diff --git a/tools/deploy-optimizer.sh b/tools/deploy-optimizer.sh
index b27350b..b6504e7 100755
--- a/tools/deploy-optimizer.sh
+++ b/tools/deploy-optimizer.sh
@@ -15,6 +15,11 @@
 #   OPTIMIZER_PROXY   Address of the deployed UUPS proxy to upgrade.
 #   RPC_URL           JSON-RPC endpoint.
 #   SECRET_FILE       Path to seed-phrase file (default: onchain/.secret).
+#
+# Environment (dry-run mode only):
+#   ANVIL_FORK_URL    Required when Anvil is not already running.  Must point to
+#                     a Base RPC endpoint so that forked state includes Uniswap V3
+#                     Factory and WETH.
 # =============================================================================
 
 set -euo pipefail
@@ -176,12 +181,29 @@ else
     fi
     SECRET_FILE="$ONCHAIN_DIR/.secret"
 
-    # Check if Anvil is already running
+    # Check if Anvil is already running.
+    #
+    # DeployLocal.sol depends on live Base infrastructure: Uniswap V3 Factory at
+    # 0x4752ba5DBc23f44D87826276BF6Fd6b1C372aD24 and WETH at
+    # 0x4200000000000000000000000000000000000006.  A plain (unfork'd) Anvil has
+    # neither, so cold-starting without --fork-url silently breaks the pipeline.
+    #
+    # When Anvil is already running (dev stack or CI), we use it as-is.
+    # When it is not running we require ANVIL_FORK_URL and start a forked instance.
     if cast chain-id --rpc-url "$RPC_URL" >/dev/null 2>&1; then
         info "Anvil already running at $RPC_URL"
     else
-        info "Starting Anvil..."
+        ANVIL_FORK_URL="${ANVIL_FORK_URL:-}"
+        if [ -z "$ANVIL_FORK_URL" ]; then
+            fail "Anvil is not running at $RPC_URL and ANVIL_FORK_URL is not set.
+  DeployLocal.sol requires Base network contracts (Uniswap V3 Factory, WETH).
+  Either start a Base-forked Anvil externally, or set ANVIL_FORK_URL to a Base
+  RPC endpoint (e.g. ANVIL_FORK_URL=https://mainnet.base.org)."
+        fi
+
+        info "Starting Anvil (fork: $ANVIL_FORK_URL)..."
         anvil --silent \
+              --fork-url "$ANVIL_FORK_URL" \
               --mnemonic "test test test test test test test test test test test junk" \
               --port 8545 &
         ANVIL_PID=$!
@@ -192,7 +214,7 @@ else
             [ $TRIES -gt 50 ] && fail "Anvil did not start within 50 attempts"
             sleep 0.2
         done
-        info "Anvil started (PID $ANVIL_PID)"
+        info "Anvil started (PID $ANVIL_PID, fork: $ANVIL_FORK_URL)"
     fi
 
     # If no OPTIMIZER_PROXY set, deploy a fresh local stack