diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0e38a2a..bb84e56 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -4,157 +4,27 @@ on:
   push:
     branches: [main]
   pull_request:
-    branches: [main]
-
-env:
-  XLINGS_VERSION: v0.4.0
 
 jobs:
-  build-linux:
-    runs-on: ubuntu-24.04
+  build:
+    name: build (linux x86_64, mcpp)
+    runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Install system deps
-        run: |
-          sudo apt-get update -qq
-          sudo apt-get install -y curl git build-essential
+      - uses: actions/checkout@v4
 
-      - name: Install Xlings
+      - name: Install xlings
         env:
-          XLINGS_NON_INTERACTIVE: 1
-        run: |
-          VERSION_NUM="${XLINGS_VERSION#v}"
-          TARBALL="xlings-${VERSION_NUM}-linux-x86_64.tar.gz"
-          curl -fSL -o "$RUNNER_TEMP/$TARBALL" "https://github.com/d2learn/xlings/releases/download/${XLINGS_VERSION}/${TARBALL}"
-          tar -xzf "$RUNNER_TEMP/$TARBALL" -C "$RUNNER_TEMP"
-          EXTRACT_DIR=$(find "$RUNNER_TEMP" -maxdepth 1 -type d -name "xlings-*" | head -1)
-          chmod +x "$EXTRACT_DIR/bin/xlings"
-          "$EXTRACT_DIR/bin/xlings" self install
-          echo "PATH=$HOME/.xlings/subos/current/bin:$PATH" >> "$GITHUB_ENV"
-
-      - name: Install project dependencies via Xlings
-        run: |
-          xlings install
-          xmake --version
-          gcc --version
-
-      - name: Build with xmake
-        run: |
-          xmake f -m release -y -vvD
-          xmake -a -j"$(nproc)"
-
-      - name: Run tests
+          XLINGS_VERSION: 0.4.25
         run: |
-          xmake run test_socket -y
-          xmake run test_tls -y
-          xmake run test_http -y
-          xmake run test_sse -y
-          xmake run test_http_stream -y
-          xmake run test_proxy -y
-          xmake run test_integration -y
-          xmake run test_types -y
-          xmake run test_serialization -y
-          xmake run test_coro -y
-          xmake run test_client -y
-          xmake run test_openai_serialize -y
-          xmake run test_anthropic_serialize -y
-          xmake run test_tool_calling -y
-          xmake run test_structured_output -y
-          xmake run test_embeddings -y
-          xmake run test_llmapi_integration -y
+          tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
+          curl -fsSL -o "/tmp/${tarball}" \
+            "https://github.com/d2learn/xlings/releases/download/v${XLINGS_VERSION}/${tarball}"
+          tar -xzf "/tmp/${tarball}" -C /tmp
+          "/tmp/xlings-${XLINGS_VERSION}-linux-x86_64/subos/default/bin/xlings" self install
+          echo "$HOME/.xlings/subos/current/bin" >> "$GITHUB_PATH"
 
-  build-macos:
-    runs-on: macos-15
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Install Xlings
-        env:
-          XLINGS_NON_INTERACTIVE: 1
-        run: |
-          VERSION_NUM="${XLINGS_VERSION#v}"
-          TARBALL="xlings-${VERSION_NUM}-macosx-arm64.tar.gz"
-          curl -fSL -o "$RUNNER_TEMP/$TARBALL" "https://github.com/d2learn/xlings/releases/download/${XLINGS_VERSION}/${TARBALL}"
-          tar -xzf "$RUNNER_TEMP/$TARBALL" -C "$RUNNER_TEMP"
-          EXTRACT_DIR=$(find "$RUNNER_TEMP" -maxdepth 1 -type d -name "xlings-*" | head -1)
-          xattr -dr com.apple.quarantine "$EXTRACT_DIR" 2>/dev/null || true
-          chmod +x "$EXTRACT_DIR/bin/xlings"
-          "$EXTRACT_DIR/bin/xlings" self install
-          echo "PATH=$HOME/.xlings/subos/current/bin:$PATH" >> "$GITHUB_ENV"
+      - name: Install workspace tools (.xlings.json → mcpp 0.0.3)
+        run: xlings install -y
 
-      - name: Install project dependencies via Xlings
-        run: |
-          xlings install
-          clang --version
-
-      - name: Configure xmake
-        run: |
-          LLVM_ROOT="$HOME/.xlings/data/xpkgs/xim-x-llvm"
-          LLVM_SDK=$(find "$LLVM_ROOT" -mindepth 1 -maxdepth 1 -type d | sort -V | tail -1)
-          test -d "$LLVM_SDK"
-          "$LLVM_SDK/bin/clang++" --version
-          xmake f -m release --toolchain=llvm --sdk="$LLVM_SDK" -y -vvD
-
-      - name: Build with xmake
-        run: xmake -a -j"$(sysctl -n hw.logicalcpu)"
-
-      - name: Run tests
-        run: |
-          xmake run test_socket -y
-          xmake run test_tls -y
-          xmake run test_http -y
-          xmake run test_sse -y
-          xmake run test_http_stream -y
-          xmake run test_proxy -y
-          xmake run test_integration -y
-          xmake run test_types -y
-          xmake run test_serialization -y
-          xmake run test_coro -y
-          xmake run test_client -y
-          xmake run test_openai_serialize -y
-          xmake run test_anthropic_serialize -y
-          xmake run test_tool_calling -y
-          xmake run test_structured_output -y
-          xmake run test_embeddings -y
-          xmake run test_llmapi_integration -y
-
-  build-windows:
-    runs-on: windows-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Setup xmake
-        uses: xmake-io/github-action-setup-xmake@v1
-        with:
-          xmake-version: latest
-
-      - name: Build with xmake
-        shell: pwsh
-        run: |
-          xmake f -m release -y -vvD
-          xmake -a -j$env:NUMBER_OF_PROCESSORS
-
-      - name: Run tests
-        shell: pwsh
-        run: |
-          xmake run test_socket -y
-          xmake run test_tls -y
-          xmake run test_http -y
-          xmake run test_sse -y
-          xmake run test_http_stream -y
-          xmake run test_proxy -y
-          xmake run test_integration -y
-          xmake run test_types -y
-          xmake run test_serialization -y
-          xmake run test_coro -y
-          xmake run test_client -y
-          xmake run test_openai_serialize -y
-          xmake run test_anthropic_serialize -y
-          xmake run test_tool_calling -y
-          xmake run test_structured_output -y
-          xmake run test_embeddings -y
-          xmake run test_llmapi_integration -y
+      - name: Build with mcpp
+        run: mcpp build
diff --git a/.xlings.json b/.xlings.json
index 380bca6..f2be3fd 100644
--- a/.xlings.json
+++ b/.xlings.json
@@ -1,9 +1,5 @@
 {
   "workspace": {
-    "cmake": "4.0.2",
-    "ninja": "1.12.1",
-    "xmake": "3.0.7",
-    "gcc": { "linux": "15.1.0" },
-    "llvm": { "macosx": "20.1.7" }
+    "mcpp": { "linux": "0.0.3" }
   }
-}
\ No newline at end of file
+}