diff --git a/app/Actions/Signature/CreateSignature.php b/app/Actions/Signature/CreateSignature.php
new file mode 100644
index 00000000..2aedeb2e
--- /dev/null
+++ b/app/Actions/Signature/CreateSignature.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Actions\Signature;
+
+use App\Models\Workspace;
+use App\Models\WorkspaceSignature;
+
+class CreateSignature
+{
+    public static function execute(Workspace $workspace, array $data): WorkspaceSignature
+    {
+        return $workspace->signatures()->create([
+            'name' => data_get($data, 'name'),
+            'content' => data_get($data, 'content'),
+        ]);
+    }
+}
diff --git a/app/Actions/Signature/DeleteSignature.php b/app/Actions/Signature/DeleteSignature.php
new file mode 100644
index 00000000..896e0616
--- /dev/null
+++ b/app/Actions/Signature/DeleteSignature.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Actions\Signature;
+
+use App\Models\WorkspaceSignature;
+
+class DeleteSignature
+{
+    public static function execute(WorkspaceSignature $signature): void
+    {
+        $signature->delete();
+    }
+}
diff --git a/app/Actions/Signature/UpdateSignature.php b/app/Actions/Signature/UpdateSignature.php
new file mode 100644
index 00000000..f02319ac
--- /dev/null
+++ b/app/Actions/Signature/UpdateSignature.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Actions\Signature;
+
+use App\Models\WorkspaceSignature;
+
+class UpdateSignature
+{
+    public static function execute(WorkspaceSignature $signature, array $data): WorkspaceSignature
+    {
+        $signature->update([
+            'name' => data_get($data, 'name'),
+            'content' => data_get($data, 'content'),
+        ]);
+
+        return $signature;
+    }
+}
diff --git a/app/Http/Controllers/Api/SignatureController.php b/app/Http/Controllers/Api/SignatureController.php
new file mode 100644
index 00000000..e03ef901
--- /dev/null
+++ b/app/Http/Controllers/Api/SignatureController.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers\Api;
+
+use App\Actions\Signature\CreateSignature;
+use App\Actions\Signature\DeleteSignature;
+use App\Actions\Signature\UpdateSignature;
+use App\Http\Requests\Api\Signature\StoreSignatureRequest;
+use App\Http\Requests\Api\Signature\UpdateSignatureRequest;
+use App\Http\Resources\Api\SignatureResource;
+use App\Models\WorkspaceSignature;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\AnonymousResourceCollection;
+use Symfony\Component\HttpFoundation\Response;
+
+class SignatureController extends Controller
+{
+    public function index(Request $request): AnonymousResourceCollection
+    {
+        $signatures = $request->workspace->signatures()->latest()->get();
+
+        return SignatureResource::collection($signatures);
+    }
+
+    public function store(StoreSignatureRequest $request): JsonResponse
+    {
+        $signature = CreateSignature::execute($request->workspace, $request->validated());
+
+        return (new SignatureResource($signature))
+            ->response()
+            ->setStatusCode(Response::HTTP_CREATED);
+    }
+
+    public function update(UpdateSignatureRequest $request, WorkspaceSignature $signature): SignatureResource
+    {
+        if ($signature->workspace_id !== $request->workspace->id) {
+            abort(Response::HTTP_NOT_FOUND);
+        }
+
+        $signature = UpdateSignature::execute($signature, $request->validated());
+
+        return new SignatureResource($signature);
+    }
+
+    public function destroy(Request $request, WorkspaceSignature $signature): JsonResponse
+    {
+        if ($signature->workspace_id !== $request->workspace->id) {
+            abort(Response::HTTP_NOT_FOUND);
+        }
+
+        DeleteSignature::execute($signature);
+
+        return response()->json(null, Response::HTTP_NO_CONTENT);
+    }
+}
diff --git a/app/Http/Controllers/App/WorkspaceSignatureController.php b/app/Http/Controllers/App/WorkspaceSignatureController.php
new file mode 100644
index 00000000..f0d583ca
--- /dev/null
+++ b/app/Http/Controllers/App/WorkspaceSignatureController.php
@@ -0,0 +1,113 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers\App;
+
+use App\Actions\Signature\CreateSignature;
+use App\Actions\Signature\DeleteSignature;
+use App\Actions\Signature\UpdateSignature;
+use App\Models\WorkspaceSignature;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Inertia\Inertia;
+use Inertia\Response;
+
+class WorkspaceSignatureController extends Controller
+{
+    public function index(Request $request): Response|RedirectResponse
+    {
+        $workspace = $request->user()->currentWorkspace;
+
+        if (! $workspace) {
+            return redirect()->route('app.workspaces.create');
+        }
+
+        $this->authorize('createPost', $workspace);
+
+        $signatures = $workspace->signatures()
+            ->when($request->input('search'), fn ($query, $search) => $query->where('name', 'ilike', "%{$search}%"))
+            ->latest()
+            ->paginate(config('app.pagination.default'));
+
+        return Inertia::render('signatures/Index', [
+            'workspace' => $workspace,
+            'signatures' => Inertia::scroll(fn () => $signatures),
+            'filters' => [
+                'search' => $request->input('search', ''),
+            ],
+        ]);
+    }
+
+    public function store(Request $request): RedirectResponse
+    {
+        $workspace = $request->user()->currentWorkspace;
+
+        if (! $workspace) {
+            return redirect()->route('app.workspaces.create');
+        }
+
+        $this->authorize('createPost', $workspace);
+
+        $validated = $request->validate([
+            'name' => ['required', 'string', 'max:255'],
+            'content' => ['required', 'string'],
+        ]);
+
+        CreateSignature::execute($workspace, $validated);
+
+        session()->flash('flash.banner', __('signatures.flash.created'));
+        session()->flash('flash.bannerStyle', 'success');
+
+        return redirect()->route('app.signatures.index');
+    }
+
+    public function update(Request $request, WorkspaceSignature $signature): RedirectResponse
+    {
+        $workspace = $request->user()->currentWorkspace;
+
+        if (! $workspace) {
+            return redirect()->route('app.workspaces.create');
+        }
+
+        $this->authorize('createPost', $workspace);
+
+        if ($signature->workspace_id !== $workspace->id) {
+            abort(404);
+        }
+
+        $validated = $request->validate([
+            'name' => ['required', 'string', 'max:255'],
+            'content' => ['required', 'string'],
+        ]);
+
+        UpdateSignature::execute($signature, $validated);
+
+        session()->flash('flash.banner', __('signatures.flash.updated'));
+        session()->flash('flash.bannerStyle', 'success');
+
+        return redirect()->route('app.signatures.index');
+    }
+
+    public function destroy(Request $request, WorkspaceSignature $signature): RedirectResponse
