diff --git a/.agents/docs/2026-10-28-add-sdl3-mwrap-plan.md b/.agents/docs/2026-10-28-add-sdl3-mwrap-plan.md
new file mode 100644
index 00000000..04b1c759
--- /dev/null
+++ b/.agents/docs/2026-10-28-add-sdl3-mwrap-plan.md
@@ -0,0 +1,61 @@
+# Add mcpplibs.mwrap.sdl3 (sdl3-m 3.4.18)
+
+## Form
+
+- Third-party upstream [libsdl-org/SDL](https://github.com/libsdl-org/SDL), release `release-3.4.18`, zlib. The
+  tarball (`c4b08b95…92665c90`) is the one compat.sdl3 3.4.18 already pins.
+- Form A external mwrap module repository: [mcpplibs/sdl3-m](https://github.com/mcpplibs/sdl3-m), package
+  `mcpplibs.mwrap.sdl3`. The version is upstream's (first release of the identity, no revision suffix); tag
+  series `mwrap-${version}`.
+- Implementation ownership: the library is compat.sdl3's (its configuration and ABI are sufficient). The
+  wrapper vendors no upstream code; it retains SDL's README and license under `upstream/sdl3/` with checksums in
+  `upstream/documents.json`. No implementation is linked twice.
+
+## Modules
+
+- `mcpplibs.mwrap.sdl3`: every function, type, struct and enumerator of `<SDL3/SDL.h>` and its closure,
+  `SDL_vulkan.h`, `SDL_main.h`'s functions (included with `SDL_MAIN_HANDLED`: no `main` redefinition) and
+  `SDL_revision.h`, by `export using`, each under the `#if` its header declares it under (Linux 2773, macOS 2771,
+  Windows 2779 declarations). Generated from the pinned headers by `tools/gen_exports.py`.
+- The 16 `SDL_FORCE_INLINE` functions (`SDL_PointInRect`, `SDL_Swap32`, `SDL_size_mul_check_overflow` …) have
+  internal linkage; they are adapted under their names and signatures in `mcpplibs::mwrap::sdl3`, each calling
+  upstream's.
+- `mcpplibs.mwrap.sdl3.macros`: 1060 object-like macros as `inline constexpr` constants of the macro's own type
+  (strings as `const char[]`: `SDL_HINT_*`, `SDL_PROP_*`), 87 function-like macros as functions whose body is
+  the macro expanded in the module (`SDL_BUTTON_MASK`, `SDL_FOURCC`, `SDL_BITSPERPIXEL`, `SDL_CreateThread` …);
+  the bit-extracting ones are templates, as upstream applies them to integers and enums alike.
+- Stay macros, in `<mwrap/sdl3/macros.hpp>` (= `<SDL3/SDL.h>`): the assertions, `SDL_stack_alloc`,
+  stringification and pasting, attributes, the `SDL_PLATFORM_*` tests, SDL 2's names; every macro is listed with
+  its reason in `tools/policy.py`. Not wrapped (include directly): the Khronos GL/EGL headers SDL ships,
+  `SDL_intrin.h`, the SDL_test headers.
+
+## Verification
+
+Wrapper CI (Linux GCC 16.1 and LLVM 23.1.3, macOS LLVM, Windows LLVM, all required): build; tests through the
+module (init, properties, hints, events, timers, threads, IO, filesystem, pixels, surfaces, the software
+renderer and audio on the dummy drivers, a GPU device on lavapipe / Metal / Direct3D 12, required), the macro
+mappings, the header mixed with the import, `SDL_main.h` and the app callbacks; the export audit, which on each
+row preprocesses the headers with the module's own compile command and requires every declaration exported,
+every inline function adapted and every macro mapped or listed; and SDL's own `testautomation` (26 suites, 377
+tests) compiled as C++ against the module (its SDL includes replaced by the import and the side macros) and run
+as upstream's CTest runs it, with and without SIMD: 0 failures on every row. The templates job scaffolds the
+default `info` template (headless) as an installed package and runs it, and builds the `window` template.
