diff --git a/app/Jobs/ApplicationDeploymentJob.php b/app/Jobs/ApplicationDeploymentJob.php
index 994d9ad657..810f3336c9 100644
--- a/app/Jobs/ApplicationDeploymentJob.php
+++ b/app/Jobs/ApplicationDeploymentJob.php
@@ -4970,7 +4970,7 @@ COPY ./nginx.conf /etc/nginx/conf.d/default.conf");
 
             $dockerfilePath = $this->resolveComposeDockerfilePath($service['build']);
             if ($dockerfilePath === null) {
-                $this->application_deployment_queue->addLogEntry("The build context of service {$serviceName} is remote or uses variables, skipping ARG injection.");
+                $this->application_deployment_queue->addLogEntry($this->composeArgInjectionSkippedMessage((string) $serviceName, $service['build'], $variables));
 
                 continue;
             }
@@ -5128,6 +5128,41 @@ COPY ./nginx.conf /etc/nginx/conf.d/default.conf");
         return str_starts_with($dockerfile, '/') ? $dockerfile : rtrim($context, '/').'/'.$dockerfile;
     }
 
+    /**
+     * Tells the user why Coolify cannot add ARG lines to a Compose service Dockerfile, and which
+     * build-time variables to declare there. Only valid variable names are shown, never values.
+     *
+     * @param  Collection<string, mixed>  $variables
+     */
+    private function composeArgInjectionSkippedMessage(string $serviceName, mixed $build, Collection $variables): string
+    {
+        $context = is_string($build) ? $build : data_get($build, 'context');
+        $dockerfile = is_array($build) ? data_get($build, 'dockerfile') : null;
+
+        $reason = match (true) {
+            is_array($build) && array_key_exists('dockerfile_inline', $build) => 'the service uses an inline Dockerfile (dockerfile_inline)',
+            is_string($context) && preg_match('~^[a-z][a-z0-9+.-]*://|^git@~i', $context) === 1 => 'the build context is a remote Git URL',
+            (is_string($context) && str_contains($context, '$')) || (is_string($dockerfile) && str_contains($dockerfile, '$')) => 'the build context or Dockerfile path uses variables',
+            default => 'Coolify cannot read the build definition',
+        };
+
+        $names = $variables->keys()
+            ->map(fn ($key) => (string) $key)
+            ->filter(fn (string $key) => ValidationPatterns::isValidEnvironmentVariableKey($key))
+            ->sortBy(fn (string $key) => str_starts_with($key, 'COOLIFY_') ? 1 : 0)
+            ->values();
+
+        $message = "Skipping ARG injection for service {$serviceName}: {$reason}. Docker ignores build-time variables that the Dockerfile does not declare, so add 'ARG <NAME>' lines to the Dockerfile for the ones you need";
+        if ($names->isEmpty()) {
+            return "{$message}.";
+        }
+
+        $listedNames = $names->take(10)->implode(', ');
+        $moreCount = $names->count() - 10;
+
+        return $moreCount > 0 ? "{$message}: {$listedNames} and {$moreCount} more." : "{$message}: {$listedNames}.";
+    }
+
     private function add_build_secrets_to_compose($composeFile)
     {
         // Generate env variables if not already done
diff --git a/tests/Feature/ComposeBuildContextDeploymentTest.php b/tests/Feature/ComposeBuildContextDeploymentTest.php
index 581179a47f..d515a815d5 100644
--- a/tests/Feature/ComposeBuildContextDeploymentTest.php
+++ b/tests/Feature/ComposeBuildContextDeploymentTest.php
@@ -58,7 +58,7 @@ function composeDockerfile(string $path): string
     return $path;
 }
 
-function runComposeArgInjection(object $test, mixed $build, string $workdir): LocallyExecutedComposeDeploymentJob
+function runComposeArgInjection(object $test, mixed $build, string $workdir, array $envArgs = ['APP_ENV' => 'production']): LocallyExecutedComposeDeploymentJob
 {
     $application = Application::factory()->create(['build_pack' => 'dockercompose']);
     $application->settings()->update(['inject_build_args_to_dockerfile' => true]);
@@ -76,7 +76,7 @@ function runComposeArgInjection(object $test, mixed $build, string $workdir): Lo
         'deployment_uuid' => 'deployment-uuid',
         'basedir' => $test->basedir,
         'workdir' => $workdir,
-        'env_args' => collect(['APP_ENV' => 'production']),
+        'env_args' => collect($envArgs),
         'saved_outputs' => collect(),
         'dockerSecretsSupported' => false,
         'pull_request_id' => 0,
@@ -106,19 +106,45 @@ test('compose deployments inject build args for Dockerfiles inside the repositor
     'custom Dockerfile in a parent folder' => [['context' => 'services/api', 'dockerfile' => '../docker/api.Dockerfile'], '', 'services/docker/api.Dockerfile'],
 ]);
 
