diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..225d4a9
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1781577229,
+        "narHash": "sha256-lrp67w8AulE9Ks53n27I45ADSzbOCn4H+CNW1Ck8B+8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "567a49d1913ce81ac6e9582e3553dd90a955875f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..66d4e46
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,56 @@
+{
+  description = "qwen3-tts.cpp — dev environment (C++/GGML, CPU + Vulkan)";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+
+        # Vulkan toolchain needed to build ggml with -DGGML_VULKAN=ON:
+        # glslc/glslangValidator compile the .comp shaders, the loader +
+        # headers provide the API, spirv-tools links the shader pipeline.
+        vulkanInputs = [
+          pkgs.vulkan-headers
+          pkgs.vulkan-loader
+          pkgs.shaderc          # glslc
+          pkgs.glslang
+          pkgs.spirv-tools
+          pkgs.spirv-headers
+        ];
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = [
+            pkgs.cmake
+            pkgs.ninja
+            pkgs.pkg-config
+            pkgs.git
+            # Runtime/diagnostic helpers
+            pkgs.vulkan-tools     # vulkaninfo
+          ] ++ vulkanInputs;
+
+          # ggml's CMake finds Vulkan via the standard module; make sure the
+          # loader is also on the runtime path so the built CLI/libs resolve
+          # libvulkan when GGML_VULKAN is enabled.
+          LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath [ pkgs.vulkan-loader ];
+
+          shellHook = ''
+            echo "qwen3-tts.cpp dev shell"
+            echo "  cmake:  $(cmake --version | head -1)"
+            echo "  glslc:  $(glslc --version 2>/dev/null | head -1)"
+            echo
+            echo "Build ggml (CPU+Vulkan):"
+            echo "  cmake -S ggml -B ggml/build -G Ninja -DCMAKE_BUILD_TYPE=Release -DGGML_VULKAN=ON"
+            echo "  cmake --build ggml/build -j"
+            echo "Build qwen3-tts:"
+            echo "  cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release"
+            echo "  cmake --build build -j"
+          '';
+        };
+      });
+}
diff --git a/ggml b/ggml
index 5cecdad..3af5f57 160000
--- a/ggml
+++ b/ggml
@@ -1 +1 @@
-Subproject commit 5cecdad692d868e28dbd2f7c468504770108f30c
+Subproject commit 3af5f5760e19a96427f5f7a93b79cbdf3d4b265b