diff --git a/.ai/lessons.md b/.ai/lessons.md
index 8b620a0887..cd37f876f5 100644
--- a/.ai/lessons.md
+++ b/.ai/lessons.md
@@ -61,3 +61,6 @@
 
 ## Test the real runtime image
 - Deployment shell commands run in the Alpine/BusyBox helper image and pass through the non-root sudo parser. Verify new flags and shell syntax in that image and with `parseCommandsByLineForSudo()`; faked command output hides both failures.
+
+## Format only your own files
+- `pint --dirty` also rewrites uncommitted files that belong to other work in the tree. When the tree has unrelated changes, pass your changed paths to Pint.
diff --git a/app/Http/Controllers/Api/ServersController.php b/app/Http/Controllers/Api/ServersController.php
index 67f9c6932f..76e36fe873 100644
--- a/app/Http/Controllers/Api/ServersController.php
+++ b/app/Http/Controllers/Api/ServersController.php
@@ -540,7 +540,7 @@ class ServersController extends Controller
         if ($serverRole === ServerRole::DEPLOYMENT && ! ModelsServer::buildServers($teamId)->exists()) {
             return response()->json([
                 'message' => 'Validation failed.',
-                'errors' => ['server_role' => ['Add another build-capable server before you set this server to deployments only.']],
+                'errors' => ['server_role' => ['Add a usable build server before you set this server to deployments only.']],
             ], 422);
         }
         if (is_null($request->instant_validate)) {
@@ -584,6 +584,7 @@ class ServersController extends Controller
 
         $server->settings()->update([
             'server_role' => $serverRole,
+            'is_build_server' => $serverRole === ServerRole::BUILD,
         ]);
         if ($request->instant_validate) {
             ValidateServer::dispatch($server);
@@ -763,7 +764,7 @@ class ServersController extends Controller
         if ($serverRole === ServerRole::DEPLOYMENT && ! ModelsServer::buildServers($teamId)->whereKeyNot($server->id)->exists()) {
             return response()->json([
                 'message' => 'Validation failed.',
-                'errors' => ['server_role' => ['Add another build-capable server before you set this server to deployments only.']],
+                'errors' => ['server_role' => ['Add a usable build server before you set this server to deployments only.']],
             ], 422);
         }
 
@@ -771,6 +772,7 @@ class ServersController extends Controller
         if ($serverRole !== null) {
             $server->settings()->update([
                 'server_role' => $serverRole,
+                'is_build_server' => $serverRole === ServerRole::BUILD,
             ]);
         }
 
diff --git a/app/Jobs/ApplicationDeploymentJob.php b/app/Jobs/ApplicationDeploymentJob.php
index e22dce607c..fb70c9c9cc 100644
--- a/app/Jobs/ApplicationDeploymentJob.php
+++ b/app/Jobs/ApplicationDeploymentJob.php
@@ -424,33 +424,39 @@ class ApplicationDeploymentJob implements ShouldBeEncrypted, ShouldQueue
 
     private function selectBuildServer(): void
     {
-        if (! data_get($this->application, 'settings.is_build_server_enabled')) {
-            $this->build_server = $this->server;
+        $this->build_server = $this->server;
 
+        // A deployments-only server never builds. Docker image and Compose applications are exempt:
+        // the first builds nothing and the second does not support build servers.
+        $mustBuildElsewhere = ! $this->server->canBuildApplications()
+            && ! in_array($this->application->build_pack, ['dockerimage', 'dockercompose'], true);
+
+        if (! $mustBuildElsewhere && ! data_get($this->application, 'settings.is_build_server_enabled')) {
             return;
         }
 
+        if ($mustBuildElsewhere && ! $this->restart_only && str($this->application->docker_registry_image_name)->isEmpty()) {
+            throw new DeploymentException("The deployment server ({$this->server->name}) is set to deployments only, so this application is built on a build server. Set a Docker image name in the application's General settings so the deployment server can pull the built image.");
+        }
+
         $team = $this->application->environment->project->team;
-        $buildServers = Server::buildServers($team->id)->get();
+        $buildServers = Server::buildServers($team->id)->whereKeyNot($this->server->id)->get();
 
         if ($buildServers->isEmpty()) {
+            // A restart only rebuilds when the image is missing, so it may still run on the deployment server.
+            if ($mustBuildElsewhere && ! $this->restart_only) {
+                throw new DeploymentException("The deployment server ({$this->server->name}) is set to deployments only, and no usable build server was found. Add a build server or change the server role.");
+            }
             if (! $team->is_build_server_fallback_enabled) {
                 throw new DeploymentException('No available dedicated build server was found. Enable a usable build server for this team or allow fallback to the deployment server in the team settings.');
             }
 