+    {
+        $workspace = $request->user()->currentWorkspace;
+
+        if (! $workspace) {
+            return redirect()->route('app.workspaces.create');
+        }
+
+        $this->authorize('createPost', $workspace);
+
+        if ($signature->workspace_id !== $workspace->id) {
+            abort(404);
+        }
+
+        DeleteSignature::execute($signature);
+
+        session()->flash('flash.banner', __('signatures.flash.deleted'));
+        session()->flash('flash.bannerStyle', 'success');
+
+        return redirect()->route('app.signatures.index');
+    }
+}
diff --git a/app/Http/Requests/Api/Signature/StoreSignatureRequest.php b/app/Http/Requests/Api/Signature/StoreSignatureRequest.php
new file mode 100644
index 00000000..ee83a5f5
--- /dev/null
+++ b/app/Http/Requests/Api/Signature/StoreSignatureRequest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Requests\Api\Signature;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class StoreSignatureRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function rules(): array
+    {
+        return [
+            'name' => ['required', 'string', 'max:255'],
+            'content' => ['required', 'string'],
+        ];
+    }
+}
diff --git a/app/Http/Requests/Api/Signature/UpdateSignatureRequest.php b/app/Http/Requests/Api/Signature/UpdateSignatureRequest.php
new file mode 100644
index 00000000..1d12b586
--- /dev/null
+++ b/app/Http/Requests/Api/Signature/UpdateSignatureRequest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Requests\Api\Signature;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class UpdateSignatureRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function rules(): array
+    {
+        return [
+            'name' => ['required', 'string', 'max:255'],
+            'content' => ['required', 'string'],
+        ];
+    }
+}
diff --git a/app/Http/Resources/Api/SignatureResource.php b/app/Http/Resources/Api/SignatureResource.php
new file mode 100644
index 00000000..879b3aec
--- /dev/null
+++ b/app/Http/Resources/Api/SignatureResource.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Resources\Api;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+class SignatureResource extends JsonResource
+{
+    /**
+     * @return array<string, mixed>
+     */
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->id,
+            'name' => $this->name,
+            'content' => $this->content,
+            'created_at' => $this->created_at->format('Y-m-d H:i:s'),
+            'updated_at' => $this->updated_at->format('Y-m-d H:i:s'),
+        ];
+    }
+}
diff --git a/app/Mcp/Tools/Signature/CreateSignatureTool.php b/app/Mcp/Tools/Signature/CreateSignatureTool.php
new file mode 100644
index 00000000..81ed8d60
--- /dev/null
+++ b/app/Mcp/Tools/Signature/CreateSignatureTool.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Mcp\Tools\Signature;
+
+use App\Actions\Signature\CreateSignature;
+use Illuminate\Contracts\JsonSchema\JsonSchema;
+use Laravel\Mcp\Request;
+use Laravel\Mcp\Response;
+use Laravel\Mcp\ResponseFactory;
+use Laravel\Mcp\Server\Attributes\Description;
+use Laravel\Mcp\Server\Tool;
+
+#[Description('Create a new signature with a name and content (hashtags, links, custom text, etc.).')]
+class CreateSignatureTool extends Tool
+{
+    public function handle(Request $request): ResponseFactory
+    {
+        $validated = $request->validate([
+            'name' => ['required', 'string', 'max:255'],
+            'content' => ['required', 'string'],
+        ]);
+
+        $signature = CreateSignature::execute($request->user()->currentWorkspace, $validated);
+
+        return Response::structured($signature->toArray());
+    }
+
+    public function schema(JsonSchema $schema): array
+    {
+        return [
+            'name' => $schema->string()->required()->description('The signature name.'),
+            'content' => $schema->string()->required()->description('The signature content (hashtags, links, custom text — anything you want to append to posts).'),
+        ];
+    }
+}
diff --git a/app/Mcp/Tools/Signature/DeleteSignatureTool.php b/app/Mcp/Tools/Signature/DeleteSignatureTool.php
new file mode 100644
index 00000000..ae2dade6
--- /dev/null
+++ b/app/Mcp/Tools/Signature/DeleteSignatureTool.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Mcp\Tools\Signature;
+
+use App\Actions\Signature\DeleteSignature;
+use App\Models\WorkspaceSignature;
+use Illuminate\Contracts\JsonSchema\JsonSchema;
+use Laravel\Mcp\Request;
+use Laravel\Mcp\Response;
+use Laravel\Mcp\ResponseFactory;
+use Laravel\Mcp\Server\Attributes\Description;
+use Laravel\Mcp\Server\Tool;
+
+#[Description('Delete a signature by ID.')]
+class DeleteSignatureTool extends Tool
+{
+    public function handle(Request $request): Response|ResponseFactory
+    {
+        $signature = WorkspaceSignature::where('workspace_id', $request->user()->current_workspace_id)
+            ->find(data_get($request->validate(['signature_id' => ['required', 'string']]), 'signature_id'));
+
+        if (! $signature) {
+            return Response::error('Signature not found.');
+        }
+
+        DeleteSignature::execute($signature);
+
+        return Response::structured(['deleted' => true]);
+    }
+
+    public function schema(JsonSchema $schema): array
+    {
+        return [
+            'signature_id' => $schema->string()->required()->description('The signature ID to delete.'),
+        ];
+    }
+}
diff --git a/app/Mcp/Tools/Signature/ListSignaturesTool.php b/app/Mcp/Tools/Signature/ListSignaturesTool.php
new file mode 100644
index 00000000..31d2e33e
--- /dev/null
+++ b/app/Mcp/Tools/Signature/ListSignaturesTool.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Mcp\Tools\Signature;
+
+use Laravel\Mcp\Request;
+use Laravel\Mcp\Response;
+use Laravel\Mcp\ResponseFactory;
+use Laravel\Mcp\Server\Attributes\Description;
+use Laravel\Mcp\Server\Tool;
+use Laravel\Mcp\Server\Tools\Annotations\IsReadOnly;
+
+#[IsReadOnly]
+#[Description('List all signatures for the current workspace.')]
+class ListSignaturesTool extends Tool
+{
+    public function handle(Request $request): ResponseFactory
+    {
+        $signatures = $request->user()->currentWorkspace->signatures()->latest()->get();
+
+        return Response::structured($signatures->toArray());
+    }
+}
diff --git a/app/Mcp/Tools/Signature/UpdateSignatureTool.php b/app/Mcp/Tools/Signature/UpdateSignatureTool.php
new file mode 100644
index 00000000..0747cf16
--- /dev/null
+++ b/app/Mcp/Tools/Signature/UpdateSignatureTool.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Mcp\Tools\Signature;
+
+use App\Actions\Signature\UpdateSignature;
+use App\Models\WorkspaceSignature;
+use Illuminate\Contracts\JsonSchema\JsonSchema;
+use Laravel\Mcp\Request;
+use Laravel\Mcp\Response;
+use Laravel\Mcp\ResponseFactory;
+use Laravel\Mcp\Server\Attributes\Description;
+use Laravel\Mcp\Server\Tool;
+
+#[Description('Update a signature name or content.')]
