4, "news": 0.3, "social": 0.2, "ai": 0.1})
+    score = engine.compute_score(80, 60, 70, 50)
+    assert score == 69.0
+
+def test_weights_must_sum_to_one(engine):
+    with pytest.raises(ValueError):
+        engine.set_weights({"technical": 0.5, "news": 0.3, "social": 0.1, "ai": 0.2})
+
+def test_rank_coins(engine):
+    coins = {
+        "BTC": {"technical": 80, "news": 70, "social": 60, "ai": 75},
+        "ETH": {"technical": 90, "news": 80, "social": 70, "ai": 85},
+        "DOGE": {"technical": 30, "news": 25, "social": 40, "ai": 20},
+    }
+    ranked = engine.rank_coins(coins)
+    assert ranked[0]["symbol"] == "ETH"
+    assert ranked[-1]["symbol"] == "DOGE"
+    assert ranked[-1]["signal"] == "SELL"
diff --git a/tests/test_surge.py b/tests/test_surge.py
new file mode 100644
index 0000000..8556181
--- /dev/null
+++ b/tests/test_surge.py
@@ -0,0 +1,21 @@
+import pytest
+from engine.surge import SurgeDetector
+
+def test_detect_surge():
+    detector = SurgeDetector(multiplier=3.0)
+    tickers = [
+        {"symbol": "BTCUSDT", "quoteVolume": "1000000"},
+        {"symbol": "NEWUSDT", "quoteVolume": "5000000"},
+        {"symbol": "ETHUSDT", "quoteVolume": "800000"},
+    ]
+    avg_volumes = {"BTCUSDT": 900000, "NEWUSDT": 1000000, "ETHUSDT": 750000}
+    surged = detector.detect(tickers, avg_volumes)
+    assert "NEWUSDT" in surged
+    assert "BTCUSDT" not in surged
+
+def test_no_surge():
+    detector = SurgeDetector(multiplier=3.0)
+    tickers = [{"symbol": "BTCUSDT", "quoteVolume": "1000000"}]
+    avg_volumes = {"BTCUSDT": 900000}
+    surged = detector.detect(tickers, avg_volumes)
+    assert len(surged) == 0