diff --git a/app/Jobs/ApplicationDeploymentJob.php b/app/Jobs/ApplicationDeploymentJob.php
index 503366e5d..297585562 100644
--- a/app/Jobs/ApplicationDeploymentJob.php
+++ b/app/Jobs/ApplicationDeploymentJob.php
@@ -41,7 +41,7 @@ class ApplicationDeploymentJob implements ShouldBeEncrypted, ShouldQueue
 {
     use Dispatchable, EnvironmentVariableAnalyzer, ExecuteRemoteCommand, InteractsWithQueue, Queueable, SerializesModels;
 
-    private const BUILD_TIME_ENV_PATH = '/artifacts/build-time.env';
+    public const BUILD_TIME_ENV_PATH = '/artifacts/build-time.env';
 
     private const BUILD_SCRIPT_PATH = '/artifacts/build.sh';
 
diff --git a/app/Livewire/Project/Application/General.php b/app/Livewire/Project/Application/General.php
index 5817d2883..71ca9720e 100644
--- a/app/Livewire/Project/Application/General.php
+++ b/app/Livewire/Project/Application/General.php
@@ -1012,12 +1012,16 @@ public function getDockerComposeBuildCommandPreviewProperty(): string
             return '';
         }
 
+        // Normalize baseDirectory to prevent double slashes (e.g., when baseDirectory is '/')
+        $normalizedBase = $this->baseDirectory === '/' ? '' : rtrim($this->baseDirectory, '/');
+
         // Use relative path for clarity in preview (e.g., ./backend/docker-compose.yaml)
         // Actual deployment uses absolute path: /artifacts/{deployment_uuid}{base_directory}{docker_compose_location}
+        // Build-time env path references ApplicationDeploymentJob::BUILD_TIME_ENV_PATH as source of truth
         return injectDockerComposeFlags(
             $this->dockerComposeCustomBuildCommand,
-            ".{$this->baseDirectory}{$this->dockerComposeLocation}",
-            '/artifacts/build-time.env'
+            ".{$normalizedBase}{$this->dockerComposeLocation}",
+            \App\Jobs\ApplicationDeploymentJob::BUILD_TIME_ENV_PATH
         );
     }
 
@@ -1027,11 +1031,14 @@ public function getDockerComposeStartCommandPreviewProperty(): string
             return '';
         }
 
