Fee buffer and error isolation

bot.py

@@ -160,11 +160,12 @@ def run_cycle(config: Config) -> bool:
         return bool(closed)
 
     to_buy = opportunities[:num_to_buy]
-    # Split available balance equally across the chosen assets (always >= min_order_usd)
+    # Deduct fee reserve before splitting so each order has room for Kraken's taker fee
-    alloc_per_asset = balance / num_to_buy
+    fee_multiplier = 1 - (config.taker_fee_pct / 100)
+    alloc_per_asset = (balance * fee_multiplier) / num_to_buy
     log.info(
-        "Buying %d asset(s) @ $%.2f each (total $%.2f)",
+        "Buying %d asset(s) @ $%.2f each (total $%.2f, %.1f%% fee reserve applied)",
-        num_to_buy, alloc_per_asset, alloc_per_asset * num_to_buy,
+        num_to_buy, alloc_per_asset, alloc_per_asset * num_to_buy, config.taker_fee_pct,
     )
 
     for opp in to_buy:
@@ -177,7 +178,11 @@ def run_cycle(config: Config) -> bool:
             )
             continue
 
-        order_id = client.market_buy(opp.pair, quantity, paper=config.paper_trading)
+        try:
+            order_id = client.market_buy(opp.pair, quantity, paper=config.paper_trading)
+        except KrakenError as exc:
+            log.error("Order failed for %s: %s — skipping", opp.pair, exc)
+            continue
 
         portfolio.add(Position(
             pair=opp.pair,

config.py

@@ -23,6 +23,7 @@ class Config:
     # Portfolio limits
     max_positions: int = 5        # Maximum concurrent holdings
     min_order_usd: float = 15.0   # Kraken minimum is ~$10; keep a small buffer
+    taker_fee_pct: float = 0.4    # Reserve this % per order for Kraken's taker fee (actual ~0.26%)
 
     # ── Risk management ──────────────────────────────────────────────────────
     # Trailing stop: sell if price drops this % below its peak since purchase.