-test('compose deployments skip build contexts they cannot inspect locally', function (mixed $build) {
+test('compose deployments skip build contexts they cannot inspect locally', function (mixed $build, string $reason) {
     $dockerfile = composeDockerfile($this->basedir.'/Dockerfile');
 
-    $job = runComposeArgInjection($this, $build, $this->basedir);
+    $job = runComposeArgInjection($this, $build, $this->basedir, [
+        'COOLIFY_URL' => 'https://secret-host.example.com',
+        'APP_ENV' => 'production-secret-value',
+        'API_TOKEN' => 'super-secret-token',
+    ]);
 
     expect(file_get_contents($dockerfile))->not->toContain('ARG APP_ENV')
-        ->and($job->logEntries)->toContain('The build context of service api is remote or uses variables, skipping ARG injection.');
+        ->and($job->logEntries)->toContain("Skipping ARG injection for service api: {$reason}. Docker ignores build-time variables that the Dockerfile does not declare, so add 'ARG <NAME>' lines to the Dockerfile for the ones you need: APP_ENV, API_TOKEN, COOLIFY_URL.")
+        ->and(implode("\n", $job->logEntries))->not->toContain('secret');
 })->with([
-    'git URL' => ['https://github.com/coollabsio/coolify.git#main:docker'],
-    'context variable' => ['${APP_DIR:-.}'],
-    'inline Dockerfile' => [['context' => '.', 'dockerfile_inline' => "FROM alpine\n"]],
+    'git URL' => ['https://github.com/coollabsio/coolify.git#main:docker', 'the build context is a remote Git URL'],
+    'git SSH URL' => [['context' => 'git@github.com:coollabsio/coolify.git'], 'the build context is a remote Git URL'],
+    'context variable' => ['${APP_DIR:-.}', 'the build context or Dockerfile path uses variables'],
+    'Dockerfile variable' => [['context' => '.', 'dockerfile' => '${DOCKERFILE}'], 'the build context or Dockerfile path uses variables'],
+    'inline Dockerfile' => [['context' => '.', 'dockerfile_inline' => "FROM alpine\n"], 'the service uses an inline Dockerfile (dockerfile_inline)'],
+    'invalid build definition' => [['context' => ['nested']], 'Coolify cannot read the build definition'],
 ]);
 
+test('skipped ARG injection lists at most ten build-time variable names', function () {
+    composeDockerfile($this->basedir.'/Dockerfile');
+    $envArgs = collect(range(1, 13))->mapWithKeys(fn (int $number) => ["VAR_{$number}" => "value-{$number}"])->all();
+
+    $job = runComposeArgInjection($this, '${APP_DIR}', $this->basedir, $envArgs);
+
+    expect($job->logEntries)->toContain("Skipping ARG injection for service api: the build context or Dockerfile path uses variables. Docker ignores build-time variables that the Dockerfile does not declare, so add 'ARG <NAME>' lines to the Dockerfile for the ones you need: VAR_1, VAR_2, VAR_3, VAR_4, VAR_5, VAR_6, VAR_7, VAR_8, VAR_9, VAR_10 and 3 more.")
+        ->and(implode("\n", $job->logEntries))->not->toContain('value-');
+});
+
+test('skipped ARG injection does not show invalid build-time variable names', function () {
+    composeDockerfile($this->basedir.'/Dockerfile');
+
+    $job = runComposeArgInjection($this, '${APP_DIR}', $this->basedir, ['BAD NAME;id' => 'x', 'GOOD_NAME' => 'y']);
+
+    expect($job->logEntries)->toContain("Skipping ARG injection for service api: the build context or Dockerfile path uses variables. Docker ignores build-time variables that the Dockerfile does not declare, so add 'ARG <NAME>' lines to the Dockerfile for the ones you need: GOOD_NAME.");
+});
+
 test('compose deployments never change Dockerfiles outside the repository', function (string $escape) {
     $outside = composeDockerfile($this->root.'/outside/Dockerfile');
     symlink($this->root.'/outside', $this->basedir.'/linked');