+class UpdateSignatureTool extends Tool
+{
+    public function handle(Request $request): Response|ResponseFactory
+    {
+        $validated = $request->validate([
+            'signature_id' => ['required', 'string'],
+            'name' => ['required', 'string', 'max:255'],
+            'content' => ['required', 'string'],
+        ]);
+
+        $signature = WorkspaceSignature::where('workspace_id', $request->user()->current_workspace_id)
+            ->find(data_get($validated, 'signature_id'));
+
+        if (! $signature) {
+            return Response::error('Signature not found.');
+        }
+
+        $signature = UpdateSignature::execute($signature, $validated);
+
+        return Response::structured($signature->toArray());
+    }
+
+    public function schema(JsonSchema $schema): array
+    {
+        return [
+            'signature_id' => $schema->string()->required()->description('The signature ID.'),
+            'name' => $schema->string()->required()->description('The new name.'),
+            'content' => $schema->string()->required()->description('The new content (hashtags, links, custom text).'),
+        ];
+    }
+}
diff --git a/app/Models/WorkspaceSignature.php b/app/Models/WorkspaceSignature.php
new file mode 100644
index 00000000..8437a1ec
--- /dev/null
+++ b/app/Models/WorkspaceSignature.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use Database\Factories\WorkspaceSignatureFactory;
+use Illuminate\Database\Eloquent\Concerns\HasUuids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class WorkspaceSignature extends Model
+{
+    /** @use HasFactory<WorkspaceSignatureFactory> */
+    use HasFactory, HasUuids, SoftDeletes;
+
+    protected $fillable = [
+        'workspace_id',
+        'name',
+        'content',
+    ];
+
+    public function workspace(): BelongsTo
+    {
+        return $this->belongsTo(Workspace::class);
+    }
+}
diff --git a/database/factories/WorkspaceSignatureFactory.php b/database/factories/WorkspaceSignatureFactory.php
new file mode 100644
index 00000000..9c2dd4e3
--- /dev/null
+++ b/database/factories/WorkspaceSignatureFactory.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Database\Factories;
+
+use App\Models\Workspace;
+use App\Models\WorkspaceSignature;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/**
+ * @extends Factory<WorkspaceSignature>
+ */
+class WorkspaceSignatureFactory extends Factory
+{
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        return [
+            'workspace_id' => Workspace::factory(),
+            'name' => fake()->words(2, true),
+            'content' => '#'.implode(' #', fake()->words(5)),
+        ];
+    }
+}
diff --git a/database/migrations/2026_01_17_152319_create_workspace_signatures_table.php b/database/migrations/2026_01_17_152319_create_workspace_signatures_table.php
new file mode 100644
index 00000000..75d5b4ee
--- /dev/null
+++ b/database/migrations/2026_01_17_152319_create_workspace_signatures_table.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('workspace_signatures', function (Blueprint $table) {
+            $table->uuid('id')->primary();
+            $table->foreignUuid('workspace_id')->constrained()->cascadeOnDelete();
+            $table->string('name');
+            $table->text('content');
+            $table->timestamps();
+            $table->softDeletes();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('workspace_signatures');
+    }
+};
diff --git a/lang/en/signatures.php b/lang/en/signatures.php
new file mode 100644
index 00000000..c03b3269
--- /dev/null
+++ b/lang/en/signatures.php
@@ -0,0 +1,54 @@
+<?php
+
+return [
+    'title' => 'Signatures',
+    'description' => 'Create reusable signatures to quickly append to your posts',
+    'search' => 'Search signatures...',
+    'new' => 'New signature',
+    'empty_title' => 'No signatures yet',
+    'empty_description' => 'Create signatures to quickly append hashtags, links, or any reusable text to your posts',
+    'no_search_results' => 'No signatures match your search',
+    'try_different_search' => 'Try a different keyword or clear the search.',
+    'table' => [
+        'name' => 'Name',
+        'content' => 'Content',
+        'created_at' => 'Created',
+    ],
+
+    'create' => [
+        'title' => 'Create signature',
+        'description' => 'Give your signature a name and the content to append (hashtags, links, custom text — anything you reuse).',
+        'name' => 'Name',
+        'name_placeholder' => 'e.g. Marketing, Travel, Brand sign-off',
+        'content' => 'Content',
+        'content_placeholder' => "#marketing #socialmedia\nLearn more: https://yourbrand.com",
+        'content_hint' => 'Hashtags, links, custom intros, signoffs — anything you append to posts.',
+        'submit' => 'Create signature',
+        'submitting' => 'Creating...',
+    ],
+
+    'edit' => [
+        'title' => 'Edit signature',
+        'description' => 'Update the name and content for this signature.',
+        'name' => 'Name',
+        'name_placeholder' => 'e.g. Marketing, Travel, Brand sign-off',
+        'content' => 'Content',
+        'content_placeholder' => "#marketing #socialmedia\nLearn more: https://yourbrand.com",
+        'content_hint' => 'Hashtags, links, custom intros, signoffs — anything you append to posts.',
+        'submit' => 'Save changes',
+        'submitting' => 'Saving...',
+    ],
+
+    'delete' => [
+        'title' => 'Delete signature',
+        'description' => 'Are you sure you want to delete this signature? This action cannot be undone.',
+        'confirm' => 'Delete',
+        'cancel' => 'Cancel',
+    ],
+
+    'flash' => [
+        'created' => 'Signature created.',
+        'updated' => 'Signature updated.',
+        'deleted' => 'Signature deleted.',
+    ],
+];
diff --git a/lang/es/signatures.php b/lang/es/signatures.php
new file mode 100644
index 00000000..099d7891
--- /dev/null
+++ b/lang/es/signatures.php
@@ -0,0 +1,54 @@
+<?php
+
+return [
+    'title' => 'Firmas',
+    'description' => 'Crea firmas reutilizables para añadir rápidamente a tus posts',
+    'search' => 'Buscar firmas...',
+    'new' => 'Nueva firma',
+    'empty_title' => 'Aún no hay firmas',
+    'empty_description' => 'Crea firmas para añadir hashtags, links o cualquier texto reutilizable a tus posts',
+    'no_search_results' => 'Ninguna firma coincide con tu búsqueda',
+    'try_different_search' => 'Prueba otra palabra clave o limpia la búsqueda.',
+    'table' => [
+        'name' => 'Nombre',
+        'content' => 'Contenido',
+        'created_at' => 'Creado',
+    ],
+
+    'create' => [
+        'title' => 'Crear firma',
+        'description' => 'Dale un nombre a tu firma y el contenido para añadir (hashtags, links, texto libre — lo que reutilizas).',
+        'name' => 'Nombre',
+        'name_placeholder' => 'ej: Marketing, Viaje, Cierre de marca',
+        'content' => 'Contenido',
+        'content_placeholder' => "#marketing #socialmedia\nMás info: https://tumarca.com",
+        'content_hint' => 'Hashtags, links, intros, cierres — cualquier cosa que añades a los posts.',
+        'submit' => 'Crear firma',
+        'submitting' => 'Creando...',
+    ],
+
+    'edit' => [
+        'title' => 'Editar firma',
+        'description' => 'Actualiza el nombre y el contenido de esta firma.',
+        'name' => 'Nombre',
+        'name_placeholder' => 'ej: Marketing, Viaje, Cierre de marca',
+        'content' => 'Contenido',
+        'content_placeholder' => "#marketing #socialmedia\nMás info: https://tumarca.com",
