diff --git a/.github/workflows/flutter-ci.yml b/.github/workflows/flutter-ci.yml
index 984e4b4..e7f9d67 100644
--- a/.github/workflows/flutter-ci.yml
+++ b/.github/workflows/flutter-ci.yml
@@ -1,24 +1,73 @@
-name: Flutter CI
+name: Build and Release Artifacts
 
 on:
   pull_request:
     paths:
       - ".github/workflows/flutter-ci.yml"
+      - "README.md"
       - "flutter_app/**"
   push:
     branches:
       - main
     tags:
       - "v*"
+    paths:
+      - ".github/workflows/flutter-ci.yml"
+      - "README.md"
+      - "flutter_app/**"
   workflow_dispatch:
+    inputs:
+      release_tag:
+        description: "Optional tag to create/update a GitHub Release for this build, for example v1.0.0."
+        required: false
+        type: string
+      prerelease:
+        description: "Mark a manually created GitHub Release as a pre-release."
+        required: false
+        default: true
+        type: boolean
 
 permissions:
   contents: write
 
+env:
+  FLUTTER_CHANNEL: stable
+  FLUTTER_APP_DIR: flutter_app
+
 jobs:
-  flutter:
-    name: Test and build Flutter app
+  validate:
+    name: Validate Flutter app
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: flutter_app
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v6
+
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ env.FLUTTER_CHANNEL }}
+          cache: true
+
+      - name: Resolve Flutter dependencies
+        run: flutter pub get
+
+      - name: Check formatting
+        run: dart format --output=none --set-exit-if-changed lib test
+
+      - name: Analyze Flutter app
+        run: flutter analyze
+
+      - name: Run Flutter tests
+        run: flutter test
+
+  build-android:
+    name: Build Android APK
     runs-on: ubuntu-latest
+    needs: validate
     defaults:
       run:
         working-directory: flutter_app
@@ -36,14 +85,11 @@ jobs:
           distribution: temurin
           java-version: "21"
 
-      - name: Install Flutter stable
-        run: |
-          FLUTTER_ROOT="$RUNNER_TOOL_CACHE/flutter-stable"
-          rm -rf "$FLUTTER_ROOT"
-          git clone --depth 1 --branch stable https://github.com/flutter/flutter.git "$FLUTTER_ROOT"
-          echo "FLUTTER_ROOT=$FLUTTER_ROOT" >> "$GITHUB_ENV"
-          echo "$FLUTTER_ROOT/bin" >> "$GITHUB_PATH"
-          "$FLUTTER_ROOT/bin/flutter" --version
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ env.FLUTTER_CHANNEL }}
+          cache: true
 
       - name: Install Android SDK packages
         run: |
@@ -55,43 +101,272 @@ jobs:
       - name: Resolve Flutter dependencies
         run: flutter pub get
 
-      - name: Check formatting
-        run: dart format --output=none --set-exit-if-changed lib test
-
-      - name: Analyze Flutter app
-        run: flutter analyze
-
-      - name: Run Flutter tests
-        run: flutter test
-
-      - name: Build Android debug APK
-        run: flutter build apk --debug
-
       - name: Build Android release APK
         run: flutter build apk --release
 
