diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6deacc9..4475741 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,6 +51,30 @@ jobs:
       - name: Run Rust tests
         run: cargo test --workspace
 
+  cross-platform:
+    name: cross-platform (${{ matrix.os }})
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Cache Rust build
+        uses: Swatinem/rust-cache@v2
+
+      # The library crates carry the platform-sensitive logic (agent detection,
+      # git, persistence). Testing them on Windows and macOS guards against
+      # cross-platform regressions without the heavy WebView GUI build.
+      - name: Run library crate tests
+        run: cargo test -p opencherry_core -p opencherry_repo -p opencherry_agents -p opencherry_persistence
+
   desktop-frontend:
     runs-on: ubuntu-latest
 
diff --git a/.github/workflows/release-macos.yml b/.github/workflows/release-macos.yml
new file mode 100644
index 0000000..62d0de2
--- /dev/null
+++ b/.github/workflows/release-macos.yml
@@ -0,0 +1,82 @@
+name: Release (macOS)
+
+# Builds the OpenCherry desktop app as a macOS disk image (.dmg), for both
+# Apple Silicon (aarch64) and Intel (x86_64).
+#
+# Triggers:
+#   - Push of a tag matching `v*` (e.g. v0.0.1) — attaches the .dmg files to the
+#     matching GitHub Release.
+#   - Manual `workflow_dispatch` — uploads the .dmg files as build artifacts
+#     only (no release), useful for contributors without a Mac.
+#
+# The images are unsigned and not notarized: on first launch macOS Gatekeeper
+# may block the app (right-click → Open to bypass).
+
+on:
+  push:
+    tags:
+      - "v*"
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  build-macos:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - target: aarch64-apple-darwin
+            arch: aarch64
+          - target: x86_64-apple-darwin
+            arch: x86_64
+    runs-on: macos-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+
+      - name: Cache Rust build
+        uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: ". -> target"
+          key: ${{ matrix.target }}
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: pnpm
+          cache-dependency-path: apps/desktop/pnpm-lock.yaml
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+        working-directory: apps/desktop
+
+      - name: Build .dmg
+        run: pnpm tauri build --bundles dmg --target ${{ matrix.target }}
+        working-directory: apps/desktop
+
+      - name: Upload .dmg artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: opencherry-macos-${{ matrix.arch }}-dmg
+          path: target/${{ matrix.target }}/release/bundle/dmg/*.dmg
+          if-no-files-found: error
+
+      - name: Attach .dmg to release
+        if: startsWith(github.ref, 'refs/tags/v')
+        uses: softprops/action-gh-release@v2
+        with:
+          files: target/${{ matrix.target }}/release/bundle/dmg/*.dmg
diff --git a/AGENTS.md b/AGENTS.md
index 29efedb..39f907d 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -49,7 +49,9 @@ E2E (separate package — do not run via root pnpm):
 
 ## CI expectations (`.github/workflows/ci.yml`)
 
-Three jobs run on Ubuntu: `cargo test --workspace`, frontend `pnpm test` + `pnpm build`, and the desktop E2E (installs `tauri-driver` + `webkitgtk-webdriver`). Match these locally before pushing.
+Four jobs: three on Ubuntu — `cargo test --workspace`, frontend `pnpm test` + `pnpm build`, and the desktop E2E (installs `tauri-driver` + `webkitgtk-webdriver`) — plus a `cross-platform` matrix that runs the library crate tests (`opencherry_core`/`repo`/`agents`/`persistence`) on `windows-latest` and `macos-latest`. Match these locally before pushing. Platform-specific logic (agent detection `.exe`/shell handling, path separators) must stay portable so the cross-platform job stays green.
+
+Release bundles are built by `release-linux.yml` (`.deb`), `release-windows.yml` (NSIS `.exe`), and `release-macos.yml` (`.dmg`, aarch64 + x86_64), triggered by `v*` tags or `workflow_dispatch`.
 
 ## Validation checklist after changes
 
diff --git a/README.md b/README.md
index b947cce..457fb66 100644
--- a/README.md
+++ b/README.md
@@ -132,9 +132,24 @@ sudo apt install libwebkit2gtk-4.1-dev \
   libayatana-appindicator3-dev
 ```
 
-#### Toolchain
+#### System dependencies (macOS)
 
-- Rust stable (1.80+)
+- Xcode Command Line Tools: `xcode-select --install`
+
+WebKit (the WebView used by Tauri) ships with macOS, so there is nothing else
+to install for the GUI.
+
+#### System dependencies (Windows)
+
+- Microsoft Visual Studio C++ Build Tools (MSVC linker)
+- WebView2 runtime (preinstalled on Windows 10/11)
+
+`git2` builds with `vendored-libgit2`, so no system libgit2 or OpenSSL is
+needed on any platform.