             $this->application_deployment_queue->addLogEntry('No suitable build server found. Using the deployment server.');
-            $this->build_server = $this->server;
 
             return;
         }
 
         $this->build_server = $buildServers->random();
-        if ($this->build_server->is($this->server)) {
-            $this->application_deployment_queue->addLogEntry("Using deployment server ({$this->server->name}) for the build.");
-
-            return;
-        }
-
         $this->application_deployment_queue->build_server_id = $this->build_server->id;
         $this->application_deployment_queue->addLogEntry("Found a suitable build server ({$this->build_server->name}).");
         $this->use_build_server = true;
diff --git a/app/Livewire/Server/Show.php b/app/Livewire/Server/Show.php
index cd435b56b6..a420de5b85 100644
--- a/app/Livewire/Server/Show.php
+++ b/app/Livewire/Server/Show.php
@@ -425,7 +425,7 @@ class Show extends Component
 
             if ($newRole === ServerRole::DEPLOYMENT && ! Server::buildServers($this->server->team_id)->whereKeyNot($this->server->id)->exists()) {
                 $this->serverRole = $currentRole->value;
-                $this->dispatch('error', 'Add another build-capable server before you set this server to deployments only.');
+                $this->dispatch('error', 'Add a usable build server before you set this server to deployments only.');
 
                 return;
             }
diff --git a/app/Models/Server.php b/app/Models/Server.php
index 20952d5598..3cc0ea3bbf 100644
--- a/app/Models/Server.php
+++ b/app/Models/Server.php
@@ -530,12 +530,27 @@ class Server extends BaseModel
             ->whereRelation('settings', 'force_disabled', false);
 
         return $isBuildServer
-            ? $query->whereHas('settings', fn (Builder $settings) => $settings
-                ->where('server_role', '!=', ServerRole::DEPLOYMENT->value)
-                ->orWhereNull('server_role'))
-            : $query->whereHas('settings', fn (Builder $settings) => $settings
-                ->where('server_role', '!=', ServerRole::BUILD->value)
-                ->orWhereNull('server_role'));
+            ? self::whereServerRole($query, ServerRole::BUILD)
+            : self::whereServerRole($query, ServerRole::DEPLOYMENT, ServerRole::BOTH);
+    }
+
+    /**
+     * Filters by the effective server role. A null role falls back to the legacy
+     * is_build_server flag, like ServerSetting::effectiveServerRole().
+     */
+    private static function whereServerRole(Builder $query, ServerRole ...$roles): Builder
+    {
+        $legacyBuildServerFlags = collect($roles)
+            ->reject(fn (ServerRole $role) => $role === ServerRole::DEPLOYMENT)
+            ->map(fn (ServerRole $role) => $role === ServerRole::BUILD)
+            ->values()
+            ->all();
+
+        return $query->whereHas('settings', fn (Builder $settings) => $settings
+            ->whereIn('server_role', array_map(fn (ServerRole $role) => $role->value, $roles))
+            ->orWhere(fn (Builder $legacy) => $legacy
+                ->whereNull('server_role')
+                ->whereIn('is_build_server', $legacyBuildServerFlags)));
     }
 
     public function canHostResources(): bool
@@ -929,16 +944,19 @@ $siteAddress {
         return $this->ip === 'host.docker.internal' || $this->id === 0;
     }
 
-    public static function buildServers($teamId)
+    /**
+     * Usable dedicated (build-only) servers of a team. Servers with the combined role
+     * host deployments, so they are never picked as build servers.
+     */
+    public static function buildServers($teamId): Builder
     {
-        return Server::whereTeamId($teamId)
+        $query = Server::whereTeamId($teamId)
             ->whereRelation('settings', 'is_reachable', true)
             ->whereRelation('settings', 'is_usable', true)
             ->whereRelation('settings', 'is_swarm_worker', false)
-            ->whereHas('settings', fn (Builder $settings) => $settings
-                ->where('server_role', '!=', ServerRole::DEPLOYMENT->value)
-                ->orWhereNull('server_role'))
             ->whereRelation('settings', 'force_disabled', false);
+
+        return self::whereServerRole($query, ServerRole::BUILD);
     }
 