+        'content_hint' => 'Hashtags, links, intros, cierres — cualquier cosa que añades a los posts.',
+        'submit' => 'Guardar cambios',
+        'submitting' => 'Guardando...',
+    ],
+
+    'delete' => [
+        'title' => 'Eliminar firma',
+        'description' => '¿Seguro que quieres eliminar esta firma? Esta acción no se puede deshacer.',
+        'confirm' => 'Eliminar',
+        'cancel' => 'Cancelar',
+    ],
+
+    'flash' => [
+        'created' => 'Firma creada.',
+        'updated' => 'Firma actualizada.',
+        'deleted' => 'Firma eliminada.',
+    ],
+];
diff --git a/lang/pt-BR/signatures.php b/lang/pt-BR/signatures.php
new file mode 100644
index 00000000..f1d998da
--- /dev/null
+++ b/lang/pt-BR/signatures.php
@@ -0,0 +1,54 @@
+<?php
+
+return [
+    'title' => 'Assinaturas',
+    'description' => 'Crie assinaturas reutilizáveis pra anexar rapidamente nos seus posts',
+    'search' => 'Buscar assinaturas...',
+    'new' => 'Nova assinatura',
+    'empty_title' => 'Nenhuma assinatura ainda',
+    'empty_description' => 'Crie assinaturas pra anexar hashtags, links ou qualquer texto reutilizável nos seus posts',
+    'no_search_results' => 'Nenhuma assinatura corresponde à busca',
+    'try_different_search' => 'Tente outra palavra-chave ou limpe a busca.',
+    'table' => [
+        'name' => 'Nome',
+        'content' => 'Conteúdo',
+        'created_at' => 'Criado em',
+    ],
+
+    'create' => [
+        'title' => 'Criar assinatura',
+        'description' => 'Dê um nome à sua assinatura e o conteúdo pra anexar (hashtags, links, texto livre — o que você reutiliza).',
+        'name' => 'Nome',
+        'name_placeholder' => 'ex: Marketing, Viagem, Encerramento da marca',
+        'content' => 'Conteúdo',
+        'content_placeholder' => "#marketing #socialmedia\nSaiba mais: https://suamarca.com",
+        'content_hint' => 'Hashtags, links, intros, assinaturas — qualquer coisa que você anexa nos posts.',
+        'submit' => 'Criar assinatura',
+        'submitting' => 'Criando...',
+    ],
+
+    'edit' => [
+        'title' => 'Editar assinatura',
+        'description' => 'Atualize o nome e o conteúdo desta assinatura.',
+        'name' => 'Nome',
+        'name_placeholder' => 'ex: Marketing, Viagem, Encerramento da marca',
+        'content' => 'Conteúdo',
+        'content_placeholder' => "#marketing #socialmedia\nSaiba mais: https://suamarca.com",
+        'content_hint' => 'Hashtags, links, intros, assinaturas — qualquer coisa que você anexa nos posts.',
+        'submit' => 'Salvar alterações',
+        'submitting' => 'Salvando...',
+    ],
+
+    'delete' => [
+        'title' => 'Deletar assinatura',
+        'description' => 'Tem certeza que quer deletar esta assinatura? Esta ação não pode ser desfeita.',
+        'confirm' => 'Deletar',
+        'cancel' => 'Cancelar',
+    ],
+
+    'flash' => [
+        'created' => 'Assinatura criada.',
+        'updated' => 'Assinatura atualizada.',
+        'deleted' => 'Assinatura deletada.',
+    ],
+];
diff --git a/resources/js/components/posts/SignaturesModal.vue b/resources/js/components/posts/SignaturesModal.vue
new file mode 100644
index 00000000..9c6fa34a
--- /dev/null
+++ b/resources/js/components/posts/SignaturesModal.vue
@@ -0,0 +1,68 @@
+<script setup lang="ts">
+import { ref } from 'vue';
+
+import {
+    CommandDialog,
+    CommandEmpty,
+    CommandGroup,
+    CommandInput,
+    CommandItem,
+    CommandList,
+} from '@/components/ui/command';
+
+interface Signature {
+    id: string;
+    name: string;
+    content: string;
+}
+
+defineProps<{
+    signatures: Signature[];
+}>();
+
+const emit = defineEmits<{
+    (e: 'select', signature: Signature): void;
+}>();
+
+const isOpen = ref(false);
+
+const handleSelect = (signature: Signature) => {
+    emit('select', signature);
+    isOpen.value = false;
+};
+
+const open = () => {
+    isOpen.value = true;
+};
+
+const close = () => {
+    isOpen.value = false;
+};
+
+defineExpose({
+    open,
+    close,
+});
+</script>
+
+<template>
+    <CommandDialog v-model:open="isOpen">
+        <CommandInput :placeholder="$t('posts.edit.signatures_modal.search')" />
+        <CommandList>
+            <CommandEmpty>
+                {{ $t('posts.edit.signatures_modal.no_results') }}
+            </CommandEmpty>
+            <CommandGroup>
+                <CommandItem v-for="signature in signatures" :key="signature.id" :value="signature.name"
+                    class="flex flex-col items-start gap-1 py-3" @select="handleSelect(signature)">
+                    <div class="font-medium text-sm">
+                        {{ signature.name }}
+                    </div>
+                    <p class="text-xs  line-clamp-2 w-full">
+                        {{ signature.content }}
+                    </p>
+                </CommandItem>
+            </CommandGroup>
+        </CommandList>
+    </CommandDialog>
+</template>
diff --git a/resources/js/components/signatures/CreateDialog.vue b/resources/js/components/signatures/CreateDialog.vue
new file mode 100644
index 00000000..5396423b
--- /dev/null
+++ b/resources/js/components/signatures/CreateDialog.vue
@@ -0,0 +1,95 @@
+<script setup lang="ts">
+import { useForm } from '@inertiajs/vue3';
+import { trans } from 'laravel-vue-i18n';
+
+import { Button } from '@/components/ui/button';
+import {
+    Dialog,
+    DialogContent,
+    DialogDescription,
+    DialogFooter,
+    DialogHeader,
+    DialogTitle,
+} from '@/components/ui/dialog';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import { Textarea } from '@/components/ui/textarea';
+import { store as signaturesStore } from '@/routes/app/signatures';
+
+const open = defineModel<boolean>('open', { default: false });
+
+const form = useForm({
+    name: '',
+    content: '',
+});
+
+const submit = () => {
+    form.post(signaturesStore.url(), {
+        onSuccess: () => {
+            open.value = false;
+            form.reset();
+        },
+    });
+};
+
+const handleOpenChange = (value: boolean) => {
+    if (value) {
+        form.reset();
+        form.clearErrors();
+    }
+    open.value = value;
+};
+</script>
+
+<template>
+    <Dialog :open="open" @update:open="handleOpenChange">
+        <DialogContent class="sm:max-w-md">
+            <DialogHeader>
+                <DialogTitle>{{ $t('signatures.create.title') }}</DialogTitle>
+                <DialogDescription>
+                    {{ $t('signatures.create.description') }}
+                </DialogDescription>
+            </DialogHeader>
+            <form @submit.prevent="submit" class="space-y-4">
+                <div class="grid gap-2">
+                    <Label for="create-name">{{ $t('signatures.create.name') }}</Label>
+                    <Input
+                        id="create-name"
+                        v-model="form.name"
+                        :placeholder="trans('signatures.create.name_placeholder')"
+                        :class="{ 'border-destructive': form.errors.name }"
+                    />
+                    <p v-if="form.errors.name" class="text-sm text-destructive">
+                        {{ form.errors.name }}
+                    </p>
+                </div>
+
+                <div class="grid gap-2">
+                    <Label for="create-content">{{ $t('signatures.create.content') }}</Label>
+                    <Textarea
+                        id="create-content"
+                        v-model="form.content"
+                        :placeholder="trans('signatures.create.content_placeholder')"