+
+#### Toolchain (all platforms)
+
+- Rust stable (1.80+) via `rustup`
 - Node.js 20+
 - pnpm 9+
 
@@ -225,6 +240,33 @@ of the generated installer — `target\release\bundle\nsis\OpenCherry_<version>_
 Double-click it to install. The installer is unsigned, so Windows SmartScreen
 may warn on first run; choose **More info → Run anyway**.
 
+### macOS disk image (`.dmg`)
+
+macOS builds produce a `.dmg` disk image. There are two ways to get one.
+
+**Download from CI** — every tagged release (`v*`) attaches Apple Silicon
+(`aarch64`) and Intel (`x86_64`) disk images to its GitHub Release. Manually
+triggering the **Release (macOS)** workflow (`workflow_dispatch`) builds both
+and uploads them as downloadable build artifacts.
+
+**Build locally on macOS** — install the Xcode Command Line Tools
+(`xcode-select --install`), Rust stable via `rustup`, and Node.js 20+ / pnpm 9+.
+Then, from the repo root:
+
+```bash
+./scripts/build-macos.sh
+```
+
+This runs `pnpm -C apps/desktop tauri build --bundles dmg` and prints the path
+of the generated image — `target/release/bundle/dmg/OpenCherry_<version>_<arch>.dmg`.
+Open it and drag **OpenCherry** to Applications. The app is unsigned and not
+notarized, so on first launch macOS Gatekeeper may block it; right-click the app
+→ **Open**, or allow it in **System Settings → Privacy & Security**.
+
+To cross-compile for both architectures from one machine, add the targets with
+`rustup target add aarch64-apple-darwin x86_64-apple-darwin` and set
+`OPENCHERRY_MAC_TARGET` (e.g. `OPENCHERRY_MAC_TARGET=universal-apple-darwin`).
+
 ## Testing
 
 The current codebase includes backend and frontend automated coverage for the
diff --git a/apps/desktop/src-tauri/tauri.conf.json b/apps/desktop/src-tauri/tauri.conf.json
index cce7830..2f5eab2 100644
--- a/apps/desktop/src-tauri/tauri.conf.json
+++ b/apps/desktop/src-tauri/tauri.conf.json
@@ -40,6 +40,14 @@
         "desktopTemplate": "templates/opencherry.desktop"
       }
     },
+    "macOS": {
+      "minimumSystemVersion": "10.15"
+    },
+    "windows": {
+      "nsis": {
+        "installMode": "currentUser"
+      }
+    },
     "icon": [
       "icons/32x32.png",
       "icons/64x64.png",
diff --git a/crates/opencherry_agents/src/lib.rs b/crates/opencherry_agents/src/lib.rs
index 8461197..60700cc 100644
--- a/crates/opencherry_agents/src/lib.rs
+++ b/crates/opencherry_agents/src/lib.rs
@@ -81,11 +81,54 @@ pub fn classify_status(cpu_usage: f32, os_status: sysinfo::ProcessStatus) -> Age
     }
 }
 
-/// Known interactive shell process names.
-const SHELL_PROCESS_NAMES: &[&str] = &["bash", "zsh", "fish", "sh", "dash", "tmux", "screen"];
+/// Known interactive shell / terminal multiplexer process names.
+///
+/// Includes Unix shells plus the common Windows shells and terminals, so the
+/// `require_shell_parent` heuristic works on every supported platform.
+const SHELL_PROCESS_NAMES: &[&str] = &[
+    // Unix shells & multiplexers
+    "bash",
+    "zsh",
+    "fish",
+    "sh",
+    "dash",
+    "tmux",
+    "screen",
+    // Windows shells & terminals
+    "cmd",
+    "powershell",
+    "pwsh",
+    "wt",
+    "windowsterminal",
+    "conhost",
+    "nu",
+];
+
+/// Windows executable extensions to strip before comparing process names.
+///
+/// On Windows `sysinfo` reports basenames such as `claude.exe` / `node.exe`,
+/// but agent rules are written with bare names (`claude`, `node`). Stripping
+/// the extension lets the same rule set match on every platform.
+const WINDOWS_EXE_SUFFIXES: &[&str] = &[".exe", ".cmd", ".bat", ".com"];
+
+/// Return `name` without a trailing Windows executable extension (if any).