-      - name: Stage Android release APK
+      - name: Stage Android artifact
         run: |
+          set -euo pipefail
+          version="$(awk '/^version:/ { print $2 }' pubspec.yaml | tr '+' '-')"
           mkdir -p "$RUNNER_TEMP/studyos-agent"
           cp build/app/outputs/flutter-apk/app-release.apk \
-            "$RUNNER_TEMP/studyos-agent/studyos-agent-android-release.apk"
+            "$RUNNER_TEMP/studyos-agent/studyos-agent-${version}-android.apk"
+          (cd "$RUNNER_TEMP/studyos-agent" && sha256sum "studyos-agent-${version}-android.apk" > "studyos-agent-${version}-android.apk.sha256")
+
+      - name: Upload Android APK
+        uses: actions/upload-artifact@v7
+        with:
+          name: studyos-agent-android-apk
+          path: ${{ runner.temp }}/studyos-agent/*
+          if-no-files-found: error
+
+  build-web:
+    name: Build Web bundle
+    runs-on: ubuntu-latest
+    needs: validate
+    defaults:
+      run:
+        working-directory: flutter_app
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v6
+
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ env.FLUTTER_CHANNEL }}
+          cache: true
+
+      - name: Resolve Flutter dependencies
+        run: flutter pub get
+
+      - name: Build web app
+        run: flutter build web --release
+
+      - name: Stage web artifact
+        run: |
+          set -euo pipefail
+          version="$(awk '/^version:/ { print $2 }' pubspec.yaml | tr '+' '-')"
+          artifact="$RUNNER_TEMP/studyos-agent-web-${version}.zip"
+          (cd build/web && zip -r "$artifact" .)
+          sha256sum "$artifact" > "$artifact.sha256"
+
+      - name: Upload web bundle
+        uses: actions/upload-artifact@v7
+        with:
+          name: studyos-agent-web
+          path: |
+            ${{ runner.temp }}/studyos-agent-web-*.zip
+            ${{ runner.temp }}/studyos-agent-web-*.zip.sha256
+          if-no-files-found: error
+
+  build-linux:
+    name: Build Linux x64 bundle
+    runs-on: ubuntu-latest
+    needs: validate
+    defaults:
+      run:
+        working-directory: flutter_app
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v6
+
+      - name: Install Linux build dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y clang cmake ninja-build pkg-config libgtk-3-dev liblzma-dev
+
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ env.FLUTTER_CHANNEL }}
+          cache: true
+
+      - name: Enable Linux desktop
+        run: flutter config --enable-linux-desktop
+
+      - name: Resolve Flutter dependencies
+        run: flutter pub get
+
+      - name: Build Linux app
+        run: flutter build linux --release
+
+      - name: Stage Linux artifact
+        run: |
+          set -euo pipefail
+          version="$(awk '/^version:/ { print $2 }' pubspec.yaml | tr '+' '-')"
+          artifact="$RUNNER_TEMP/studyos-agent-${version}-linux-x64.tar.gz"
+          tar -C build/linux/x64/release -czf "$artifact" bundle
+          sha256sum "$artifact" > "$artifact.sha256"
+
+      - name: Upload Linux bundle
+        uses: actions/upload-artifact@v7
+        with:
+          name: studyos-agent-linux-x64
+          path: |
+            ${{ runner.temp }}/studyos-agent-*-linux-x64.tar.gz
+            ${{ runner.temp }}/studyos-agent-*-linux-x64.tar.gz.sha256
+          if-no-files-found: error
+
+  build-macos:
+    name: Build macOS app
+    runs-on: macos-latest
+    needs: validate
+    defaults:
+      run:
+        working-directory: flutter_app
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v6
+
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ env.FLUTTER_CHANNEL }}
+          cache: true
 
-      - name: Upload Android APK artifact
+      - name: Enable macOS desktop
+        run: flutter config --enable-macos-desktop
+
+      - name: Resolve Flutter dependencies
+        run: flutter pub get
+
+      - name: Build macOS app
+        run: flutter build macos --release
+
+      - name: Stage macOS artifact
+        run: |
+          set -euo pipefail
+          version="$(awk '/^version:/ { print $2 }' pubspec.yaml | tr '+' '-')"
+          artifact="$RUNNER_TEMP/studyos-agent-${version}-macos.zip"
+          ditto -c -k --sequesterRsrc --keepParent \
+            build/macos/Build/Products/Release/studyos_agent.app \
+            "$artifact"
+          shasum -a 256 "$artifact" > "$artifact.sha256"
+
+      - name: Upload macOS app
         uses: actions/upload-artifact@v7
         with:
-          name: studyos-agent-android-release-apk
-          path: ${{ runner.temp }}/studyos-agent/studyos-agent-android-release.apk
+          name: studyos-agent-macos
+          path: |
+            ${{ runner.temp }}/studyos-agent-*-macos.zip
+            ${{ runner.temp }}/studyos-agent-*-macos.zip.sha256
           if-no-files-found: error
 