+                        rows="4"
+                        :class="{ 'border-destructive': form.errors.content }"
+                    />
+                    <p class="text-sm text-muted-foreground">
+                        {{ $t('signatures.create.content_hint') }}
+                    </p>
+                    <p v-if="form.errors.content" class="text-sm text-destructive">
+                        {{ form.errors.content }}
+                    </p>
+                </div>
+
+                <DialogFooter>
+                    <Button type="submit" :disabled="form.processing">
+                        {{ form.processing ? $t('signatures.create.submitting') : $t('signatures.create.submit') }}
+                    </Button>
+                    <Button type="button" variant="outline" @click="open = false">
+                        {{ $t('common.cancel') }}
+                    </Button>
+                </DialogFooter>
+            </form>
+        </DialogContent>
+    </Dialog>
+</template>
diff --git a/resources/js/components/signatures/EditDialog.vue b/resources/js/components/signatures/EditDialog.vue
new file mode 100644
index 00000000..9f566a65
--- /dev/null
+++ b/resources/js/components/signatures/EditDialog.vue
@@ -0,0 +1,106 @@
+<script setup lang="ts">
+import { useForm } from '@inertiajs/vue3';
+import { trans } from 'laravel-vue-i18n';
+import { watch } from 'vue';
+
+import { Button } from '@/components/ui/button';
+import {
+    Dialog,
+    DialogContent,
+    DialogDescription,
+    DialogFooter,
+    DialogHeader,
+    DialogTitle,
+} from '@/components/ui/dialog';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import { Textarea } from '@/components/ui/textarea';
+import { update as signaturesUpdate } from '@/routes/app/signatures';
+
+interface Signature {
+    id: string;
+    name: string;
+    content: string;
+}
+
+const props = defineProps<{
+    signature: Signature | null;
+}>();
+
+const open = defineModel<boolean>('open', { default: false });
+
+const form = useForm({
+    name: '',
+    content: '',
+});
+
+watch(() => props.signature, (signature) => {
+    if (signature) {
+        form.name = signature.name;
+        form.content = signature.content;
+        form.clearErrors();
+    }
+}, { immediate: true });
+
+const submit = () => {
+    if (!props.signature) return;
+    form.put(signaturesUpdate.url(props.signature.id), {
+        onSuccess: () => {
+            open.value = false;
+        },
+    });
+};
+</script>
+
+<template>
+    <Dialog v-model:open="open">
+        <DialogContent class="sm:max-w-md">
+            <DialogHeader>
+                <DialogTitle>{{ $t('signatures.edit.title') }}</DialogTitle>
+                <DialogDescription>
+                    {{ $t('signatures.edit.description') }}
+                </DialogDescription>
+            </DialogHeader>
+            <form @submit.prevent="submit" class="space-y-4">
+                <div class="grid gap-2">
+                    <Label for="edit-name">{{ $t('signatures.edit.name') }}</Label>
+                    <Input
+                        id="edit-name"
+                        v-model="form.name"
+                        :placeholder="trans('signatures.edit.name_placeholder')"
+                        :class="{ 'border-destructive': form.errors.name }"
+                    />
+                    <p v-if="form.errors.name" class="text-sm text-destructive">
+                        {{ form.errors.name }}
+                    </p>
+                </div>
+
+                <div class="grid gap-2">
+                    <Label for="edit-content">{{ $t('signatures.edit.content') }}</Label>
+                    <Textarea
+                        id="edit-content"
+                        v-model="form.content"
+                        :placeholder="trans('signatures.edit.content_placeholder')"
+                        rows="4"
+                        :class="{ 'border-destructive': form.errors.content }"
+                    />
+                    <p class="text-sm text-muted-foreground">
+                        {{ $t('signatures.edit.content_hint') }}
+                    </p>
+                    <p v-if="form.errors.content" class="text-sm text-destructive">
+                        {{ form.errors.content }}
+                    </p>
+                </div>
+
+                <DialogFooter>
+                    <Button type="submit" :disabled="form.processing">
+                        {{ form.processing ? $t('signatures.edit.submitting') : $t('signatures.edit.submit') }}
+                    </Button>
+                    <Button type="button" variant="outline" @click="open = false">
+                        {{ $t('common.cancel') }}
+                    </Button>
+                </DialogFooter>
+            </form>
+        </DialogContent>
+    </Dialog>
+</template>
diff --git a/resources/js/pages/signatures/Index.vue b/resources/js/pages/signatures/Index.vue
new file mode 100644
index 00000000..c6d95845
--- /dev/null
+++ b/resources/js/pages/signatures/Index.vue
@@ -0,0 +1,181 @@
+<script setup lang="ts">
+import { Head, InfiniteScroll, router } from '@inertiajs/vue3';
+import { IconHash, IconPencil, IconSearch, IconTrash } from '@tabler/icons-vue';
+import { trans } from 'laravel-vue-i18n';
+import { computed, ref, watch } from 'vue';
+
+import ConfirmDeleteModal from '@/components/ConfirmDeleteModal.vue';
+import EmptyState from '@/components/EmptyState.vue';
+import PageHeader from '@/components/PageHeader.vue';
+import CreateDialog from '@/components/signatures/CreateDialog.vue';
+import EditDialog from '@/components/signatures/EditDialog.vue';
+import { Button } from '@/components/ui/button';
+import { Input } from '@/components/ui/input';
+import {
+    Table,
+    TableBody,
+    TableCell,
+    TableHead,
+    TableHeader,
+    TableLoadMore,
+    TableRow,
+} from '@/components/ui/table';
+import dayjs from '@/dayjs';
+import debounce from '@/debounce';
+import AppLayout from '@/layouts/AppLayout.vue';
+import { destroy as signaturesDestroy, index as signaturesIndex } from '@/routes/app/signatures';
+import type { BreadcrumbItem } from '@/types';
+
+interface Workspace {
+    id: string;
+    name: string;
+}
+
+interface Signature {
+    id: string;
+    name: string;
+    content: string;
+    created_at: string;
+}
+
+interface ScrollSignatures {
+    data: Signature[];
+    meta: { hasNextPage: boolean };
+}
+
+interface Props {
+    workspace: Workspace;
+    signatures: ScrollSignatures;
+    filters: { search: string };
+}
+
+const props = defineProps<Props>();
+
+const searchQuery = ref(props.filters.search);
+
+const search = debounce(() => {
+    router.get(
+        signaturesIndex.url(),
+        { search: searchQuery.value || undefined },
+        { preserveState: true, preserveScroll: true, reset: ['signatures'] },
+    );
+}, 300);
+
+watch(searchQuery, () => search());
+
+const breadcrumbs = computed<BreadcrumbItem[]>(() => [
+    { title: trans('signatures.title') },
+]);
+
+const deleteModal = ref<InstanceType<typeof ConfirmDeleteModal> | null>(null);
+const isCreateDialogOpen = ref(false);
+const isEditDialogOpen = ref(false);
+const editingSignature = ref<Signature | null>(null);
+
+const openEditDialog = (signature: Signature) => {
+    editingSignature.value = signature;
+    isEditDialogOpen.value = true;
+};
+
+const handleDelete = (signatureId: string) => {
+    deleteModal.value?.open({ url: signaturesDestroy.url(signatureId) });
+};
+
