diff --git a/tools/build-mainnet-chainspec.sh b/tools/build-mainnet-chainspec.sh
new file mode 100755
index 00000000..82285cb8
--- /dev/null
+++ b/tools/build-mainnet-chainspec.sh
@@ -0,0 +1,242 @@
+#!/bin/bash
+# =============================================================================
+# PEZKUWICHAIN MAINNET CHAIN SPEC BUILDER
+# =============================================================================
+# Bu script mainnet chain spec'ini doğru şekilde oluşturur:
+# 1. Relay chain spec (num_cores: 2 ile)
+# 2. Asset Hub (para 1000) genesis_head + validation_code
+# 3. People Chain (para 1004) genesis_head + validation_code
+# 4. Raw format'a çevirir
+# =============================================================================
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+SDK_ROOT="$(dirname "$SCRIPT_DIR")"
+OUTPUT_DIR="${1:-$SDK_ROOT/chainspecs}"
+
+PEZKUWI_BIN="$SDK_ROOT/target/release/pezkuwi"
+TEYRCHAIN_BIN="$SDK_ROOT/target/release/pezkuwi-teyrchain"
+
+# Colors
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m'
+
+echo -e "${GREEN}=== PEZKUWICHAIN MAINNET CHAIN SPEC BUILDER ===${NC}"
+echo "SDK Root: $SDK_ROOT"
+echo "Output Dir: $OUTPUT_DIR"
+echo ""
+
+# Check binaries
+if [ ! -f "$PEZKUWI_BIN" ]; then
+    echo -e "${RED}ERROR: pezkuwi binary not found at $PEZKUWI_BIN${NC}"
+    echo "Run: cargo build --release -p pezkuwi"
+    exit 1
+fi
+
+if [ ! -f "$TEYRCHAIN_BIN" ]; then
+    echo -e "${RED}ERROR: pezkuwi-teyrchain binary not found at $TEYRCHAIN_BIN${NC}"
+    echo "Run: cargo build --release -p pezkuwi-teyrchain"
+    exit 1
+fi
+
+mkdir -p "$OUTPUT_DIR"
+
+# Temp files for large data
+TEMP_DIR=$(mktemp -d)
+trap "rm -rf $TEMP_DIR" EXIT
+
+# =============================================================================
+# STEP 1: Generate relay chain plain spec
+# =============================================================================
+echo -e "${YELLOW}[1/6] Generating relay chain plain spec...${NC}"
+$PEZKUWI_BIN build-spec \
+    --chain pezkuwichain-mainnet \
+    --disable-default-bootnode \
+    2>/dev/null > "$OUTPUT_DIR/relay-plain.json"
+echo -e "${GREEN}  -> relay-plain.json created${NC}"
+
+# =============================================================================
+# STEP 2: Generate Asset Hub chain spec
+# =============================================================================
+echo -e "${YELLOW}[2/6] Generating Asset Hub chain spec...${NC}"
+$TEYRCHAIN_BIN build-spec \
+    --chain asset-hub-pezkuwichain \
+    --disable-default-bootnode \
+    2>/dev/null > "$OUTPUT_DIR/asset-hub-plain.json"
+echo -e "${GREEN}  -> asset-hub-plain.json created${NC}"
+
+# =============================================================================
+# STEP 3: Generate People Chain chain spec
+# =============================================================================
+echo -e "${YELLOW}[3/6] Generating People Chain chain spec...${NC}"
+$TEYRCHAIN_BIN build-spec \
+    --chain people-pezkuwichain \
+    --disable-default-bootnode \
+    2>/dev/null > "$OUTPUT_DIR/people-plain.json"
+echo -e "${GREEN}  -> people-plain.json created${NC}"
+
+# =============================================================================
+# STEP 4: Export genesis data and add to relay spec
+# =============================================================================
+echo -e "${YELLOW}[4/6] Exporting genesis data and adding paras to relay spec...${NC}"
+
+# Export to temp files (to avoid shell variable size limits)
+$TEYRCHAIN_BIN export-genesis-head --chain "$OUTPUT_DIR/asset-hub-plain.json" 2>/dev/null > "$TEMP_DIR/asset-hub-head.txt"
+$TEYRCHAIN_BIN export-genesis-wasm --chain "$OUTPUT_DIR/asset-hub-plain.json" 2>/dev/null > "$TEMP_DIR/asset-hub-wasm.txt"
+$TEYRCHAIN_BIN export-genesis-head --chain "$OUTPUT_DIR/people-plain.json" 2>/dev/null > "$TEMP_DIR/people-head.txt"
+$TEYRCHAIN_BIN export-genesis-wasm --chain "$OUTPUT_DIR/people-plain.json" 2>/dev/null > "$TEMP_DIR/people-wasm.txt"
+
+echo "  Asset Hub head: $(head -c 50 $TEMP_DIR/asset-hub-head.txt)..."
+echo "  Asset Hub wasm: $(wc -c < $TEMP_DIR/asset-hub-wasm.txt) bytes"
+echo "  People head: $(head -c 50 $TEMP_DIR/people-head.txt)..."
