diff --git a/crates/cli/src/app_builder.rs b/crates/cli/src/app_builder.rs
index 3fd3866ec..8a12bbdcf 100644
--- a/crates/cli/src/app_builder.rs
+++ b/crates/cli/src/app_builder.rs
@@ -109,7 +109,7 @@ pub trait AppBuilder: CommandBuilder {
 
         match top_matches.subcommand() {
             Some(("setup", _)) => match host_mode {
-                HostMode::DEFAULT => exec_setup::<ExecutionArg, DefaultHostEnvBuilder>(
+                HostMode::DEFAULT => exec_setup::<DefaultHostEnvBuilder>(
                     zkwasm_k,
                     Self::AGGREGATE_K,
                     Self::NAME,
@@ -119,7 +119,7 @@ pub trait AppBuilder: CommandBuilder {
                     &output_dir,
                     &param_dir,
                 ),
-                HostMode::STANDARD => exec_setup::<StandardArg, StandardEnvBuilder>(
+                HostMode::STANDARD => exec_setup::<StandardEnvBuilder>(
                     zkwasm_k,
                     Self::AGGREGATE_K,
                     Self::NAME,
@@ -132,14 +132,14 @@ pub trait AppBuilder: CommandBuilder {
             },
 
             Some(("checksum", _)) => match host_mode {
-                HostMode::DEFAULT => exec_image_checksum::<ExecutionArg, DefaultHostEnvBuilder>(
+                HostMode::DEFAULT => exec_image_checksum::<DefaultHostEnvBuilder>(
                     zkwasm_k,
                     wasm_binary,
                     (),
                     phantom_functions,
                     &output_dir,
                 ),
-                HostMode::STANDARD => exec_image_checksum::<StandardArg, StandardEnvBuilder>(
+                HostMode::STANDARD => exec_image_checksum::<StandardEnvBuilder>(
                     zkwasm_k,
                     wasm_binary,
                     HostEnvConfig::default(),
@@ -160,7 +160,7 @@ pub trait AppBuilder: CommandBuilder {
 
                 match host_mode {
                     HostMode::DEFAULT => {
-                        exec_dry_run::<ExecutionArg, DefaultHostEnvBuilder>(
+                        exec_dry_run::<DefaultHostEnvBuilder>(
                             zkwasm_k,
                             wasm_binary,
                             phantom_functions,
@@ -174,7 +174,7 @@ pub trait AppBuilder: CommandBuilder {
                         )?;
                     }
                     HostMode::STANDARD => {
-                        exec_dry_run::<StandardArg, StandardEnvBuilder>(
+                        exec_dry_run::<StandardEnvBuilder>(
                             zkwasm_k,
                             wasm_binary,
                             phantom_functions,
@@ -206,7 +206,7 @@ pub trait AppBuilder: CommandBuilder {
                 assert!(public_inputs.len() <= Self::MAX_PUBLIC_INPUT_SIZE);
                 match host_mode {
                     HostMode::DEFAULT => {
-                        exec_create_proof::<ExecutionArg, DefaultHostEnvBuilder>(
+                        exec_create_proof::<DefaultHostEnvBuilder>(
                             Self::NAME,
                             zkwasm_k,
                             wasm_binary,
@@ -223,7 +223,7 @@ pub trait AppBuilder: CommandBuilder {
                         )?;
                     }
                     HostMode::STANDARD => {
-                        exec_create_proof::<StandardArg, StandardEnvBuilder>(
+                        exec_create_proof::<StandardEnvBuilder>(
                             Self::NAME,
                             zkwasm_k,
                             wasm_binary,
diff --git a/crates/cli/src/args.rs b/crates/cli/src/args.rs
index 334645980..39b7e1985 100644
--- a/crates/cli/src/args.rs
+++ b/crates/cli/src/args.rs
@@ -51,11 +51,13 @@ pub trait ArgBuilder {
     }
 
     fn host_mode_arg<'a>() -> Arg<'a> {
-        arg!(
-            -h --host <HOST_MODE> "Which host env you would like to run your binary."
-        )
-        .max_values(1)
-        .value_parser(value_parser!(HostMode))
+        Arg::new("host")
+            .long("host")
+            .value_parser(value_parser!(HostMode))
+            .action(ArgAction::Set)
+            .help("Specify host functions set.")
+            .min_values(0)
+            .max_values(1)
     }
 
     fn parse_host_mode(matches: &ArgMatches) -> HostMode {
diff --git a/crates/cli/src/exec.rs b/crates/cli/src/exec.rs
index 6fcbefdb6..a6721f745 100644
--- a/crates/cli/src/exec.rs
+++ b/crates/cli/src/exec.rs
@@ -17,7 +17,7 @@ use log::info;
 use std::io::Write;
 use std::path::PathBuf;
 