+
+Here, with the CI-pinned mcpp 2026.10.26.1:
+
+- `bash tests/run_members.sh sdl3-headless`: the real release archive through the candidate index; events,
+  properties, the software renderer read back, an audio conversion, the mapped macros: `test result ok`.
+- `python3 tests/mwrap/check_installed_template.py --package mcpplibs.mwrap.sdl3@3.4.18`: the installed archive
+  and the unmodified default template.
+
+## Mirror and updates
+
+No `mcpp-res` access in this change, so the descriptor uses the GitHub release URL as a plain string (CN users
+fall back to it); a maintainer can add the GitCode mirror with identical bytes. `extensions.autoupdate` follows
+the repository's own `mwrap-${version}` tags.
+
+## Motivation
+
+openmui's desktop host (openmui.host.sdl3) and SDL_GPU backend (openmui.rhi.sdl) use SDL3. Through this module
+their native units import SDL (`import mcpplibs.mwrap.sdl3;` and
+`using namespace mcpplibs::mwrap::sdl3::macros;`) instead of including its headers.
diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index b098ad7a..6021ffe8 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -1643,6 +1643,11 @@ jobs:
         shell: bash
         run: python3 tests/mwrap/check_installed_template.py --mcpp "$MCPP" --package mcpplibs.mwrap.harfbuzz@14.3.0 --deploy
 
+      - name: Installed SDL3 wrapper archive, actual default info template and its relocated notices
+        if: contains(format(' {0} ', env.MEMBERS), ' sdl3-headless ') && matrix.toolchain == 'default'
+        shell: bash
+        run: python3 tests/mwrap/check_installed_template.py --mcpp "$MCPP" --package mcpplibs.mwrap.sdl3@3.4.18 --deploy
+
       - name: Installed Godot wrapper archive and actual standalone math template
         if: contains(format(' {0} ', env.MEMBERS), ' godot-math ') && matrix.toolchain == 'default'
         shell: bash
diff --git a/mcpp.toml b/mcpp.toml
index ae69346c..17c065c2 100644
--- a/mcpp.toml
+++ b/mcpp.toml
@@ -24,6 +24,7 @@ members = [
     "tests/mwrap/fribidi-bidi",
     "tests/mwrap/freetype-render",
     "tests/mwrap/harfbuzz-shape",
+    "tests/mwrap/sdl3-headless",
     "tests/mwrap/grpc-cpu",
     "tests/mwrap/grpc-tools",
     "tests/mwrap/godot-math",
diff --git a/pkgs/mwrap/sdl3.lua b/pkgs/mwrap/sdl3.lua
new file mode 100644
index 00000000..bc129091
--- /dev/null
+++ b/pkgs/mwrap/sdl3.lua
@@ -0,0 +1,38 @@
+-- Immutable upstream-aligned mwrap source release (sdl3-m mwrap-3.4.18).
+-- The CN mirror is added by a maintainer with mcpp-res access; until then CN
+-- users fall back to the GitHub release (docs/cn-mirror.md).