+echo "  People wasm: $(wc -c < $TEMP_DIR/people-wasm.txt) bytes"
+
+# Add paras to relay chain spec using Python (reading from files)
+python3 << PYEOF
+import json
+
+# Read genesis data from files
+with open("$TEMP_DIR/asset-hub-head.txt", "r") as f:
+    asset_hub_head = f.read().strip()
+with open("$TEMP_DIR/asset-hub-wasm.txt", "r") as f:
+    asset_hub_wasm = f.read().strip()
+with open("$TEMP_DIR/people-head.txt", "r") as f:
+    people_head = f.read().strip()
+with open("$TEMP_DIR/people-wasm.txt", "r") as f:
+    people_wasm = f.read().strip()
+
+# Read relay spec
+with open("$OUTPUT_DIR/relay-plain.json", "r") as f:
+    spec = json.load(f)
+
+# Navigate to patch
+patch = spec.get("genesis", {}).get("runtimeGenesis", {}).get("patch", {})
+if not patch:
+    patch = spec.get("genesis", {}).get("runtime", {})
+
+# Ensure num_cores is 2
+if "configuration" in patch:
+    config = patch["configuration"].get("config", {})
+    scheduler = config.get("scheduler_params", {})
+    scheduler["num_cores"] = 2
+    config["scheduler_params"] = scheduler
+    patch["configuration"]["config"] = config
+    print("  num_cores set to 2")
+
+# Add paras (note: field is "teyrchain" not "para_kind" due to serde rename)
+patch["paras"] = {
+    "paras": [
+        [
+            1000,
+            {
+                "genesis_head": asset_hub_head,
+                "validation_code": asset_hub_wasm,
+                "teyrchain": True
+            }
+        ],
+        [
+            1004,
+            {
+                "genesis_head": people_head,
+                "validation_code": people_wasm,
+                "teyrchain": True
+            }
+        ]
+    ]
+}
+print("  Added paras: 1000 (Asset Hub), 1004 (People Chain)")
+
+# Update spec
+if "runtimeGenesis" in spec.get("genesis", {}):
+    spec["genesis"]["runtimeGenesis"]["patch"] = patch
+else:
+    spec["genesis"]["runtime"] = patch
+
+with open("$OUTPUT_DIR/relay-with-paras.json", "w") as f:
+    json.dump(spec, f)
+
+print("  -> relay-with-paras.json created")
+PYEOF
+
+echo -e "${GREEN}  -> Paras added to relay spec${NC}"
+
+# =============================================================================
+# STEP 5: Convert to raw format
+# =============================================================================
+echo -e "${YELLOW}[5/6] Converting to raw format...${NC}"
+
+echo "  Converting relay chain..."
+$PEZKUWI_BIN build-spec \
+    --chain "$OUTPUT_DIR/relay-with-paras.json" \
+    --raw \
+    --disable-default-bootnode \
+    2>/dev/null > "$OUTPUT_DIR/relay-raw.json"
+echo -e "${GREEN}  -> relay-raw.json created${NC}"
+
+echo "  Converting Asset Hub..."
+$TEYRCHAIN_BIN build-spec \
+    --chain "$OUTPUT_DIR/asset-hub-plain.json" \
+    --raw \
+    --disable-default-bootnode \
+    2>/dev/null > "$OUTPUT_DIR/asset-hub-raw.json"
+echo -e "${GREEN}  -> asset-hub-raw.json created${NC}"
+
+echo "  Converting People Chain..."
+$TEYRCHAIN_BIN build-spec \
+    --chain "$OUTPUT_DIR/people-plain.json" \
+    --raw \
+    --disable-default-bootnode \
+    2>/dev/null > "$OUTPUT_DIR/people-raw.json"
+echo -e "${GREEN}  -> people-raw.json created${NC}"
+
+# =============================================================================
+# STEP 6: Verify
+# =============================================================================
+echo -e "${YELLOW}[6/6] Verifying chain specs...${NC}"
+
+python3 << PYEOF
+import json
+import sys
+
+def verify_spec(path, name, expected_id):
+    try:
+        with open(path, 'r') as f:
+            spec = json.load(f)
+
+        actual_id = spec.get("id", "")
+        if actual_id == expected_id:
+            size_mb = len(json.dumps(spec)) / 1024 / 1024
+            print(f"  ✓ {name}: id={actual_id} ({size_mb:.1f} MB)")
+            return True
+        else:
+            print(f"  ✗ {name}: expected id={expected_id}, got {actual_id}")
+            return False
+    except Exception as e:
+        print(f"  ✗ {name}: Failed to load - {e}")
+        return False
+
+ok = True
+ok = verify_spec("$OUTPUT_DIR/relay-raw.json", "Relay Chain", "pezkuwichain_mainnet") and ok
+ok = verify_spec("$OUTPUT_DIR/asset-hub-raw.json", "Asset Hub", "asset-hub-pezkuwichain") and ok
+ok = verify_spec("$OUTPUT_DIR/people-raw.json", "People Chain", "people-pezkuwichain") and ok
+
+if not ok:
+    sys.exit(1)
+PYEOF
+
+# =============================================================================
+# DONE
+# =============================================================================
+echo ""
+echo -e "${GREEN}=== CHAIN SPECS CREATED SUCCESSFULLY ===${NC}"
+echo ""
+echo "Output files:"
+ls -lh "$OUTPUT_DIR"/*.json
+echo ""
+echo "To deploy to VPS:"
+echo "  scp $OUTPUT_DIR/relay-raw.json root@VPS_IP:/root/chainspec/"
+echo "  scp $OUTPUT_DIR/asset-hub-raw.json root@VPS_IP:/root/chainspec/"
+echo "  scp $OUTPUT_DIR/people-raw.json root@VPS_IP:/root/chainspec/"