+fn strip_exe_suffix(name: &str) -> &str {
+    for ext in WINDOWS_EXE_SUFFIXES {
+        if name.len() > ext.len() {
+            let (base, suffix) = name.split_at(name.len() - ext.len());
+            if suffix.eq_ignore_ascii_case(ext) {
+                return base;
+            }
+        }
+    }
+    name
+}
 
 fn is_shell_process(exe_basename: &str) -> bool {
-    SHELL_PROCESS_NAMES.contains(&exe_basename)
+    let name = strip_exe_suffix(exe_basename);
+    SHELL_PROCESS_NAMES
+        .iter()
+        .any(|shell| shell.eq_ignore_ascii_case(name))
 }
 
 /// Classify a process against a list of definitions.
@@ -94,7 +137,9 @@ fn classify(
     all_processes: &[ProcessSnapshot],
     definitions: &[AgentDefinition],
 ) -> Option<AgentKind> {
-    let exe_path_lc = process.exe_path.to_ascii_lowercase();
+    // Normalize Windows path separators so the Unix-style substrings below
+    // match on every platform.
+    let exe_path_lc = process.exe_path.to_ascii_lowercase().replace('\\', "/");
 
     // Universal exclusions (except for Antigravity CLI itself)
     if (exe_path_lc.contains("/.antigravity/extensions/")
@@ -120,22 +165,23 @@ fn matches_rule(
     process: &ProcessSnapshot,
     all_processes: &[ProcessSnapshot],
 ) -> bool {
-    // 1. Exe basename match
+    // 1. Exe basename match (extension-insensitive so `claude.exe` on Windows
+    //    matches a rule written as `claude`).
     if let Some(ref target) = rule.exe_basename {
-        if !process.exe_basename.eq_ignore_ascii_case(target)
-            && !process.process_name.eq_ignore_ascii_case(target)
-        {
+        let target = strip_exe_suffix(target);
+        let basename = strip_exe_suffix(&process.exe_basename);
+        let proc_name = strip_exe_suffix(&process.process_name);
+        if !basename.eq_ignore_ascii_case(target) && !proc_name.eq_ignore_ascii_case(target) {
             return false;
         }
     }
 
-    // 2. Exe path contains
+    // 2. Exe path contains (separator-insensitive: rules use `/`, Windows
+    //    paths use `\`).
     if let Some(ref target) = rule.exe_path_contains {
-        if !process
-            .exe_path
-            .to_ascii_lowercase()
-            .contains(&target.to_ascii_lowercase())
-        {
+        let haystack = process.exe_path.to_ascii_lowercase().replace('\\', "/");
+        let needle = target.to_ascii_lowercase().replace('\\', "/");
+        if !haystack.contains(&needle) {
             return false;
         }
     }
@@ -150,13 +196,11 @@ fn matches_rule(
         }
     }
 
-    // 4. Exclude path contains
+    // 4. Exclude path contains (separator-insensitive, see rule 2).
     if let Some(ref target) = rule.exclude_path_contains {
-        if process
-            .exe_path
-            .to_ascii_lowercase()
-            .contains(&target.to_ascii_lowercase())
-        {
+        let haystack = process.exe_path.to_ascii_lowercase().replace('\\', "/");
+        let needle = target.to_ascii_lowercase().replace('\\', "/");
+        if haystack.contains(&needle) {
             return false;
         }
     }
@@ -430,6 +474,58 @@ mod tests {
         );
     }
 
+    #[test]
+    fn classify_matches_windows_exe_basename() {
+        // On Windows sysinfo reports `opencode.exe`; a rule written as
+        // `opencode` must still match.
+        let defs = vec![def_opencode()];
+        let proc = snapshot(
+            123,
+            "C:\\Users\\me\\AppData\\opencode.exe",
+            "opencode.exe",
+            &["opencode.exe"],
+            false,
+        );
+        assert_eq!(
+            classify(&proc, std::slice::from_ref(&proc), &defs),
+            Some(AgentKind::OpenCode)
+        );
+    }
+
+    #[test]
+    fn is_shell_process_recognizes_windows_shells() {
+        assert!(is_shell_process("powershell.exe"));
+        assert!(is_shell_process("pwsh.exe"));
+        assert!(is_shell_process("cmd.exe"));
+        assert!(is_shell_process("bash"));
+        assert!(!is_shell_process("opencode.exe"));
+    }
+
+    #[test]
+    fn classify_matches_with_windows_shell_parent() {
+        let mut def = def_opencode();
+        def.rules[0].require_shell_parent = true;
+        let defs = vec![def];
+
+        let shell = snapshot(
+            100,
+            "C:\\Windows\\System32\\cmd.exe",
+            "cmd.exe",
+            &["cmd.exe"],
+            false,
+        );
+        let proc = snapshot_with_parent(
+            200,
+            Some(100),
+            "C:\\Users\\me\\opencode.exe",
+            "opencode.exe",
+            &["opencode.exe"],
+            false,
+        );
+        let procs = vec![shell, proc.clone()];
+        assert_eq!(classify(&proc, &procs, &defs), Some(AgentKind::OpenCode));
+    }
+
     #[test]
     fn classify_respects_shell_parent_requirement() {
         let mut def = def_opencode();
diff --git a/crates/opencherry_repo/src/lib.rs b/crates/opencherry_repo/src/lib.rs
index 53fab83..b7b8214 100644
--- a/crates/opencherry_repo/src/lib.rs
+++ b/crates/opencherry_repo/src/lib.rs
@@ -766,6 +766,15 @@ mod tests {
             let path = root.path().join("repo");
             fs::create_dir_all(&path).unwrap();
             let repo = Repository::init(&path).unwrap();
+            // Pin line-ending behavior so tests are deterministic across
+            // platforms. Windows CI runners default to `core.autocrlf=true`
+            // globally, which would rewrite checked-out `\n` content as `\r\n`
+            // and break exact-content assertions (e.g. in discard_files).
