diff --git a/.github/workflows/build-deploy-tarball.yaml b/.github/workflows/build-deploy-tarball.yaml
new file mode 100644
index 0000000..a06f437
--- /dev/null
+++ b/.github/workflows/build-deploy-tarball.yaml
@@ -0,0 +1,133 @@
+name: Release Candidate
+
+on:
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  # -----------------------------------------------------------------------------
+  # JOB 1: Build Artifact
+  # -----------------------------------------------------------------------------
+  build:
+    if: github.head_ref == 'package-pre_prod'
+    runs-on: ubuntu-latest
+    outputs:
+      tarball: ${{ steps.pkg_info.outputs.tarball }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          r-version: 'release'
+
+      # Installs devtools AND system libraries (libcurl, etc.)
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: |
+            devtools
+            desc
+
+      - name: Build with devtools
+        id: pkg_info
+        run: |
+          # 1. Clean up old files (R syntax)
+          unlink(list.files(pattern = "\\.tar\\.gz$"))
+
+          # 2. Build
+          devtools::build(path = ".")
+
+          # 3. Capture filename (R syntax)
+          tarball_name <- list.files(pattern = "\\.tar\\.gz$")[1]
+
+          # 4. Save to GitHub Output (R syntax)
+          cat(paste0("tarball=", tarball_name, "\n"), file = Sys.getenv("GITHUB_OUTPUT"))
+        shell: Rscript {0}
+
+      - name: Save Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: cran-tarball
+          path: ${{ steps.pkg_info.outputs.tarball }}
+
+  # -----------------------------------------------------------------------------
+  # JOB 2: WinBuilder
+  # -----------------------------------------------------------------------------
+  winbuilder:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: r-lib/actions/setup-r@v2
+        with:
+           r-version: 'release'
+           use-public-rspm: true # Speeds up installation
+
+      # ADDED: Ensures devtools installs without missing system library errors
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: devtools
+
+      - name: Download Artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: cran-tarball
+          path: .
+
+      - name: Submit to WinBuilder
+        run: |
+          pkg_tarball <- "${{ needs.build.outputs.tarball }}"
+          print(paste("Submitting", pkg_tarball))
+
+          tryCatch(
+            devtools::check_win_release(pkg = pkg_tarball),
+            error = function(e) message("Release upload failed: ", e$message)
+          )
+
+          tryCatch(
+            devtools::check_win_devel(pkg = pkg_tarball),
+            error = function(e) message("Devel upload failed: ", e$message)
+          )
+        shell: Rscript {0}
+
+  # -----------------------------------------------------------------------------
+  # JOB 3: Validate
+  # -----------------------------------------------------------------------------
+  validate:
+    needs: build
+    runs-on: ${{ matrix.os }}
+    strategy:
+      #fail-fast: false
+      matrix:
+        os: [windows-latest, ubuntu-latest, macos-latest]
+
+    steps:
+      # Checkout is REQUIRED for setup-r-dependencies to read your DESCRIPTION file
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          r-version: 'release'
+          use-public-rspm: true
+
+      # ADDED: Installs dependencies safely on Linux (handles system libs like libxml2)
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          needs: check
+
+      - name: Download Artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: cran-tarball
+          path: .
+
+      - name: Install & Verify
+        run: |
+          pkg_tarball <- "${{ needs.build.outputs.tarball }}"
+
+          # Install the tarball
+          install.packages(pkg_tarball, repos = NULL, type = "source")
+
+          # Test load
+          library(gsub("_.*", "", pkg_tarball), character.only = TRUE)
+          print("SUCCESS: Package installed and loaded.")
+        shell: Rscript {0}
diff --git a/README.md b/README.md
index d628077..0a74721 100644
--- a/README.md
+++ b/README.md
@@ -113,14 +113,14 @@ fit_et <- nmar(
 summary(fit_et)
 #> NMAR Model Summary (Exponential tilting)
 #> =================================
-#> y mean: -1.003956
+#> y mean: -1.003974
 #> Converged: TRUE 
 #> Variance method: none 
 #> Call: nmar(y ~ x, data = <data.frame: N=?>, engine = exponential_tilting)
 #> 
 #> Response-model (theta) coefficients:
-#>   (Intercept)          : 0.864024
-#>   y                    : -0.170260
+#>   (Intercept)          : 0.864080
+#>   y                    : -0.170216
 ```
 
 Result objects returned by `nmar()` support methods such as `summary()`,