+package = {
+    spec = "1",
+    namespace = "mcpplibs.mwrap",
+    name = "sdl3",
+    description = "sdl3-m: SDL 3 (window, input, audio, GPU and platform layer) as C++23 modules",
+    licenses = { "Apache-2.0" },
+    repo = "https://github.com/mcpplibs/sdl3-m",
+    type = "package",
+    extensions = {
+        autoupdate = {
+            tag = "mwrap-${version}",
+            url = "https://github.com/mcpplibs/sdl3-m/releases/download/${tag}/sdl3-m-${version}.tar.gz",
+        },
+    },
+    xpm = {
+        linux = {
+            ["3.4.18"] = {
+                url = "https://github.com/mcpplibs/sdl3-m/releases/download/mwrap-3.4.18/sdl3-m-3.4.18.tar.gz",
+                sha256 = "e056750efe3bdb9e03457cb202d7a17f9c942630637656f382ac0604d8a66d08",
+            },
+        },
+        macosx = {
+            ["3.4.18"] = {
+                url = "https://github.com/mcpplibs/sdl3-m/releases/download/mwrap-3.4.18/sdl3-m-3.4.18.tar.gz",
+                sha256 = "e056750efe3bdb9e03457cb202d7a17f9c942630637656f382ac0604d8a66d08",
+            },
+        },
+        windows = {
+            ["3.4.18"] = {
+                url = "https://github.com/mcpplibs/sdl3-m/releases/download/mwrap-3.4.18/sdl3-m-3.4.18.tar.gz",
+                sha256 = "e056750efe3bdb9e03457cb202d7a17f9c942630637656f382ac0604d8a66d08",
+            },
+        },
+    },
+}
diff --git a/tests/mwrap/check_installed_template.py b/tests/mwrap/check_installed_template.py
index 3d086827..7488b5c2 100644
--- a/tests/mwrap/check_installed_template.py
+++ b/tests/mwrap/check_installed_template.py
@@ -204,6 +204,24 @@ def main():
                 assert b"Apache License" in (roots[0] / "LICENSE").read_bytes()
                 assert b"mcpp-community" in (roots[0] / "NOTICE").read_bytes()
                 print(f"Verified {len(declared)} byte-identical wrapper/HarfBuzz license files", flush=True)
+            elif identity == "mcpplibs.mwrap.sdl3":
+                # SDL is zlib-licensed and linked statically: its license and
+                # README travel with the program, beside the wrapper's.
+                sources = [path for store in (home / "xpkgs", home / "registry/data/xpkgs")
+                           for path in store.glob(f"mcpplibs.mwrap-x-sdl3/{version}/*/src/sdl3.cppm")]
+                assert len(sources) == 1, sources
+                source = sources[0].parent.parent
+                declared = tomllib.loads((source / "mcpp.toml").read_text(encoding="utf-8"))["runtime"]["deploy"]
+                roots = list(relocated.rglob("licenses/sdl3"))
+                assert len(roots) == 1, f"Missing SDL runtime license tree: {roots}"
+                for entry in declared:
+                    notice = source / entry["from"]
+                    copied = roots[0].parent.parent / entry["to"] / notice.name
+                    assert copied.is_file() and copied.read_bytes() == notice.read_bytes(), copied
+                assert b"Sam Lantinga" in (roots[0] / "upstream/sdl3/LICENSE.txt").read_bytes()
+                assert b"Apache License" in (roots[0] / "LICENSE").read_bytes()
+                assert b"mcpp-community" in (roots[0] / "NOTICE").read_bytes()
+                print(f"Verified {len(declared)} byte-identical wrapper/SDL license files", flush=True)
             else:
                 raise ValueError(f"No deployment acceptance contract for {identity}")
             runtime_env = {key: value for key, value in os.environ.items()
diff --git a/tests/mwrap/sdl3-headless/mcpp.toml b/tests/mwrap/sdl3-headless/mcpp.toml
new file mode 100644
index 00000000..86ecbb3e
--- /dev/null
+++ b/tests/mwrap/sdl3-headless/mcpp.toml
@@ -0,0 +1,11 @@
+[package]
+name = "sdl3-headless"
+version = "3.4.18"
+description = "Consume the immutable SDL3 wrapper headless: events, properties, a surface, the software renderer on the dummy driver, an audio stream, the mapped macros"
+
+[indices]
+# Use the complete candidate built-in index prepared by tests/run_members.sh.
+# An explicit empty table overrides the legacy workspace redirect.
+
+[dependencies]
+"mcpplibs.mwrap.sdl3" = "3.4.18"
diff --git a/tests/mwrap/sdl3-headless/tests/behavior.cpp b/tests/mwrap/sdl3-headless/tests/behavior.cpp
new file mode 100644
index 00000000..8798eb6d
--- /dev/null
+++ b/tests/mwrap/sdl3-headless/tests/behavior.cpp
@@ -0,0 +1,60 @@
+import std;
+import mcpplibs.mwrap.sdl3;
+
+using namespace mcpplibs::mwrap::sdl3;          // the adapted inline API
+using namespace mcpplibs::mwrap::sdl3::macros;  // SDL_INIT_VIDEO, SDL_HINT_*, SDL_BITSPERPIXEL ...