+            {
+                let mut config = repo.config().unwrap();
+                config.set_bool("core.autocrlf", false).unwrap();
+                config.set_str("core.eol", "lf").unwrap();
+            }
             let this = Self {
                 _root: root,
                 path,
diff --git a/justfile b/justfile
index 70db0d5..eeff2f1 100644
--- a/justfile
+++ b/justfile
@@ -29,6 +29,14 @@ check:
 build-deb:
     ./scripts/build-deb.sh
 
+# Build the production .dmg disk image (macOS)
+build-macos:
+    ./scripts/build-macos.sh
+
+# Build the production .exe installer (Windows; run from PowerShell)
+build-windows:
+    pwsh ./scripts/build-windows.ps1
+
 # List all available commands
 list:
     @just --list
diff --git a/scripts/build-macos.sh b/scripts/build-macos.sh
new file mode 100755
index 0000000..4381026
--- /dev/null
+++ b/scripts/build-macos.sh
@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+#
+# Build the OpenCherry desktop app as a macOS disk image (.dmg).
+#
+# Produces a single, unsigned, non-notarized disk image suitable for local
+# install on macOS. No signing, no store — just `tauri build`.
+#
+# Usage:   ./scripts/build-macos.sh
+# Output:  target/release/bundle/dmg/*.dmg  (Cargo workspace target dir)
+#
+# Requirements:
+#   - macOS with the Xcode Command Line Tools (`xcode-select --install`).
+#   - Rust stable via rustup.
+#   - Node.js 20+ and pnpm 9+.
+# git2 builds with `vendored-libgit2`, so no system libgit2/OpenSSL is needed.
+#
+# Apple Silicon vs Intel: by default this builds for the host architecture.
+# Set OPENCHERRY_MAC_TARGET to a Rust target triple to cross-compile, e.g.
+#   OPENCHERRY_MAC_TARGET=universal-apple-darwin ./scripts/build-macos.sh
+# (requires the matching `rustup target add` first; `universal-apple-darwin`
+# produces a fat binary for both architectures).
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$repo_root"
+
+if [[ "$(uname -s)" != "Darwin" ]]; then
+  echo "==> ERROR: build-macos.sh must run on macOS (uname -s = $(uname -s))." >&2
+  exit 1
+fi
+
+tauri_args=(--bundles dmg)
+if [[ -n "${OPENCHERRY_MAC_TARGET:-}" ]]; then
+  echo "==> Building for target: ${OPENCHERRY_MAC_TARGET}"
+  tauri_args+=(--target "${OPENCHERRY_MAC_TARGET}")
+fi
+
+echo "==> Building OpenCherry .dmg (release)…"
+pnpm -C apps/desktop tauri build "${tauri_args[@]}"
+
+# This is a Cargo workspace, so the bundle lands in the workspace-root target/.
+# With an explicit --target the path is nested under the triple.
+if [[ -n "${OPENCHERRY_MAC_TARGET:-}" ]]; then
+  dmg_dir="target/${OPENCHERRY_MAC_TARGET}/release/bundle/dmg"
+else
+  dmg_dir="target/release/bundle/dmg"
+fi
+
+# Resolve the freshly built image by glob so version bumps don't break this.
+dmg_file="$(ls -t "$dmg_dir"/*.dmg 2>/dev/null | head -n 1 || true)"
+
+if [[ -z "$dmg_file" ]]; then
+  echo "==> ERROR: no .dmg found in $dmg_dir" >&2
+  exit 1
+fi
+
+echo
+echo "==> Done. Disk image built:"
+echo "    $repo_root/$dmg_file"
+echo
+echo "    Install by opening the .dmg and dragging OpenCherry to Applications."
+echo "    The app is unsigned, so on first launch macOS Gatekeeper may block it:"
+echo "    right-click the app → Open, or allow it in System Settings → Privacy."