-      - name: Attach APK to GitHub Release
-        if: startsWith(github.ref, 'refs/tags/v')
+  build-windows:
+    name: Build Windows x64 app
+    runs-on: windows-latest
+    needs: validate
+    defaults:
+      run:
+        working-directory: flutter_app
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v6
+
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ env.FLUTTER_CHANNEL }}
+          cache: true
+
+      - name: Enable Windows desktop
+        run: flutter config --enable-windows-desktop
+
+      - name: Resolve Flutter dependencies
+        run: flutter pub get
+
+      - name: Build Windows app
+        run: flutter build windows --release
+
+      - name: Stage Windows artifact
+        shell: pwsh
+        run: |
+          $version = (Select-String -Path pubspec.yaml -Pattern '^version:\s*(\S+)' | ForEach-Object { $_.Matches[0].Groups[1].Value }).Replace('+', '-')
+          $artifact = "$env:RUNNER_TEMP\studyos-agent-$version-windows-x64.zip"
+          Compress-Archive -Path build\windows\x64\runner\Release\* -DestinationPath $artifact -Force
+          Get-FileHash -Algorithm SHA256 $artifact | ForEach-Object { "$($_.Hash.ToLower())  $(Split-Path $artifact -Leaf)" } | Set-Content "$artifact.sha256"
+
+      - name: Upload Windows app
+        uses: actions/upload-artifact@v7
+        with:
+          name: studyos-agent-windows-x64
+          path: |
+            ${{ runner.temp }}/studyos-agent-*-windows-x64.zip
+            ${{ runner.temp }}/studyos-agent-*-windows-x64.zip.sha256
+          if-no-files-found: error
+
+  release:
+    name: Publish GitHub Release
+    runs-on: ubuntu-latest
+    needs:
+      - build-android
+      - build-web
+      - build-linux
+      - build-macos
+      - build-windows
+    if: github.event_name != 'pull_request'
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 2
+
+      - name: Decide whether to publish
+        id: release
+        env:
+          INPUT_RELEASE_TAG: ${{ inputs.release_tag }}
+        run: |
+          set -euo pipefail
+
+          if [[ "$GITHUB_REF" == refs/tags/v* ]]; then
+            release_tag="$GITHUB_REF_NAME"
+          elif [[ "$GITHUB_EVENT_NAME" == "workflow_dispatch" && -n "${INPUT_RELEASE_TAG:-}" ]]; then
+            release_tag="$INPUT_RELEASE_TAG"
+          elif [[ "$GITHUB_EVENT_NAME" == "push" && "$GITHUB_REF" == "refs/heads/main" ]]; then
+            current_version="$(awk '/^version:/ { print $2 }' flutter_app/pubspec.yaml)"
+            previous_version="$(git show HEAD^:flutter_app/pubspec.yaml 2>/dev/null | awk '/^version:/ { print $2 }' || true)"
+            if [[ -z "$current_version" || "$current_version" == "$previous_version" ]]; then
+              echo "should_publish=false" >> "$GITHUB_OUTPUT"
+              exit 0
+            fi
+            release_tag="v$current_version"
+          else
+            echo "should_publish=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          echo "should_publish=true" >> "$GITHUB_OUTPUT"
+          echo "release_tag=$release_tag" >> "$GITHUB_OUTPUT"
+
+      - name: Download build artifacts
+        if: steps.release.outputs.should_publish == 'true'
+        uses: actions/download-artifact@v7
+        with:
+          path: ${{ runner.temp }}/studyos-release
+          merge-multiple: true
+
+      - name: Publish release artifacts
+        if: steps.release.outputs.should_publish == 'true'
         env:
           GH_TOKEN: ${{ github.token }}
+          RELEASE_TAG: ${{ steps.release.outputs.release_tag }}
+          INPUT_PRERELEASE: ${{ inputs.prerelease }}
         run: |
-          gh release view "$GITHUB_REF_NAME" >/dev/null 2>&1 || \
-            gh release create "$GITHUB_REF_NAME" \
-              --title "$GITHUB_REF_NAME" \
-              --notes "StudyOS Agent Android release for $GITHUB_REF_NAME."
-          gh release upload "$GITHUB_REF_NAME" \
-            "$RUNNER_TEMP/studyos-agent/studyos-agent-android-release.apk" \
+          set -euo pipefail
+
+          release_args=(--title "$RELEASE_TAG" --notes "StudyOS Agent builds for $RELEASE_TAG." --target "$GITHUB_SHA")
+          if [[ "$GITHUB_EVENT_NAME" == "workflow_dispatch" && "${INPUT_PRERELEASE:-false}" == "true" ]]; then
+            release_args+=(--prerelease)
+          fi
+
+          gh release view "$RELEASE_TAG" >/dev/null 2>&1 || \
+            gh release create "$RELEASE_TAG" "${release_args[@]}"
+          gh release upload "$RELEASE_TAG" \
+            "$RUNNER_TEMP"/studyos-release/* \
             --clobber
diff --git a/README.md b/README.md
index 1c6b1c0..8e4fece 100644
--- a/README.md
+++ b/README.md
@@ -33,3 +33,23 @@ flutter run
 The first migration PR is intentionally a bridge-first implementation. It
 does not rewrite every Android service in Dart because many current features
 are Android-specific and should stay behind native adapters.
+
+## Installing builds
+
+Installable app bundles are built by the `Build and Release Artifacts` GitHub
+Actions workflow for Android, web, Linux, macOS, and Windows. iOS is skipped
+because distribution needs to go through Apple's signing and App Store/TestFlight
+flow.
+
+- For branch and pull request builds, open the workflow run and download the
+  platform artifact you need, such as `studyos-agent-android-apk`,
+  `studyos-agent-web`, `studyos-agent-linux-x64`, `studyos-agent-macos`, or
+  `studyos-agent-windows-x64`.
+- For tagged releases such as `v1.0.0`, or a `flutter_app/pubspec.yaml`
+  version change on `main`, download the platform artifact from the matching
+  GitHub Release.
+
+Android may ask you to allow installing APKs from your browser or file manager
+before opening the downloaded build. The APK is currently signed with the
+debug signing configuration from the Flutter Android runner, so it is suitable
+for course testing but not yet for app-store distribution.