diff --git a/.phase41-state.json b/.phase41-state.json
index 15ad2fb..c677016 100644
--- a/.phase41-state.json
+++ b/.phase41-state.json
@@ -1,8 +1,9 @@
 {
   "completed_features": [],
-  "current_feature": "stat-card-component",
+  "current_feature": "toolbar-button-component",
   "started_at": "2026-05-23T10:23:26.274445",
   "attempted_features": [
-    "page-header-component"
+    "page-header-component",
+    "stat-card-component"
   ]
 }
\ No newline at end of file
diff --git a/GENERATION_LOG.md b/GENERATION_LOG.md
index 401d2a0..143f297 100644
--- a/GENERATION_LOG.md
+++ b/GENERATION_LOG.md
@@ -4308,3 +4308,21 @@ src/index.ts(27,25): error TS2769: No overload matches this call.
   Overload 1 of 3, '(plugin: FastifyPluginCallback<{ limits: { fileSize: number; }; }, RawServerDefault, FastifyTypeProvider, FastifyBaseLogger>, opts?: FastifyRegisterOptions<...> | undefined): FastifyInstance<...> & PromiseLike<...>', gave the following error.
     Argument of type 'Promise<FastifyMultipartPlugin>' is not assignable to parameter of type 'FastifyPluginCallback<{ limits: { fileSize: number; }; }, RawServerDefault, FastifyTypeProvider, FastifyBaseLogger>'.
       Type 'Promise<FastifyMultipartPlugin>' provides no match for the signature '(instance: FastifyInstance<RawServerDefault, IncomingMessage, ServerResponse<IncomingMessage>, 
+- `10:23:51` **INFO**   Committed feature stat-card-component
+- `10:23:51` **INFO**   Pushed: rc=0
+
+## Phase-3 Feature: toolbar-button-component (2026-05-23 10:23:51)
+
+- `10:23:51` **INFO** Description: ToolbarButton mit Tooltip + Icon
+- `10:23:51` **INFO**   Generating apps/web/src/components/ToolbarButton.tsx (ToolbarButton-Component. Props: icon (ReactNode), label, onClick, acti…)
+- `10:24:00` **INFO**     wrote 959 chars in 9.0s (attempt 1)
+- `10:24:00` **INFO** Running tsc --noEmit on api…
+- `10:24:02` **WARN**   tsc errors:
+src/db/schema.ts(37,14): error TS7022: 'customers' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.
+src/db/schema.ts(45,59): error TS7024: Function implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.
+src/db/schema.ts(49,14): error TS7022: 'projects' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.
+src/db/schema.ts(53,56): error TS7024: Function implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.
+src/index.ts(27,25): error TS2769: No overload matches this call.
+  Overload 1 of 3, '(plugin: FastifyPluginCallback<{ limits: { fileSize: number; }; }, RawServerDefault, FastifyTypeProvider, FastifyBaseLogger>, opts?: FastifyRegisterOptions<...> | undefined): FastifyInstance<...> & PromiseLike<...>', gave the following error.
+    Argument of type 'Promise<FastifyMultipartPlugin>' is not assignable to parameter of type 'FastifyPluginCallback<{ limits: { fileSize: number; }; }, RawServerDefault, FastifyTypeProvider, FastifyBaseLogger>'.
+      Type 'Promise<FastifyMultipartPlugin>' provides no match for the signature '(instance: FastifyInstance<RawServerDefault, IncomingMessage, ServerResponse<IncomingMessage>, 
diff --git a/apps/web/src/components/ToolbarButton.tsx b/apps/web/src/components/ToolbarButton.tsx
new file mode 100644
index 0000000..399269a
--- /dev/null
+++ b/apps/web/src/components/ToolbarButton.tsx
@@ -0,0 +1,38 @@
+import React from 'react';
+
+interface ToolbarButtonProps {
+  icon: React.ReactNode;
+  label: string;
+  onClick: () => void;
+  active?: boolean;
+  disabled?: boolean;
+}
+
+export default function ToolbarButton({
+  icon,
+  label,
+  onClick,
+  active = false,
+  disabled = false,
+}: ToolbarButtonProps) {
+  return (
+    <button
+      onClick={onClick}
+      disabled={disabled}
+      title={label}
+      className={`
+        relative flex items-center justify-center w-10 h-10 rounded-md transition-all duration-200
+        ${disabled 
+          ? 'opacity-50 cursor-not-allowed bg-gray-100 text-gray-400' 
+          : active 
+            ? 'bg-blue-100 text-blue-600 ring-2 ring-blue-500 ring-inset' 
+            : 'bg-white text-gray-600 hover:bg-gray-100 hover:text-gray-900 border border-gray-200 shadow-sm'
+        }
+      `}
+    >
+      <span className="flex items-center justify-center pointer-events-none">
+        {icon}
+      </span>
+    </button>
+  );
+}
\ No newline at end of file