+        // Normalize baseDirectory to prevent double slashes (e.g., when baseDirectory is '/')
+        $normalizedBase = $this->baseDirectory === '/' ? '' : rtrim($this->baseDirectory, '/');
+
         // Use relative path for clarity in preview (e.g., ./backend/docker-compose.yaml)
         // Placeholder {workdir}/.env shows it's the workdir .env file (runtime env, not build-time)
         return injectDockerComposeFlags(
             $this->dockerComposeCustomStartCommand,
-            ".{$this->baseDirectory}{$this->dockerComposeLocation}",
+            ".{$normalizedBase}{$this->dockerComposeLocation}",
             '{workdir}/.env'
         );
     }
diff --git a/tests/Unit/Livewire/ApplicationGeneralPreviewTest.php b/tests/Unit/Livewire/ApplicationGeneralPreviewTest.php
new file mode 100644
index 000000000..cea05a998
--- /dev/null
+++ b/tests/Unit/Livewire/ApplicationGeneralPreviewTest.php
@@ -0,0 +1,156 @@
+<?php
+
+use App\Jobs\ApplicationDeploymentJob;
+use App\Livewire\Project\Application\General;
+
+it('prevents double slashes in build command preview when baseDirectory is root', function () {
+    // Mock the component with properties
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomBuildCommand = 'docker compose build';
+
+    $preview = $component->getDockerComposeBuildCommandPreviewProperty();
+
+    // Should be ./docker-compose.yaml, NOT .//docker-compose.yaml
+    expect($preview)
+        ->toBeString()
+        ->toContain('./docker-compose.yaml')
+        ->not->toContain('.//');
+});
+
+it('correctly formats build command preview with nested baseDirectory', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/backend';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomBuildCommand = 'docker compose build';
+
+    $preview = $component->getDockerComposeBuildCommandPreviewProperty();
+
+    // Should be ./backend/docker-compose.yaml
+    expect($preview)
+        ->toBeString()
+        ->toContain('./backend/docker-compose.yaml');
+});
+
+it('correctly formats build command preview with deeply nested baseDirectory', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/apps/api/backend';
+    $component->dockerComposeLocation = '/docker-compose.prod.yaml';
+    $component->dockerComposeCustomBuildCommand = 'docker compose build';
+
+    $preview = $component->getDockerComposeBuildCommandPreviewProperty();
+
+    expect($preview)
+        ->toBeString()
+        ->toContain('./apps/api/backend/docker-compose.prod.yaml');
+});
+
+it('uses BUILD_TIME_ENV_PATH constant instead of hardcoded path in build command preview', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomBuildCommand = 'docker compose build';
+
+    $preview = $component->getDockerComposeBuildCommandPreviewProperty();
+
+    // Should contain the path from the constant
+    expect($preview)
+        ->toBeString()
+        ->toContain(ApplicationDeploymentJob::BUILD_TIME_ENV_PATH);
+});
+
+it('returns empty string for build command preview when no custom build command is set', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/backend';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomBuildCommand = null;
+
+    $preview = $component->getDockerComposeBuildCommandPreviewProperty();
+
+    expect($preview)->toBe('');
+});
+
+it('prevents double slashes in start command preview when baseDirectory is root', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomStartCommand = 'docker compose up -d';
+
+    $preview = $component->getDockerComposeStartCommandPreviewProperty();
+
+    // Should be ./docker-compose.yaml, NOT .//docker-compose.yaml
+    expect($preview)
+        ->toBeString()
+        ->toContain('./docker-compose.yaml')
+        ->not->toContain('.//');
+});
+
+it('correctly formats start command preview with nested baseDirectory', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/frontend';
+    $component->dockerComposeLocation = '/compose.yaml';
+    $component->dockerComposeCustomStartCommand = 'docker compose up -d';
+
+    $preview = $component->getDockerComposeStartCommandPreviewProperty();
+
+    expect($preview)
+        ->toBeString()
+        ->toContain('./frontend/compose.yaml');
+});
+
+it('uses workdir env placeholder in start command preview', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomStartCommand = 'docker compose up -d';
+
+    $preview = $component->getDockerComposeStartCommandPreviewProperty();
+
+    // Start command should use {workdir}/.env, not build-time env
+    expect($preview)
+        ->toBeString()
+        ->toContain('{workdir}/.env')
+        ->not->toContain(ApplicationDeploymentJob::BUILD_TIME_ENV_PATH);
+});
+
+it('returns empty string for start command preview when no custom start command is set', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/backend';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomStartCommand = null;
+
+    $preview = $component->getDockerComposeStartCommandPreviewProperty();
+
+    expect($preview)->toBe('');
+});
+
+it('handles baseDirectory with trailing slash correctly in build command', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/backend/';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomBuildCommand = 'docker compose build';
+
+    $preview = $component->getDockerComposeBuildCommandPreviewProperty();
+
+    // rtrim should remove trailing slash to prevent double slashes
+    expect($preview)
+        ->toBeString()
+        ->toContain('./backend/docker-compose.yaml')
+        ->not->toContain('backend//');
+});
+
+it('handles baseDirectory with trailing slash correctly in start command', function () {
+    $component = Mockery::mock(General::class)->makePartial();
+    $component->baseDirectory = '/backend/';
+    $component->dockerComposeLocation = '/docker-compose.yaml';
+    $component->dockerComposeCustomStartCommand = 'docker compose up -d';
+
+    $preview = $component->getDockerComposeStartCommandPreviewProperty();
+
+    // rtrim should remove trailing slash to prevent double slashes
+    expect($preview)
+        ->toBeString()
+        ->toContain('./backend/docker-compose.yaml')
+        ->not->toContain('backend//');
+});