diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9dd9043c0c..ab402d7386 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -63,6 +63,11 @@ Note that the default value of `allow_raw_access` is still `true`.
 Removed the logic for calling a different version of dfx based on DFX_VERSION or the `dfx` field in
 dfx.json.  This is now performed by dfxvm.
 
+### feat: --always-assist flag for `dfx canister call/install/sign and dfx deploy`
+
+When all the arguments are optional, dfx automatically provides a `null` value when no arguments are provided.
+`--always-assist` flag enables the candid assist feature for optional arguments, instead of providing a default `null` value.
+
 ## Dependencies
 
 ### Replica
diff --git a/src/dfx/src/commands/canister/call.rs b/src/dfx/src/commands/canister/call.rs
index 400291a8e6..6ec0d2b336 100644
--- a/src/dfx/src/commands/canister/call.rs
+++ b/src/dfx/src/commands/canister/call.rs
@@ -51,7 +51,12 @@ pub struct CanisterCallOpts {
     update: bool,
 
     /// Specifies the config for generating random argument.
-    #[arg(long, conflicts_with("argument"), conflicts_with("argument_file"))]
+    #[arg(
+        long,
+        conflicts_with("argument"),
+        conflicts_with("argument_file"),
+        conflicts_with("always_assist")
+    )]
     random: Option<String>,
 
     /// Specifies the format for displaying the method's return result.
@@ -69,6 +74,15 @@ pub struct CanisterCallOpts {
     /// for project canisters.
     #[arg(long)]
     candid: Option<PathBuf>,
+
+    /// Always use Candid assist when the argument types are all optional.
+    #[arg(
+        long,
+        conflicts_with("argument"),
+        conflicts_with("argument_file"),
+        conflicts_with("random")
+    )]
+    always_assist: bool,
 }
 
 #[derive(Clone, CandidType, Deserialize, Debug)]
@@ -282,6 +296,7 @@ pub async fn exec(
         argument_type.as_deref(),
         &method_type,
         false,
+        opts.always_assist,
     )?;
 
     // amount has been validated by cycle_amount_validator
diff --git a/src/dfx/src/commands/canister/delete.rs b/src/dfx/src/commands/canister/delete.rs
index e2341a8cb0..43db297d6c 100644
--- a/src/dfx/src/commands/canister/delete.rs
+++ b/src/dfx/src/commands/canister/delete.rs
@@ -199,7 +199,7 @@ async fn delete_canister(
                 "Installing temporary wallet in canister {} to enable transfer of cycles.",
                 canister
             );
-            let args = blob_from_arguments(None, None, None, None, &None, false)?;
+            let args = blob_from_arguments(None, None, None, None, &None, false, false)?;
             let mode = InstallMode::Reinstall;
             let install_builder = mgr
                 .install_code(&canister_id, &wasm_module)
diff --git a/src/dfx/src/commands/canister/install.rs b/src/dfx/src/commands/canister/install.rs
index dff780db7c..fbaeda35b6 100644
--- a/src/dfx/src/commands/canister/install.rs
+++ b/src/dfx/src/commands/canister/install.rs
@@ -64,6 +64,15 @@ pub struct CanisterInstallOpts {
     /// Skips upgrading the asset canister, to only install the assets themselves.
     #[arg(long)]
     no_asset_upgrade: bool,
+
+    /// Always use Candid assist when the argument types are all optional.
+    #[arg(
+        long,
+        conflicts_with("argument"),
+        conflicts_with("argument_file"),
+        conflicts_with("yes")
+    )]
+    always_assist: bool,
 }
 