+const formatDate = (date: string): string => dayjs.utc(date).local().format('D MMM YYYY');
+
+const hasActiveSearch = computed(() => Boolean(searchQuery.value?.trim()));
+</script>
+
+<template>
+    <Head :title="$t('signatures.title')" />
+
+    <AppLayout :breadcrumbs="breadcrumbs">
+        <div class="flex h-full flex-1 flex-col gap-4 p-4">
+            <PageHeader :title="$t('signatures.title')" />
+
+            <div class="flex items-center justify-between gap-3">
+                <div class="relative">
+                    <IconSearch class="pointer-events-none absolute left-3 top-1/2 size-4 -translate-y-1/2 text-muted-foreground" />
+                    <Input
+                        v-model="searchQuery"
+                        :placeholder="trans('signatures.search')"
+                        class="w-64 pl-9"
+                    />
+                </div>
+
+                <Button @click="isCreateDialogOpen = true">{{ $t('signatures.new') }}</Button>
+            </div>
+
+            <EmptyState
+                v-if="signatures.data.length === 0"
+                :icon="IconHash"
+                :title="hasActiveSearch ? $t('signatures.no_search_results') : $t('signatures.empty_title')"
+                :description="hasActiveSearch ? $t('signatures.try_different_search') : $t('signatures.empty_description')"
+            />
+
+            <div v-else class="rounded-md border">
+                <InfiniteScroll data="signatures" items-element="#signatures-body" preserve-url>
+                    <Table>
+                        <TableHeader>
+                            <TableRow>
+                                <TableHead>{{ $t('signatures.table.name') }}</TableHead>
+                                <TableHead>{{ $t('signatures.table.content') }}</TableHead>
+                                <TableHead>{{ $t('signatures.table.created_at') }}</TableHead>
+                                <TableHead class="text-right" />
+                            </TableRow>
+                        </TableHeader>
+                        <TableBody id="signatures-body">
+                            <TableRow
+                                v-for="signature in signatures.data"
+                                :key="signature.id"
+                                class="cursor-pointer"
+                                @click="openEditDialog(signature)"
+                            >
+                                <TableCell class="font-medium">{{ signature.name }}</TableCell>
+                                <TableCell class="max-w-md">
+                                    <p class="truncate text-sm text-muted-foreground">{{ signature.content }}</p>
+                                </TableCell>
+                                <TableCell class="text-muted-foreground">{{ formatDate(signature.created_at) }}</TableCell>
+                                <TableCell class="text-right" @click.stop>
+                                    <div class="flex justify-end gap-1">
+                                        <Button
+                                            variant="ghost"
+                                            size="icon"
+                                            class="size-8"
+                                            @click="openEditDialog(signature)"
+                                        >
+                                            <IconPencil class="h-4 w-4" />
+                                        </Button>
+                                        <Button
+                                            variant="ghost"
+                                            size="icon"
+                                            class="size-8 text-muted-foreground hover:bg-destructive/10 hover:text-destructive"
+                                            @click="handleDelete(signature.id)"
+                                        >
+                                            <IconTrash class="h-4 w-4" />
+                                        </Button>
+                                    </div>
+                                </TableCell>
+                            </TableRow>
+                        </TableBody>
+                    </Table>
+
+                    <template #next="{ loading }">
+                        <TableLoadMore v-if="loading" />
+                    </template>
+                </InfiniteScroll>
+            </div>
+        </div>
+    </AppLayout>
+
+    <CreateDialog v-model:open="isCreateDialogOpen" />
+    <EditDialog v-model:open="isEditDialogOpen" :signature="editingSignature" />
+
+    <ConfirmDeleteModal
+        ref="deleteModal"
+        :title="$t('signatures.delete.title')"
+        :description="$t('signatures.delete.description')"
+        :action="$t('signatures.delete.confirm')"
+        :cancel="$t('signatures.delete.cancel')"
+    />
+</template>
diff --git a/tests/Feature/Api/SignatureApiTest.php b/tests/Feature/Api/SignatureApiTest.php
new file mode 100644
index 00000000..b390518c
--- /dev/null
+++ b/tests/Feature/Api/SignatureApiTest.php
@@ -0,0 +1,195 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Models\ApiToken;
+use App\Models\Workspace;
+use App\Models\WorkspaceSignature;
+use Illuminate\Support\Facades\Hash;
+use Illuminate\Support\Str;
+
+/**
+ * @return array{token: ApiToken, plain_token: string, workspace: Workspace}
+ */
+function createSignatureApiToken(array $overrides = []): array
+{
+    $plainToken = 'tp_'.Str::random(48);
+
+    $workspace = data_get($overrides, 'workspace') ?? Workspace::factory()->create();
+
+    $factoryOverrides = collect($overrides)->except('workspace')->toArray();
+
+    $apiToken = ApiToken::factory()->create(array_merge([
+        'workspace_id' => $workspace->id,
+        'token_lookup' => substr($plainToken, 3, 16),
+        'token_hash' => Hash::make($plainToken),
+    ], $factoryOverrides));
+
+    return [
+        'token' => $apiToken,
+        'plain_token' => $plainToken,
+        'workspace' => $workspace,
+    ];
+}
+
+test('list signatures', function () {
+    $result = createSignatureApiToken();
+
+    WorkspaceSignature::factory()->count(3)->create([
+        'workspace_id' => $result['workspace']->id,
+    ]);
+
+    $response = $this->withHeaders([
+        'Authorization' => 'Bearer '.$result['plain_token'],
+    ])->getJson(
+        route('api.signatures.index'),
+        ['HTTP_HOST' => 'api.trypost.test']
+    );
+
+    $response->assertOk();
+    $response->assertJsonCount(3);
+});
+
+test('create signature', function () {
+    $result = createSignatureApiToken();
+
+    $response = $this->withHeaders([
+        'Authorization' => 'Bearer '.$result['plain_token'],
+    ])->postJson(
+        route('api.signatures.store'),
+        [
+            'name' => 'Marketing Tags',
+            'content' => '#marketing #growth #saas',
+        ],
+        ['HTTP_HOST' => 'api.trypost.test']
+    );
+
+    $response->assertCreated();
+    $response->assertJsonPath('name', 'Marketing Tags');
+
+    expect($result['workspace']->signatures()->count())->toBe(1);
+});
+
+test('create signature validation errors', function () {
+    $result = createSignatureApiToken();
+
+    $response = $this->withHeaders([
+        'Authorization' => 'Bearer '.$result['plain_token'],
+    ])->postJson(
+        route('api.signatures.store'),
+        [],
+        ['HTTP_HOST' => 'api.trypost.test']
+    );
+
+    $response->assertUnprocessable();
+    $response->assertJsonValidationErrors(['name', 'content']);
+});
+
