GOATNetwork · eigmax · Aug 26, 2026 · Aug 26, 2026 · Aug 26, 2026
diff --git a/.env.template b/.env.template
@@ -3,6 +3,10 @@ RUST_LOG=debug
 # required
 ACTOR=Verifier
 
+# optional, positive integer; must be identical on all participating nodes.
+# Applies to newly created graphs only. Existing finalized graphs keep their original verifier slots.
+MIN_REQUIRED_VERIFIER=1
+
 # required
 GOAT_GATEWAY_CONTRACT_ADDRESS=
 
@@ -25,4 +29,4 @@ GOAT_ADDRESS=
 PROTO_NAME=bitvmt3
 
 # setup bootnodes, separate multiple nodes by comma ",".
-BOOTNODES=
+BOOTNODES=
diff --git a/deployment/README.md b/deployment/README.md
@@ -58,6 +58,9 @@ Create a `.env` file and include necessary environment variables:
 | `GOAT_SWAP_EVENT_THE_GRAPH_URL` | The Graph URL for querying Swap events | Optional |
 | `BOOTNODES` | Multiaddr of bootnodes for P2P discovery | Optional |
 | `NODE_NAME` | The name of the node | Optional |
+| `MIN_REQUIRED_VERIFIER` | Positive verifier-slot count for newly created graphs (default: `1`); must be identical on all participating nodes | Optional |
+
+`MIN_REQUIRED_VERIFIER` changes the transaction topology of newly created graphs. It does not add Verifier slots to existing finalized graphs, which continue to use the slots embedded when they were created. Configure the same value on every Operator, Verifier, Committee, Watchtower, and Relayer node before creating new graphs.
 
 ## Roles Deployment
 

diff --git a/deployment/regtest/bitvm-noded/committee_0/.env.committee_0 b/deployment/regtest/bitvm-noded/committee_0/.env.committee_0
@@ -15,6 +15,7 @@ GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 ENABLE_UPDATE_SPV_CONTRACT=true
 
 # the graph config
+MIN_REQUIRED_VERIFIER=1
 GOAT_GATEWAY_CONTRACT_ADDRESS=
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=
 # block number to start filtering events from
@@ -32,4 +33,4 @@ GENESIS_SEQUENCER_COMMIT_TXID=
 
 # libp2p config
 PEER_KEY=
-PROTO_NAME=bitvm_regtest
+PROTO_NAME=bitvm_regtest
diff --git a/deployment/regtest/bitvm-noded/committee_1/.env.committee_1 b/deployment/regtest/bitvm-noded/committee_1/.env.committee_1
@@ -10,6 +10,7 @@ BTC_CHAIN_URL=http://127.0.0.1:3002
 GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 
 # the graph config
+MIN_REQUIRED_VERIFIER=1
 GOAT_GATEWAY_CONTRACT_ADDRESS=
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=
 # block number to start filtering events from
@@ -28,4 +29,4 @@ GENESIS_SEQUENCER_COMMIT_TXID=
 # libp2p config
 PEER_KEY=
 BOOTNODES=/ip4/127.0.0.1/tcp/8444/p2p/12D3KooWKmAQDFCibTTpKTi6Kwk9SmtLGDXhv5fEsc9gr1Vdcu4j
-PROTO_NAME=bitvm_regtest
+PROTO_NAME=bitvm_regtest
diff --git a/deployment/regtest/bitvm-noded/operator_0/.env.operator_0 b/deployment/regtest/bitvm-noded/operator_0/.env.operator_0
@@ -10,6 +10,7 @@ BTC_CHAIN_URL=http://127.0.0.1:3002
 GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 
 # the graph config
+MIN_REQUIRED_VERIFIER=1
 GOAT_GATEWAY_CONTRACT_ADDRESS=
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=
 # block number to start filtering events from
@@ -52,4 +53,4 @@ FGC_COMPACT_OUT_INDICES_PATH=
 SGC_COMPACT_GATES_PATH=
 SGC_COMPACT_OUT_INDICES_PATH=
 
-ENABLE_BABE_SETUP_STATE_CLEANUP=true
+ENABLE_BABE_SETUP_STATE_CLEANUP=true
diff --git a/deployment/regtest/bitvm-noded/verifier_0/.env.verifier_0 b/deployment/regtest/bitvm-noded/verifier_0/.env.verifier_0
@@ -10,6 +10,7 @@ BTC_CHAIN_URL=http://127.0.0.1:3002
 GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 
 # the graph config
+MIN_REQUIRED_VERIFIER=1
 GOAT_GATEWAY_CONTRACT_ADDRESS=
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=
 GOAT_GATEWAY_EVENT_FILTER_FROM=
@@ -47,4 +48,4 @@ FGC_COMPACT_OUT_INDICES_PATH=
 SGC_COMPACT_GATES_PATH=
 SGC_COMPACT_OUT_INDICES_PATH=
 