     public function isForceDisabled()
diff --git a/resources/views/livewire/project/application/general.blade.php b/resources/views/livewire/project/application/general.blade.php
index 6f7323ce41..8057209805 100644
--- a/resources/views/livewire/project/application/general.blade.php
+++ b/resources/views/livewire/project/application/general.blade.php
@@ -401,7 +401,8 @@
                         @if (
                             $application->destination->server->isSwarm() ||
                                 $application->additional_servers->count() > 0 ||
-                                $application->settings->is_build_server_enabled)
+                                $application->settings->is_build_server_enabled ||
+                                ! $application->destination->server->canBuildApplications())
                             <x-forms.input id="dockerRegistryImageName" required label="Image"
                                 placeholder="ghcr.io/your-org/your-app" x-bind:disabled="!canUpdate" />
                             <x-forms.input id="dockerRegistryImageTag"
diff --git a/tests/Feature/ApplicationGeneralLayoutTest.php b/tests/Feature/ApplicationGeneralLayoutTest.php
index ceff52b3e7..889f1318b2 100644
--- a/tests/Feature/ApplicationGeneralLayoutTest.php
+++ b/tests/Feature/ApplicationGeneralLayoutTest.php
@@ -61,3 +61,16 @@ test('onboarding uses the reusable advanced settings component', function () {
         ->and($onboarding)
         ->toContain('<x-forms.collapsible title="Advanced Connection Settings"');
 });
+
+test('deployments-only servers require a registry image because builds run elsewhere', function () {
+    $view = file_get_contents(resource_path('views/livewire/project/application/general.blade.php'));
+    $requiredImageCondition = str($view)
+        ->after("@if (\$application->build_pack === 'dockerimage')")
+        ->after('@else')
+        ->before('<x-forms.input id="dockerRegistryImageName" required label="Image"')
+        ->toString();
+
+    expect($requiredImageCondition)
+        ->toContain('$application->settings->is_build_server_enabled')
+        ->toContain('! $application->destination->server->canBuildApplications()');
+});
diff --git a/tests/Feature/BuildServerFallbackPolicyTest.php b/tests/Feature/BuildServerFallbackPolicyTest.php
index 2fd3b2f72a..e698a205b4 100644
--- a/tests/Feature/BuildServerFallbackPolicyTest.php
+++ b/tests/Feature/BuildServerFallbackPolicyTest.php
@@ -23,7 +23,7 @@ afterEach(function () {
     Server::flushIdentityMap();
 });
 
-function makeBuildServerSelectionJob(Team $team, Server $deploymentServer): array
+function makeBuildServerSelectionJob(Team $team, Server $deploymentServer, array $applicationAttributes = [], bool $buildServerEnabled = true, bool $restartOnly = false): array
 {
     $project = new Project;
     $project->setRelation('team', $team);
@@ -32,9 +32,10 @@ function makeBuildServerSelectionJob(Team $team, Server $deploymentServer): arra
     $environment->setRelation('project', $project);
 
     $settings = new ApplicationSetting;
-    $settings->is_build_server_enabled = true;
+    $settings->is_build_server_enabled = $buildServerEnabled;
 
     $application = new Application;
+    $application->forceFill(array_merge(['build_pack' => 'nixpacks'], $applicationAttributes));
     $application->setRelation('environment', $environment);
     $application->setRelation('settings', $settings);
 
@@ -45,6 +46,7 @@ function makeBuildServerSelectionJob(Team $team, Server $deploymentServer): arra
         'application' => $application,
         'application_deployment_queue' => $deploymentQueue,
         'server' => $deploymentServer,
+        'restart_only' => $restartOnly,
     ] as $property => $value) {
         (new ReflectionProperty(ApplicationDeploymentJob::class, $property))->setValue($job, $value);
     }
@@ -62,6 +64,26 @@ function selectedBuildServer(ApplicationDeploymentJob $job): Server
     return (new ReflectionProperty(ApplicationDeploymentJob::class, 'build_server'))->getValue($job);
 }
 
+function usesRemoteBuildServer(ApplicationDeploymentJob $job): bool
+{
+    return (new ReflectionProperty(ApplicationDeploymentJob::class, 'use_build_server'))->getValue($job);
+}
+
+function makeRoleServer(Team $team, string $role): Server
+{
+    $server = Server::factory()->create(['team_id' => $team->id]);
+    $server->settings()->update([
+        'is_reachable' => true,
+        'is_usable' => true,
+        'server_role' => $role,
+        'is_build_server' => $role === 'build',
+        'is_swarm_worker' => false,
+        'force_disabled' => false,
+    ]);
+
+    return $server->fresh();
+}
+
 test('teams allow deployment server fallback by default', function () {
     $team = Team::factory()->create();
     $deploymentServer = Server::factory()->create(['team_id' => $team->id]);
@@ -136,28 +158,144 @@ test('strict teams use an available dedicated build server', function () {
     expect(selectedBuildServer($job)->is($buildServer))->toBeTrue();
 });
 