+test('update signature', function () {
+    $result = createSignatureApiToken();
+
+    $signature = WorkspaceSignature::factory()->create([
+        'workspace_id' => $result['workspace']->id,
+        'name' => 'Old Name',
+    ]);
+
+    $response = $this->withHeaders([
+        'Authorization' => 'Bearer '.$result['plain_token'],
+    ])->putJson(
+        route('api.signatures.update', $signature),
+        [
+            'name' => 'Updated Name',
+            'content' => '#updated #tags',
+        ],
+        ['HTTP_HOST' => 'api.trypost.test']
+    );
+
+    $response->assertOk();
+    $response->assertJsonPath('name', 'Updated Name');
+});
+
+test('delete signature', function () {
+    $result = createSignatureApiToken();
+
+    $signature = WorkspaceSignature::factory()->create([
+        'workspace_id' => $result['workspace']->id,
+    ]);
+
+    $response = $this->withHeaders([
+        'Authorization' => 'Bearer '.$result['plain_token'],
+    ])->deleteJson(
+        route('api.signatures.destroy', $signature),
+        [],
+        ['HTTP_HOST' => 'api.trypost.test']
+    );
+
+    $response->assertNoContent();
+
+    expect(WorkspaceSignature::find($signature->id))->toBeNull();
+});
+
+test('cannot access signatures from another workspace', function () {
+    $result = createSignatureApiToken();
+
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create([
+        'workspace_id' => $otherWorkspace->id,
+    ]);
+
+    $response = $this->withHeaders([
+        'Authorization' => 'Bearer '.$result['plain_token'],
+    ])->putJson(
+        route('api.signatures.update', $signature),
+        [
+            'name' => 'Hacked Name',
+            'content' => '#hacked',
+        ],
+        ['HTTP_HOST' => 'api.trypost.test']
+    );
+
+    $response->assertNotFound();
+});
+
+test('cannot update signature from another workspace', function () {
+    $result = createSignatureApiToken();
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $otherWorkspace->id]);
+
+    $this->withHeaders(['Authorization' => 'Bearer '.data_get($result, 'plain_token')])
+        ->putJson(route('api.signatures.update', $signature), [
+            'name' => 'Hacked',
+            'content' => '#hacked',
+        ])
+        ->assertNotFound();
+});
+
+test('update signature validation errors', function () {
+    $result = createSignatureApiToken();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => data_get($result, 'workspace')->id]);
+
+    $this->withHeaders(['Authorization' => 'Bearer '.data_get($result, 'plain_token')])
+        ->putJson(route('api.signatures.update', $signature), [])
+        ->assertUnprocessable();
+});
+
+test('list signatures returns correct structure', function () {
+    $result = createSignatureApiToken();
+    WorkspaceSignature::factory()->create(['workspace_id' => data_get($result, 'workspace')->id]);
+
+    $this->withHeaders(['Authorization' => 'Bearer '.data_get($result, 'plain_token')])
+        ->getJson(route('api.signatures.index'))
+        ->assertOk()
+        ->assertJsonStructure([
+            '*' => ['id', 'name', 'content', 'created_at', 'updated_at'],
+        ]);
+});
+
+test('cannot delete signature from another workspace', function () {
+    $result = createSignatureApiToken();
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $otherWorkspace->id]);
+
+    $this->withHeaders(['Authorization' => 'Bearer '.data_get($result, 'plain_token')])
+        ->deleteJson(route('api.signatures.destroy', $signature))
+        ->assertNotFound();
+});
diff --git a/tests/Feature/Mcp/SignatureToolTest.php b/tests/Feature/Mcp/SignatureToolTest.php
new file mode 100644
index 00000000..f33b69d9
--- /dev/null
+++ b/tests/Feature/Mcp/SignatureToolTest.php
@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Enums\UserWorkspace\Role;
+use App\Mcp\Servers\TryPostServer;
+use App\Mcp\Tools\Signature\CreateSignatureTool;
+use App\Mcp\Tools\Signature\DeleteSignatureTool;
+use App\Mcp\Tools\Signature\ListSignaturesTool;
+use App\Mcp\Tools\Signature\UpdateSignatureTool;
+use App\Models\User;
+use App\Models\Workspace;
+use App\Models\WorkspaceSignature;
+
+beforeEach(function () {
+    $this->user = User::factory()->create();
+    $this->workspace = Workspace::factory()->create(['user_id' => $this->user->id]);
+    $this->workspace->members()->attach($this->user->id, ['role' => Role::Member->value]);
+    $this->user->update(['current_workspace_id' => $this->workspace->id]);
+});
+
+test('can list signatures', function () {
+    WorkspaceSignature::factory()->count(2)->create(['workspace_id' => $this->workspace->id]);
+
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(ListSignaturesTool::class, []);
+
+    $response->assertOk();
+});
+
+test('can create signature', function () {
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(CreateSignatureTool::class, [
+            'name' => 'Marketing',
+            'content' => '#marketing #social',
+        ]);
+
+    $response->assertOk();
+    $response->assertSee('Marketing');
+    expect($this->workspace->signatures()->count())->toBe(1);
+});
+
+test('create signature validates required fields', function () {
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(CreateSignatureTool::class, []);
+
+    $response->assertHasErrors();
+});
+
+test('can update signature', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(UpdateSignatureTool::class, [
+            'signature_id' => $signature->id,
+            'name' => 'Updated',
+            'content' => '#updated',
+        ]);
+
+    $response->assertOk();
+    $response->assertSee('Updated');
+});
+
+test('cannot update signature from another workspace', function () {
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $otherWorkspace->id]);
+
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(UpdateSignatureTool::class, [
+            'signature_id' => $signature->id,
+            'name' => 'Hacked',
+            'content' => '#hacked',
+        ]);
+
+    $response->assertHasErrors(['Signature not found.']);
+});
+
+test('can delete signature', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(DeleteSignatureTool::class, ['signature_id' => $signature->id]);
+
+    $response->assertOk();
+    expect(WorkspaceSignature::find($signature->id))->toBeNull();
+});
+
+test('cannot delete signature from another workspace', function () {
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $otherWorkspace->id]);
+
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(DeleteSignatureTool::class, ['signature_id' => $signature->id]);
+
+    $response->assertHasErrors(['Signature not found.']);
+});
+
+test('update signature validates required fields', function () {
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(UpdateSignatureTool::class, []);
+
+    $response->assertHasErrors();
+});
+
+test('delete signature validates signature_id required', function () {
+    $response = TryPostServer::actingAs($this->user)
+        ->tool(DeleteSignatureTool::class, []);
+
+    $response->assertHasErrors();
+});
diff --git a/tests/Feature/WorkspaceSignatureControllerTest.php b/tests/Feature/WorkspaceSignatureControllerTest.php
new file mode 100644
index 00000000..7c9502c8
--- /dev/null
+++ b/tests/Feature/WorkspaceSignatureControllerTest.php
@@ -0,0 +1,193 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Enums\UserWorkspace\Role;
+use App\Models\User;
+use App\Models\Workspace;
+use App\Models\WorkspaceSignature;
+
+beforeEach(function () {
+    $this->user = User::factory()->create([]);
