diff --git a/STATE.md b/STATE.md
index d2eb0d0..b376674 100644
--- a/STATE.md
+++ b/STATE.md
@@ -32,3 +32,4 @@
 - [2026-03-14] batch-eval.sh MANIFEST_DIR (mktemp -d) has no cleanup trap (#763)
 - [2026-03-14] bootstrap.sh anvil_setCode guard now targets correct feeDest 0xf6a3... (#760)
 - [2026-03-14] llm_contrarian.push3 AW=150/250 clamped to 100 — three rounds unaddressed (#756)
+- [2026-03-14] bootstrap.sh hardcodes BASE_SEPOLIA_LOCAL_FORK even on mainnet forks (#746)
diff --git a/containers/bootstrap.sh b/containers/bootstrap.sh
index fc18ba9..1952593 100755
--- a/containers/bootstrap.sh
+++ b/containers/bootstrap.sh
@@ -38,6 +38,24 @@ mkdir -p "$LOG_DIR"
 # ── Configure shared bootstrap variables ──
 ANVIL_RPC=${ANVIL_RPC:-"http://anvil:8545"}
 CONTRACT_ENV=$STATE_DIR/contracts.env
+
+# Derive NETWORK_NAME from FORK_URL if not explicitly set.
+# Callers may override by exporting NETWORK_NAME before starting the stack.
+# Chain ID 8453 = Base mainnet; anything else (including 84532 Base Sepolia) defaults to Sepolia fork.
+if [[ -z "${NETWORK_NAME:-}" ]]; then
+  _fork_url="${FORK_URL:-}"
+  if [[ -n "$_fork_url" ]]; then
+    _chain_id=$(cast chain-id --rpc-url "$_fork_url" 2>/dev/null || echo "")
+    if [[ "$_chain_id" == "8453" ]]; then
+      NETWORK_NAME="BASE_MAINNET_LOCAL_FORK"
+    else
+      NETWORK_NAME="BASE_SEPOLIA_LOCAL_FORK"
+    fi
+  else
+    NETWORK_NAME="BASE_SEPOLIA_LOCAL_FORK"
+  fi
+fi
+
 LOG_FILE=$SETUP_LOG
 ONCHAIN_DIR=$ROOT_DIR/onchain
 TXNBOT_FUND_VALUE=${TXNBOT_FUND_VALUE:-1ether}
@@ -83,11 +101,11 @@ derive_txnbot_wallet() {
 
 write_ponder_env() {
   cat >"$ROOT_DIR/services/ponder/.env.local" <<EOPONDER
-PONDER_NETWORK=BASE_SEPOLIA_LOCAL_FORK
+PONDER_NETWORK=$NETWORK_NAME
 KRAIKEN_ADDRESS=$KRAIKEN
 STAKE_ADDRESS=$STAKE
 START_BLOCK=$DEPLOY_BLOCK
-PONDER_RPC_URL_BASE_SEPOLIA_LOCAL_FORK=$ANVIL_RPC
+PONDER_RPC_URL_${NETWORK_NAME}=$ANVIL_RPC
 DATABASE_URL=postgresql://ponder:ponder_local@postgres:5432/ponder_local
 DATABASE_SCHEMA=ponder_local_${DEPLOY_BLOCK}
 EOPONDER
@@ -98,7 +116,7 @@ write_txn_bot_env() {
   local provider_url=${TXNBOT_PROVIDER_URL:-$ANVIL_RPC}
   local graphql_endpoint=${TXNBOT_GRAPHQL_ENDPOINT:-http://ponder:42069/graphql}
   cat >"$txnbot_env" <<EOTXNBOT
-ENVIRONMENT=BASE_SEPOLIA_LOCAL_FORK
+ENVIRONMENT=$NETWORK_NAME
 PROVIDER_URL=$provider_url
 PRIVATE_KEY=$TXNBOT_PRIVATE_KEY
 LM_CONTRACT_ADDRESS=$LIQUIDITY_MANAGER
diff --git a/services/ponder/ponder.config.ts b/services/ponder/ponder.config.ts
index 03a90a9..37cd93d 100644
--- a/services/ponder/ponder.config.ts
+++ b/services/ponder/ponder.config.ts
@@ -27,6 +27,17 @@ const networks: Record<string, NetworkConfig> = {
       startBlock: parseInt(process.env.START_BLOCK || '31425917'),
     },
   },
+  BASE_MAINNET_LOCAL_FORK: {
+    chainId: 31337,
+    rpc: process.env.PONDER_RPC_URL_BASE_MAINNET_LOCAL_FORK || 'http://127.0.0.1:8545',
+    disableCache: true,
+    contracts: {
+      kraiken: process.env.KRAIKEN_ADDRESS || '0x45caa5929f6ee038039984205bdecf968b954820',
+      stake: process.env.STAKE_ADDRESS || '0xed70707fab05d973ad41eae8d17e2bcd36192cfc',
+      liquidityManager: process.env.LM_ADDRESS || '0x0000000000000000000000000000000000000000',
+      startBlock: parseInt(process.env.START_BLOCK || '26038614'),
+    },
+  },
   BASE_SEPOLIA: {
     chainId: 84532,
     rpc: process.env.PONDER_RPC_URL_BASE_SEPOLIA || 'https://sepolia.base.org',