 pub async fn exec(
@@ -97,6 +106,7 @@ pub async fn exec(
                     argument_type.as_deref(),
                     &None,
                     true,
+                    opts.always_assist,
                 )?;
                 let wasm_module = dfx_core::fs::read(wasm_path)?;
                 let mode = mode.context("The install mode cannot be auto when using --wasm")?;
@@ -157,6 +167,7 @@ pub async fn exec(
                     opts.yes,
                     None,
                     opts.no_asset_upgrade,
+                    opts.always_assist,
                 )
                 .await
                 .map_err(Into::into)
@@ -176,6 +187,7 @@ pub async fn exec(
                     opts.yes,
                     env_file.as_deref(),
                     opts.no_asset_upgrade,
+                    opts.always_assist,
                 )
                 .await
                 .map_err(Into::into)
@@ -219,6 +231,7 @@ pub async fn exec(
                     opts.yes,
                     env_file.as_deref(),
                     opts.no_asset_upgrade,
+                    opts.always_assist,
                 )
                 .await?;
             }
diff --git a/src/dfx/src/commands/canister/sign.rs b/src/dfx/src/commands/canister/sign.rs
index 1356c1b427..0a1051ae79 100644
--- a/src/dfx/src/commands/canister/sign.rs
+++ b/src/dfx/src/commands/canister/sign.rs
@@ -43,7 +43,12 @@ pub struct CanisterSignOpts {
     update: bool,
 
     /// Specifies the config for generating random argument.
-    #[arg(long, conflicts_with("argument"), conflicts_with("argument_file"))]
+    #[arg(
+        long,
+        conflicts_with("argument"),
+        conflicts_with("argument_file"),
+        conflicts_with("always_assist")
+    )]
     random: Option<String>,
 
     /// Specifies how long the message will be valid in seconds, default to be 300s (5 minutes)
@@ -53,6 +58,15 @@ pub struct CanisterSignOpts {
     /// Specifies the output file name.
     #[arg(long, default_value = "message.json")]
     file: PathBuf,
+
+    /// Always use Candid assist when the argument types are all optional.
+    #[arg(
+        long,
+        conflicts_with("argument"),
+        conflicts_with("argument_file"),
+        conflicts_with("random")
+    )]
+    always_assist: bool,
 }
 
 pub async fn exec(
@@ -99,6 +113,7 @@ pub async fn exec(
         argument_type.as_deref(),
         &method_type,
         false,
+        opts.always_assist,
     )?;
     let agent = env.get_agent();
 
diff --git a/src/dfx/src/commands/deploy.rs b/src/dfx/src/commands/deploy.rs
index 96f463e3d8..ea9ddff556 100644
--- a/src/dfx/src/commands/deploy.rs
+++ b/src/dfx/src/commands/deploy.rs
@@ -113,6 +113,15 @@ pub struct DeployOpts {
 
     #[command(flatten)]
     subnet_selection: SubnetSelectionOpt,
+
+    /// Always use Candid assist when the argument types are all optional.
+    #[arg(
+        long,
+        conflicts_with("argument"),
+        conflicts_with("argument_file"),
+        conflicts_with("yes")
+    )]
+    always_assist: bool,
 }
 
 pub fn exec(env: &dyn Environment, opts: DeployOpts) -> DfxResult {
@@ -192,6 +201,7 @@ pub fn exec(env: &dyn Environment, opts: DeployOpts) -> DfxResult {
         env_file,
         opts.no_asset_upgrade,
         &mut subnet_selection,
+        opts.always_assist,
     ))?;
 
     if matches!(deploy_mode, NormalDeploy | ForceReinstallSingleCanister(_)) {
diff --git a/src/dfx/src/lib/integrations/mod.rs b/src/dfx/src/lib/integrations/mod.rs
index ee35e4062d..0edc4c77ae 100644
--- a/src/dfx/src/lib/integrations/mod.rs
+++ b/src/dfx/src/lib/integrations/mod.rs
@@ -49,7 +49,7 @@ pub async fn initialize_integration_canister(
     };
     try_create_canister(agent, logger, &canister_id, &pulled_canister).await?;
 