-ENABLE_BABE_SETUP_STATE_CLEANUP=true
+ENABLE_BABE_SETUP_STATE_CLEANUP=true
diff --git a/deployment/regtest/bitvm-noded/watchtower_0/.env.watchtower_0 b/deployment/regtest/bitvm-noded/watchtower_0/.env.watchtower_0
@@ -11,6 +11,7 @@ GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 GOAT_PROOF_BUILD_URL=
 
 # the graph config
+MIN_REQUIRED_VERIFIER=1
 GOAT_GATEWAY_CONTRACT_ADDRESS=
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=
 GOAT_GATEWAY_EVENT_FILTER_FROM=
@@ -26,4 +27,4 @@ PEER_KEY=
 BOOTNODES=/ip4/127.0.0.1/tcp/8444/p2p/12D3KooWKmAQDFCibTTpKTi6Kwk9SmtLGDXhv5fEsc9gr1Vdcu4j
 PROTO_NAME=bitvm_regtest
 
-GENESIS_SEQUENCER_COMMIT_TXID=
+GENESIS_SEQUENCER_COMMIT_TXID=
diff --git a/deployment/testnet4/bitvm-noded/committee_0/.env.committee_0 b/deployment/testnet4/bitvm-noded/committee_0/.env.committee_0
@@ -15,6 +15,7 @@ GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 ENABLE_UPDATE_SPV_CONTRACT=true
 
 # the graph config
+MIN_REQUIRED_VERIFIER=2
 GOAT_GATEWAY_CONTRACT_ADDRESS=0x60a5b099eE011018DD064F9eBD50d381C37b5e8b
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=https://graph.goat.network/subgraphs/name/bitvmt4_gateway_0x60a5
 GOAT_GATEWAY_EVENT_FILTER_FROM=15908000
@@ -30,4 +31,4 @@ GOAT_PRIVATE_KEY=
 PEER_KEY=
 PROTO_NAME=bitvmt4
 
-GENESIS_SEQUENCER_COMMIT_TXID=c2d816940391da550af23c7924f8d9ecd276cdf6a22a164fc44443f5eba6d4b5
+GENESIS_SEQUENCER_COMMIT_TXID=c2d816940391da550af23c7924f8d9ecd276cdf6a22a164fc44443f5eba6d4b5
diff --git a/deployment/testnet4/bitvm-noded/committee_1/.env.committee_1 b/deployment/testnet4/bitvm-noded/committee_1/.env.committee_1
@@ -10,6 +10,7 @@ BTC_CHAIN_URL=https://mempool.space/testnet4/api
 GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 
 # the graph config
+MIN_REQUIRED_VERIFIER=2
 GOAT_GATEWAY_CONTRACT_ADDRESS=0x60a5b099eE011018DD064F9eBD50d381C37b5e8b
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=https://graph.goat.network/subgraphs/name/bitvmt4_gateway_0x60a5
 GOAT_GATEWAY_EVENT_FILTER_FROM=15908000
@@ -26,4 +27,4 @@ PEER_KEY=
 BOOTNODES=/ip4/16.146.8.146/tcp/8445/p2p/12D3KooWCrPTAmhFdC5DBGgkxZvJi6iuSeiDWKRL87isrt4iMHXv
 PROTO_NAME=bitvmt4
 
-GENESIS_SEQUENCER_COMMIT_TXID=c2d816940391da550af23c7924f8d9ecd276cdf6a22a164fc44443f5eba6d4b5
+GENESIS_SEQUENCER_COMMIT_TXID=c2d816940391da550af23c7924f8d9ecd276cdf6a22a164fc44443f5eba6d4b5
diff --git a/deployment/testnet4/bitvm-noded/operator_0/.env.operator_0 b/deployment/testnet4/bitvm-noded/operator_0/.env.operator_0
@@ -11,6 +11,7 @@ GOAT_PROOF_BUILD_URL=
 GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 
 # the graph config
+MIN_REQUIRED_VERIFIER=2
 GOAT_GATEWAY_CONTRACT_ADDRESS=0x60a5b099eE011018DD064F9eBD50d381C37b5e8b
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=https://graph.goat.network/subgraphs/name/bitvmt4_gateway_0x60a5
 GOAT_GATEWAY_EVENT_FILTER_FROM=15908000
@@ -47,4 +48,4 @@ FGC_COMPACT_OUT_INDICES_PATH=
 SGC_COMPACT_GATES_PATH=
 SGC_COMPACT_OUT_INDICES_PATH=
 