-test('a combined deployment server builds locally without remote build handling', function () {
+test('strict teams do not treat combined servers as dedicated build servers', function () {
     $team = Team::factory()->create(['is_build_server_fallback_enabled' => false]);
-    $deploymentServer = Server::factory()->create(['team_id' => $team->id]);
-    $deploymentServer->settings()->update([
-        'server_role' => 'both',
-        'is_build_server' => false,
-        'is_reachable' => true,
-        'is_usable' => true,
-        'is_swarm_worker' => false,
-        'force_disabled' => false,
-    ]);
+    $deploymentServer = makeRoleServer($team, 'both');
+    makeRoleServer($team, 'both');
     [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer);
 
-    $deploymentQueue->shouldNotReceive('setAttribute');
-    $deploymentQueue->shouldReceive('addLogEntry')
-        ->once()
-        ->with("Using deployment server ({$deploymentServer->name}) for the build.");
+    $deploymentQueue->shouldNotReceive('addLogEntry');
+
+    expect(fn () => invokeBuildServerSelection($job))
+        ->toThrow(DeploymentException::class, 'No available dedicated build server was found.');
+});
+
+test('build server selection only picks dedicated build servers', function () {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'both');
+    makeRoleServer($team, 'both');
+    makeRoleServer($team, 'both');
+    makeRoleServer($team, 'deployment');
+    $buildServer = makeRoleServer($team, 'build');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer);
+
+    $deploymentQueue->shouldReceive('setAttribute')->with('build_server_id', $buildServer->id)->once()->andReturnSelf();
+    $deploymentQueue->shouldReceive('addLogEntry')->once()->with("Found a suitable build server ({$buildServer->name}).");
 
     invokeBuildServerSelection($job);
 
-    $useBuildServer = (new ReflectionProperty(ApplicationDeploymentJob::class, 'use_build_server'))->getValue($job);
+    expect(selectedBuildServer($job)->is($buildServer))->toBeTrue()
+        ->and(usesRemoteBuildServer($job))->toBeTrue();
+});
+
+test('fallback builds on the deployment server instead of another combined server', function () {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'both');
+    makeRoleServer($team, 'both');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer);
+
+    $deploymentQueue->shouldNotReceive('setAttribute');
+    $deploymentQueue->shouldReceive('addLogEntry')->once()->with('No suitable build server found. Using the deployment server.');
+
+    invokeBuildServerSelection($job);
 