-    let install_arg = blob_from_arguments(None, Some(init_arg), None, None, &None, true)?;
+    let install_arg = blob_from_arguments(None, Some(init_arg), None, None, &None, true, false)?;
     install_canister(agent, logger, &canister_id, wasm, install_arg, name).await
 }
 
diff --git a/src/dfx/src/lib/operations/canister/deploy_canisters.rs b/src/dfx/src/lib/operations/canister/deploy_canisters.rs
index 3bacf81cd2..a50da48962 100644
--- a/src/dfx/src/lib/operations/canister/deploy_canisters.rs
+++ b/src/dfx/src/lib/operations/canister/deploy_canisters.rs
@@ -38,6 +38,7 @@ pub enum DeployMode {
 }
 
 #[context("Failed while trying to deploy canisters.")]
+#[allow(clippy::too_many_arguments)]
 pub async fn deploy_canisters(
     env: &dyn Environment,
     some_canister: Option<&str>,
@@ -55,6 +56,7 @@ pub async fn deploy_canisters(
     env_file: Option<PathBuf>,
     no_asset_upgrade: bool,
     subnet_selection: &mut SubnetSelectionType,
+    always_assist: bool,
 ) -> DfxResult {
     let log = env.get_logger();
 
@@ -156,6 +158,7 @@ pub async fn deploy_canisters(
                 skip_consent,
                 env_file.as_deref(),
                 no_asset_upgrade,
+                always_assist,
             )
             .await?;
             info!(log, "Deployed canisters.");
@@ -307,6 +310,7 @@ async fn install_canisters(
     skip_consent: bool,
     env_file: Option<&Path>,
     no_asset_upgrade: bool,
+    always_assist: bool,
 ) -> DfxResult {
     info!(env.get_logger(), "Installing canisters...");
 
@@ -340,6 +344,7 @@ async fn install_canisters(
             skip_consent,
             env_file,
             no_asset_upgrade,
+            always_assist,
         )
         .await?;
     }
diff --git a/src/dfx/src/lib/operations/canister/install_canister.rs b/src/dfx/src/lib/operations/canister/install_canister.rs
index 489990981d..f37a415c66 100644
--- a/src/dfx/src/lib/operations/canister/install_canister.rs
+++ b/src/dfx/src/lib/operations/canister/install_canister.rs
@@ -50,6 +50,7 @@ pub async fn install_canister(
     skip_consent: bool,
     env_file: Option<&Path>,
     no_asset_upgrade: bool,
+    always_assist: bool,
 ) -> DfxResult {
     let log = env.get_logger();
     let agent = env.get_agent();
@@ -165,8 +166,15 @@ The command line value will be used.",
             (None, Some(_)) => (argument_from_json, Some("idl")), // `init_arg` in dfx.json is always in Candid format
             (None, None) => (None, None),
         };
-        let install_args =
-            blob_from_arguments(Some(env), argument, None, argument_type, &init_type, true)?;
+        let install_args = blob_from_arguments(
+            Some(env),
+            argument,
+            None,
+            argument_type,
+            &init_type,
+            true,
+            always_assist,
+        )?;
         if let Some(timestamp) = canister_id_store.get_timestamp(canister_info.get_name()) {
             let new_timestamp = playground_install_code(
                 env,
diff --git a/src/dfx/src/util/mod.rs b/src/dfx/src/util/mod.rs
index 6657144f4a..9defe3d3b9 100644
--- a/src/dfx/src/util/mod.rs
+++ b/src/dfx/src/util/mod.rs
@@ -197,6 +197,7 @@ pub fn blob_from_arguments(
     arg_type: Option<&str>,
     method_type: &Option<(TypeEnv, Function)>,
     is_init_arg: bool,
+    always_assist: bool,
 ) -> DfxResult<Vec<u8>> {
     let arg_type = arg_type.unwrap_or("idl");
     match arg_type {
@@ -226,6 +227,7 @@ pub fn blob_from_arguments(
                         .args
                         .iter()
                         .all(|t| matches!(t.as_ref(), TypeInner::Opt(_)))
+                        && !always_assist
                     {
                         // If the user provided no arguments, and if all the expected arguments are
                         // optional, then use null values.