-ENABLE_BABE_SETUP_STATE_CLEANUP=true
+ENABLE_BABE_SETUP_STATE_CLEANUP=true
diff --git a/deployment/testnet4/bitvm-noded/verifier_0/.env.verifier_0 b/deployment/testnet4/bitvm-noded/verifier_0/.env.verifier_0
@@ -10,6 +10,7 @@ BTC_CHAIN_URL=https://mempool.space/testnet4/api
 GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 
 # the graph config
+MIN_REQUIRED_VERIFIER=2
 GOAT_GATEWAY_CONTRACT_ADDRESS=0x60a5b099eE011018DD064F9eBD50d381C37b5e8b
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=https://graph.goat.network/subgraphs/name/bitvmt4_gateway_0x60a5
 GOAT_GATEWAY_EVENT_FILTER_FROM=15908000
@@ -48,4 +49,4 @@ FGC_COMPACT_OUT_INDICES_PATH=
 SGC_COMPACT_GATES_PATH=
 SGC_COMPACT_OUT_INDICES_PATH=
 
-ENABLE_BABE_SETUP_STATE_CLEANUP=true
+ENABLE_BABE_SETUP_STATE_CLEANUP=true
diff --git a/deployment/testnet4/bitvm-noded/watchtower_0/.env.watchtower_0 b/deployment/testnet4/bitvm-noded/watchtower_0/.env.watchtower_0
@@ -11,6 +11,7 @@ GOAT_CHAIN_URL=https://rpc.testnet3.goat.network
 GOAT_PROOF_BUILD_URL=
 
 # the graph config
+MIN_REQUIRED_VERIFIER=2
 GOAT_GATEWAY_CONTRACT_ADDRESS=0x60a5b099eE011018DD064F9eBD50d381C37b5e8b
 GOAT_GATEWAY_EVENT_THE_GRAPH_URL=https://graph.goat.network/subgraphs/name/bitvmt4_gateway_0x60a5
 GOAT_GATEWAY_EVENT_FILTER_FROM=15908000
@@ -26,4 +27,4 @@ PEER_KEY=
 BOOTNODES=/ip4/16.146.8.146/tcp/8445/p2p/12D3KooWCrPTAmhFdC5DBGgkxZvJi6iuSeiDWKRL87isrt4iMHXv
 PROTO_NAME=bitvmt4
 
-GENESIS_SEQUENCER_COMMIT_TXID=c2d816940391da550af23c7924f8d9ecd276cdf6a22a164fc44443f5eba6d4b5
+GENESIS_SEQUENCER_COMMIT_TXID=c2d816940391da550af23c7924f8d9ecd276cdf6a22a164fc44443f5eba6d4b5
diff --git a/node/src/env.rs b/node/src/env.rs
@@ -60,6 +60,7 @@ pub const ENV_PROOF_SEVER_URL: &str = "PROOF_SEVER_URL";
 pub const ENV_ACTOR: &str = "ACTOR";
 pub const ENV_IPFS_ENDPOINT: &str = "IPFS_ENDPOINT";
 pub const ENV_COMMITTEE_NUM: &str = "COMMITTEE_NUM";
+pub const ENV_MIN_REQUIRED_VERIFIER: &str = "MIN_REQUIRED_VERIFIER";
 pub const ENV_EXTERNAL_SOCKET_ADDR: &str = "EXTERNAL_SOCKET_ADDR";
 pub const COMMITTEE_INSTANCE_KEYS_DIR: &str = "cache/committee-instance-keys/";
 pub const SCRIPT_CACHE_FILE_NAME: &str = "cache/partial_script.bin";
@@ -69,6 +70,7 @@ pub const DUST_AMOUNT: u64 = goat::transactions::base::DUST_AMOUNT;
 pub const MAX_CUSTOM_INPUTS: usize = 100;
 
 pub const DEFAULT_CONFIRMATION_TARGET: u16 = 1;
+pub const DEFAULT_MIN_REQUIRED_VERIFIER: usize = 1;
 
 pub const ENV_BITCOIN_NETWORK: &str = "BITCOIN_NETWORK";
 pub const ENV_GOAT_NETWORK: &str = "GOAT_NETWORK";
@@ -577,6 +579,16 @@ pub fn get_operator_proof_wait_secs() -> usize {
         .unwrap_or(DEFAULT_OPERATOR_PROOF_WAIT_SECS)
 }
 
+pub fn get_min_required_verifier() -> anyhow::Result<usize> {
+    match std::env::var(ENV_MIN_REQUIRED_VERIFIER) {
+        Err(std::env::VarError::NotPresent) => Ok(DEFAULT_MIN_REQUIRED_VERIFIER),
+        Err(error) => Err(anyhow::anyhow!("failed to read {ENV_MIN_REQUIRED_VERIFIER}: {error}")),
+        Ok(value) => value.parse::<usize>().ok().filter(|value| *value > 0).ok_or_else(|| {
+            anyhow::anyhow!("{ENV_MIN_REQUIRED_VERIFIER} must be a positive integer, got {value:?}")
+        }),
+    }
+}
+
 pub fn get_soldering_proof_payload_store_path() -> anyhow::Result<String> {
     let value = std::env::var(ENV_SOLDERING_PROOF_PAYLOAD_STORE_PATH)
         .map_err(|_| anyhow::anyhow!("{ENV_SOLDERING_PROOF_PAYLOAD_STORE_PATH} needs to be set"))?;