     expect(selectedBuildServer($job)->is($deploymentServer))->toBeTrue()
-        ->and($useBuildServer)->toBeFalse();
+        ->and(usesRemoteBuildServer($job))->toBeFalse();
+});
+
+test('deployments-only servers build on a dedicated build server without the application setting', function () {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'deployment');
+    makeRoleServer($team, 'both');
+    $buildServer = makeRoleServer($team, 'build');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, ['docker_registry_image_name' => 'ghcr.io/coollabsio/app'], buildServerEnabled: false);
+
+    $deploymentQueue->shouldReceive('setAttribute')->with('build_server_id', $buildServer->id)->once()->andReturnSelf();
+    $deploymentQueue->shouldReceive('addLogEntry')->once()->with("Found a suitable build server ({$buildServer->name}).");
+
+    invokeBuildServerSelection($job);
+
+    expect(selectedBuildServer($job)->is($buildServer))->toBeTrue()
+        ->and(usesRemoteBuildServer($job))->toBeTrue();
+});
+
+test('deployments-only servers never fall back to building themselves', function (bool $buildServerEnabled) {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'deployment');
+    makeRoleServer($team, 'both');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, ['docker_registry_image_name' => 'ghcr.io/coollabsio/app'], $buildServerEnabled);
+
+    $deploymentQueue->shouldNotReceive('addLogEntry');
+
+    expect(fn () => invokeBuildServerSelection($job))
+        ->toThrow(DeploymentException::class, "The deployment server ({$deploymentServer->name}) is set to deployments only");
+})->with([
+    'application uses a build server' => [true],
+    'application builds on the deployment server' => [false],
+]);
+
+test('deployments-only servers need a registry image for remote builds', function () {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'deployment');
+    makeRoleServer($team, 'build');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, buildServerEnabled: false);
+
+    $deploymentQueue->shouldNotReceive('addLogEntry');
+
+    expect(fn () => invokeBuildServerSelection($job))
+        ->toThrow(DeploymentException::class, 'Set a Docker image name');
+});
+
+test('deployments-only servers restart without a registry image', function () {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'deployment');
+    $buildServer = makeRoleServer($team, 'build');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, buildServerEnabled: false, restartOnly: true);
+
+    $deploymentQueue->shouldReceive('setAttribute')->with('build_server_id', $buildServer->id)->once()->andReturnSelf();
+    $deploymentQueue->shouldReceive('addLogEntry')->once()->with("Found a suitable build server ({$buildServer->name}).");
+
+    invokeBuildServerSelection($job);
+
+    expect(selectedBuildServer($job)->is($buildServer))->toBeTrue();
+});
+
+test('deployments-only servers can restart when no build server is available', function () {
+    $team = Team::factory()->create();
+    $deploymentServer = makeRoleServer($team, 'deployment');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, buildServerEnabled: false, restartOnly: true);
+
+    $deploymentQueue->shouldReceive('addLogEntry')->once()->with('No suitable build server found. Using the deployment server.');
+
+    invokeBuildServerSelection($job);
+
+    expect(selectedBuildServer($job)->is($deploymentServer))->toBeTrue()
+        ->and(usesRemoteBuildServer($job))->toBeFalse();
+});
+
+test('deployments-only servers do not need a build server when nothing is built', function (string $buildPack) {
+    $team = Team::factory()->create(['is_build_server_fallback_enabled' => false]);
+    $deploymentServer = makeRoleServer($team, 'deployment');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, ['build_pack' => $buildPack], buildServerEnabled: false);
+
+    $deploymentQueue->shouldNotReceive('addLogEntry');
+
+    invokeBuildServerSelection($job);
+
+    expect(selectedBuildServer($job)->is($deploymentServer))->toBeTrue()
+        ->and(usesRemoteBuildServer($job))->toBeFalse();
+})->with(['dockerimage', 'dockercompose']);
+
+test('applications on combined servers build locally unless they use a build server', function () {
+    $team = Team::factory()->create(['is_build_server_fallback_enabled' => false]);
+    $deploymentServer = makeRoleServer($team, 'both');
+    makeRoleServer($team, 'build');
+    [$job, $deploymentQueue] = makeBuildServerSelectionJob($team, $deploymentServer, buildServerEnabled: false);
+
+    $deploymentQueue->shouldNotReceive('addLogEntry');
+
+    invokeBuildServerSelection($job);
+
+    expect(selectedBuildServer($job)->is($deploymentServer))->toBeTrue()
+        ->and(usesRemoteBuildServer($job))->toBeFalse();
 });
diff --git a/tests/Feature/ResourceHostingServerTest.php b/tests/Feature/ResourceHostingServerTest.php
index af64673caa..28b6bb2632 100644
--- a/tests/Feature/ResourceHostingServerTest.php
+++ b/tests/Feature/ResourceHostingServerTest.php
@@ -86,7 +86,34 @@ test('legacy server settings with a null role use the combined role', function (
     expect($this->server->settings->effectiveServerRole()->value)->toBe('both')
         ->and($this->server->canHostResources())->toBeTrue()
         ->and(Server::isUsable()->pluck('id'))->toContain($this->server->id)
-        ->and(Server::isUsableBuildServer()->pluck('id'))->toContain($this->server->id);
+        ->and(Server::isUsableBuildServer()->pluck('id'))->not->toContain($this->server->id)
+        ->and(Server::buildServers($this->team->id)->pluck('id'))->not->toContain($this->server->id);
+});
+
+test('legacy build servers with a null role stay build only', function () {
+    $this->actingAs($this->user);
+    $this->server->settings()->update(['server_role' => null, 'is_build_server' => true]);
+    $this->server->refresh()->load('settings');
+
+    expect($this->server->settings->effectiveServerRole()->value)->toBe('build')
+        ->and(Server::isUsable()->pluck('id'))->not->toContain($this->server->id)
+        ->and(Server::isUsableBuildServer()->pluck('id'))->toContain($this->server->id)
+        ->and(Server::buildServers($this->team->id)->pluck('id'))->toContain($this->server->id);
+});
+
+test('deployments only requires a dedicated build server, not a combined server', function () {
+    $combinedServer = Server::factory()->create(['team_id' => $this->team->id]);
+    $combinedServer->settings()->update(['server_role' => 'both',
+        'is_build_server' => false, 'is_reachable' => true, 'is_usable' => true]);
+
+    Livewire::actingAs($this->user)
+        ->test(Show::class, ['server_uuid' => $this->server->uuid])
+        ->set('serverRole', 'deployment')
+        ->call('requestServerRoleChange')
+        ->assertSet('serverRole', 'both')
+        ->assertDispatched('error');
+
+    expect($this->server->settings->fresh()->server_role->value)->toBe('both');
 });
 