+
+int main() {
+    // SDL's headless drivers, over whatever the environment says.
+    SDL_SetHintWithPriority(SDL_HINT_VIDEO_DRIVER, "dummy", SDL_HINT_OVERRIDE);
+    SDL_SetHintWithPriority(SDL_HINT_AUDIO_DRIVER, "dummy", SDL_HINT_OVERRIDE);
+    if (SDL_GetVersion() != SDL_VERSION || !SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO)) return 1;
+
+    // Properties and a user event, pushed and polled.
+    const SDL_PropertiesID props = SDL_CreateProperties();
+    SDL_SetStringProperty(props, "name", "sdl3-headless");
+    if (std::string_view(SDL_GetStringProperty(props, "name", "")) != "sdl3-headless") return 2;
+    SDL_DestroyProperties(props);
+    const Uint32 type = SDL_RegisterEvents(1);
+    SDL_Event e{};
+    e.type = type;
+    e.user.code = 42;
+    if (!SDL_PushEvent(&e)) return 3;
+    int code = 0;
+    while (SDL_PollEvent(&e))
+        if (e.type == type) code = e.user.code;
+    if (code != 42) return 4;
+
+    // A window and the software renderer: a filled square read back.
+    SDL_Window* window = nullptr;
+    SDL_Renderer* renderer = nullptr;
+    if (!SDL_CreateWindowAndRenderer("sdl3-headless", 32, 32, SDL_WINDOW_HIDDEN, &window, &renderer)) return 5;
+    SDL_SetRenderDrawColor(renderer, 0, 0, 0, SDL_ALPHA_OPAQUE);
+    SDL_RenderClear(renderer);
+    SDL_SetRenderDrawColor(renderer, 255, 128, 0, SDL_ALPHA_OPAQUE);
+    const SDL_FRect square{8, 8, 16, 16};
+    SDL_RenderFillRect(renderer, &square);
+    SDL_Surface* frame = SDL_RenderReadPixels(renderer, nullptr);
+    Uint8 r = 0, g = 0, b = 0, a = 0;
+    if (!frame || !SDL_ReadSurfacePixel(frame, 16, 16, &r, &g, &b, &a) || r != 255 || g != 128 || b != 0) return 6;
+    SDL_DestroySurface(frame);
+    SDL_DestroyRenderer(renderer);
+    SDL_DestroyWindow(window);
+
+    // Pixel-format macros, an inline rectangle function, an audio conversion.
+    static_assert(SDL_BITSPERPIXEL(SDL_PIXELFORMAT_ARGB8888) == 32 && SDL_FOURCC('Y', 'V', '1', '2') == SDL_PIXELFORMAT_YV12);
+    const SDL_Rect rect{0, 0, 4, 4};
+    const SDL_Point inside{1, 2};
+    if (!SDL_PointInRect(&inside, &rect)) return 7;
+    const SDL_AudioSpec from{SDL_AUDIO_S16, 1, 8000}, to{SDL_AUDIO_F32, 1, 8000};
+    SDL_AudioStream* stream = SDL_CreateAudioStream(&from, &to);
+    const Sint16 half = 16384;
+    float out = 0;
+    if (!stream || !SDL_PutAudioStreamData(stream, &half, sizeof half) || !SDL_FlushAudioStream(stream) ||
+        SDL_GetAudioStreamData(stream, &out, sizeof out) != sizeof out || out != 0.5f)
+        return 8;
+    SDL_DestroyAudioStream(stream);
+    SDL_Quit();
+    std::println("sdl3-headless: ok (SDL {}.{}.{}, {})", SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_MICRO_VERSION, SDL_GetPlatform());
+    return 0;
+}