+    $this->workspace = Workspace::factory()->create(['user_id' => $this->user->id]);
+    $this->workspace->members()->attach($this->user->id, ['role' => Role::Member->value]);
+    $this->user->update(['current_workspace_id' => $this->workspace->id]);
+});
+
+// Index tests
+test('signatures index requires authentication', function () {
+    $response = $this->get(route('app.signatures.index'));
+
+    $response->assertRedirect(route('login'));
+});
+
+test('signatures index shows signatures for workspace', function () {
+    WorkspaceSignature::factory()->count(3)->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->actingAs($this->user)->get(route('app.signatures.index'));
+
+    $response->assertOk();
+    $response->assertInertia(fn ($page) => $page
+        ->component('signatures/Index', false)
+        ->has('workspace')
+        ->has('signatures.data', 3)
+    );
+});
+
+test('signatures index redirects if no workspace', function () {
+    $this->user->update(['current_workspace_id' => null]);
+
+    $response = $this->actingAs($this->user)->get(route('app.signatures.index'));
+
+    $response->assertRedirect(route('app.workspaces.create'));
+});
+
+// Store tests
+test('store signature requires authentication', function () {
+    $response = $this->post(route('app.signatures.store'), [
+        'name' => 'Marketing',
+        'content' => '#marketing #digital #growth',
+    ]);
+
+    $response->assertRedirect(route('login'));
+});
+
+test('store signature creates signature', function () {
+    $response = $this->actingAs($this->user)->post(route('app.signatures.store'), [
+        'name' => 'Marketing',
+        'content' => '#marketing #digital #growth',
+    ]);
+
+    $response->assertRedirect(route('app.signatures.index'));
+
+    $this->assertDatabaseHas('workspace_signatures', [
+        'workspace_id' => $this->workspace->id,
+        'name' => 'Marketing',
+        'content' => '#marketing #digital #growth',
+    ]);
+});
+
+test('store signature validates required fields', function () {
+    $response = $this->actingAs($this->user)->post(route('app.signatures.store'), [
+        'name' => '',
+        'content' => '',
+    ]);
+
+    $response->assertSessionHasErrors(['name', 'content']);
+});
+
+// Update tests
+test('update signature requires authentication', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->put(route('app.signatures.update', $signature), [
+        'name' => 'Updated Name',
+        'content' => '#updated #content',
+    ]);
+
+    $response->assertRedirect(route('login'));
+});
+
+test('update signature updates the signature', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->actingAs($this->user)->put(route('app.signatures.update', $signature), [
+        'name' => 'Updated Name',
+        'content' => '#updated #content',
+    ]);
+
+    $response->assertRedirect(route('app.signatures.index'));
+
+    $signature->refresh();
+    expect($signature->name)->toBe('Updated Name');
+    expect($signature->content)->toBe('#updated #content');
+});
+
+test('update signature returns 404 for other workspace signature', function () {
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $otherWorkspace->id]);
+
+    $response = $this->actingAs($this->user)->put(route('app.signatures.update', $signature), [
+        'name' => 'Updated Name',
+        'content' => '#updated #content',
+    ]);
+
+    $response->assertNotFound();
+});
+
+// Destroy tests
+test('destroy signature requires authentication', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->delete(route('app.signatures.destroy', $signature));
+
+    $response->assertRedirect(route('login'));
+});
+
+test('destroy signature deletes the signature', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->actingAs($this->user)->delete(route('app.signatures.destroy', $signature));
+
+    $response->assertRedirect(route('app.signatures.index'));
+    expect(WorkspaceSignature::find($signature->id))->toBeNull();
+});
+
+test('destroy signature returns 404 for other workspace signature', function () {
+    $otherWorkspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $otherWorkspace->id]);
+
+    $response = $this->actingAs($this->user)->delete(route('app.signatures.destroy', $signature));
+
+    $response->assertNotFound();
+});
+
+test('signatures index filters by search query', function () {
+    WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id, 'name' => 'Marketing']);
+    WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id, 'name' => 'Travel']);
+    WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id, 'name' => 'Food']);
+
+    $response = $this->actingAs($this->user)->get(route('app.signatures.index', ['search' => 'market']));
+
+    $response->assertOk();
+    $response->assertInertia(fn ($page) => $page
+        ->has('signatures.data', 1)
+        ->has('filters')
+        ->where('filters.search', 'market')
+    );
+});
+
+test('signatures index returns all when no search query', function () {
+    WorkspaceSignature::factory()->count(3)->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->actingAs($this->user)->get(route('app.signatures.index'));
+
+    $response->assertOk();
+    $response->assertInertia(fn ($page) => $page
+        ->has('signatures.data', 3)
+        ->where('filters.search', '')
+    );
+});
+
+// Member authorization tests
+test('member can create signature', function () {
+    $member = User::factory()->create(['account_id' => $this->workspace->account_id]);
+    $this->workspace->members()->attach($member->id, ['role' => Role::Member->value]);
+    $member->update(['current_workspace_id' => $this->workspace->id]);
+
+    $response = $this->actingAs($member)->post(route('app.signatures.store'), [
+        'name' => 'Test Signature',
+        'content' => '#test #signature',
+    ]);
+
+    $response->assertRedirect();
+    expect($this->workspace->signatures()->count())->toBe(1);
+});
+
+test('update signature validates required fields', function () {
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $this->workspace->id]);
+
+    $response = $this->actingAs($this->user)->put(route('app.signatures.update', $signature), []);
+
+    $response->assertSessionHasErrors(['name', 'content']);
+});
diff --git a/tests/Unit/Models/WorkspaceSignatureTest.php b/tests/Unit/Models/WorkspaceSignatureTest.php
new file mode 100644
index 00000000..e40f26b8
--- /dev/null
+++ b/tests/Unit/Models/WorkspaceSignatureTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Models\Workspace;
+use App\Models\WorkspaceSignature;
+
+test('workspace signature belongs to workspace', function () {
+    $workspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create(['workspace_id' => $workspace->id]);
+
+    expect($signature->workspace->id)->toBe($workspace->id);
+});
+
+test('workspace signature has fillable attributes', function () {
+    $workspace = Workspace::factory()->create();
+    $signature = WorkspaceSignature::factory()->create([
+        'workspace_id' => $workspace->id,
+        'name' => 'Marketing',
+        'content' => '#marketing #digital #social',
+    ]);
+
+    expect($signature->name)->toBe('Marketing');
+    expect($signature->content)->toBe('#marketing #digital #social');
+});
+
+test('workspace signature uses soft deletes', function () {
+    $signature = WorkspaceSignature::factory()->create();
+    $signatureId = $signature->id;
+
+    $signature->delete();
+
+    expect(WorkspaceSignature::find($signatureId))->toBeNull();
+    expect(WorkspaceSignature::withTrashed()->find($signatureId))->not->toBeNull();
+});