 test('changing from build only to deployments and builds requires confirmation', function () {
@@ -169,11 +196,31 @@ test('resource selection keeps excluded build servers visible for explanation',
     expect($component->servers->pluck('id'))->toContain($this->server->id)
         ->not->toContain($buildServer->id)
         ->and(Server::isUsableBuildServer()->pluck('id'))->toContain($buildServer->id)
-        ->toContain($this->server->id)
+        ->not->toContain($this->server->id)
         ->and($component->buildServers->pluck('id'))->toContain($buildServer->id)
         ->and($component->allServers->pluck('id'))->toContain($this->server->id, $buildServer->id);
 });
 
+test('resource selection lists each combined server once', function () {
+    $this->actingAs($this->user);
+    $otherServer = Server::factory()->create(['team_id' => $this->team->id]);
+    $otherServer->settings()->update([
+        'is_reachable' => true,
+        'is_usable' => true,
+        'server_role' => 'both',
+        'is_build_server' => false,
+        'is_swarm_worker' => false,
+        'force_disabled' => false,
+    ]);
+
+    $component = new ResourceSelect;
+    $component->loadServers();
+
+    expect($component->buildServers)->toBeEmpty()
+        ->and($component->servers->pluck('id')->all())->toEqualCanonicalizing([$this->server->id, $otherServer->id])
+        ->and($component->allServers->pluck('id')->duplicates())->toBeEmpty();
+});
+
 test('resource selection does not show the empty server message when only build servers are available', function () {
     $html = Blade::render(
         file_get_contents(resource_path('views/livewire/project/new/select.blade.php')),
diff --git a/tests/Feature/ServerUpdatePrivateKeyApiTest.php b/tests/Feature/ServerUpdatePrivateKeyApiTest.php
index 2b67e7b83d..7940c0d9a1 100644
--- a/tests/Feature/ServerUpdatePrivateKeyApiTest.php
+++ b/tests/Feature/ServerUpdatePrivateKeyApiTest.php
@@ -134,7 +134,20 @@ it('rejects the legacy build server API field', function () {
         ->assertJsonValidationErrors('is_build_server');
 });
 
-it('requires another build-capable server before selecting deployment only', function () {
+it('requires a dedicated build server before selecting deployment only', function () {
+    patchServerUpdatePrivateKeyApi($this, $this->server, $this->bearerToken, [
+        'server_role' => 'deployment',
+    ])->assertUnprocessable()
+        ->assertJsonValidationErrors('server_role');
+
+    $combinedServer = Server::factory()->create(['team_id' => $this->team->id]);
+    $combinedServer->settings()->update([
+        'is_reachable' => true,
+        'is_usable' => true,
+        'server_role' => 'both',
+        'is_build_server' => false,
+    ]);
+
     patchServerUpdatePrivateKeyApi($this, $this->server, $this->bearerToken, [
         'server_role' => 'deployment',
     ])->assertUnprocessable()
@@ -165,7 +178,22 @@ it('creates a server with an API server role', function () {
 
     $server = Server::whereUuid($response->json('uuid'))->firstOrFail();
 
-    expect($server->settings->server_role->value)->toBe('build');
+    expect($server->settings->server_role->value)->toBe('build')
+        ->and($server->settings->is_build_server)->toBeTrue();
+});
+
+it('keeps the legacy build server flag in sync when the API changes the role', function () {
+    patchServerUpdatePrivateKeyApi($this, $this->server, $this->bearerToken, [
+        'server_role' => 'build',
+    ])->assertCreated();
+
+    expect($this->server->settings->fresh()->is_build_server)->toBeTrue();
+
+    patchServerUpdatePrivateKeyApi($this, $this->server, $this->bearerToken, [
+        'server_role' => 'both',
+    ])->assertCreated();
+
+    expect($this->server->settings->fresh()->is_build_server)->toBeFalse();
 });
 
 it('rejects an invalid API server role', function () {