-pub fn exec_setup<Arg, Builder>(
+pub fn exec_setup<Builder: HostEnvBuilder>(
     zkwasm_k: u32,
     aggregate_k: u32,
     prefix: &str,
@@ -26,10 +26,7 @@ pub fn exec_setup<Arg, Builder>(
     envconfig: Builder::HostConfig,
     _output_dir: &PathBuf,
     param_dir: &PathBuf,
-) -> Result<()>
-where
-    Builder: HostEnvBuilder<Arg = Arg>,
-{
+) -> Result<()> {
     info!("Setup Params and VerifyingKey");
 
     macro_rules! prepare_params {
@@ -57,8 +54,11 @@ where
             info!("Found Verifying at {:?}", vk_path);
         } else {
             info!("Create Verifying to {:?}", vk_path);
-            let loader =
-                ZkWasmLoader::<Bn256, Arg, Builder>::new(zkwasm_k, wasm_binary, phantom_functions)?;
+            let loader = ZkWasmLoader::<Bn256, Builder::Arg, Builder>::new(
+                zkwasm_k,
+                wasm_binary,
+                phantom_functions,
+            )?;
 
             let vkey = loader.create_vkey(&params, envconfig)?;
 
@@ -70,7 +70,7 @@ where
     Ok(())
 }
 
-pub fn exec_image_checksum<Arg, Builder>(
+pub fn exec_image_checksum<Builder>(
     zkwasm_k: u32,
     wasm_binary: Vec<u8>,
     hostenv: Builder::HostConfig,
@@ -78,10 +78,13 @@ pub fn exec_image_checksum<Arg, Builder>(
     output_dir: &PathBuf,
 ) -> Result<()>
 where
-    Builder: HostEnvBuilder<Arg = Arg>,
+    Builder: HostEnvBuilder,
 {
-    let loader =
-        ZkWasmLoader::<Bn256, Arg, Builder>::new(zkwasm_k, wasm_binary, phantom_functions)?;
+    let loader = ZkWasmLoader::<Bn256, Builder::Arg, Builder>::new(
+        zkwasm_k,
+        wasm_binary,
+        phantom_functions,
+    )?;
 
     let params = load_or_build_unsafe_params::<Bn256>(
         zkwasm_k,
@@ -102,33 +105,39 @@ where
     Ok(())
 }
 
-pub fn exec_dry_run<Arg, Builder: HostEnvBuilder<Arg = Arg>>(
+pub fn exec_dry_run<Builder: HostEnvBuilder>(
     zkwasm_k: u32,
     wasm_binary: Vec<u8>,
     phantom_functions: Vec<String>,
-    arg: Arg,
+    arg: Builder::Arg,
     config: Builder::HostConfig,
 ) -> Result<()> {
-    let loader =
-        ZkWasmLoader::<Bn256, Arg, Builder>::new(zkwasm_k, wasm_binary, phantom_functions)?;
+    let loader = ZkWasmLoader::<Bn256, Builder::Arg, Builder>::new(
+        zkwasm_k,
+        wasm_binary,
+        phantom_functions,
+    )?;
     let result = loader.run(arg, config, true, false)?;
     println!("total guest instructions used {:?}", result.guest_statics);
     println!("total host api used {:?}", result.host_statics);
     Ok(())
 }
 
-pub fn exec_create_proof<Arg, Builder: HostEnvBuilder<Arg = Arg>>(
+pub fn exec_create_proof<Builder: HostEnvBuilder>(
     prefix: &'static str,
     zkwasm_k: u32,
     wasm_binary: Vec<u8>,
     phantom_functions: Vec<String>,
     output_dir: &PathBuf,
     param_dir: &PathBuf,
-    arg: Arg,
+    arg: Builder::Arg,
     config: Builder::HostConfig,
 ) -> Result<()> {
-    let loader =
-        ZkWasmLoader::<Bn256, Arg, Builder>::new(zkwasm_k, wasm_binary, phantom_functions)?;
+    let loader = ZkWasmLoader::<Bn256, Builder::Arg, Builder>::new(
+        zkwasm_k,
+        wasm_binary,
+        phantom_functions,
+    )?;
 
     let execution_result = loader.run(arg, config, false, true)?;