diff --git a/.github/workflows/install-scripts-local.yml b/.github/workflows/install-scripts-local.yml
new file mode 100644
index 00000000..660a4f47
--- /dev/null
+++ b/.github/workflows/install-scripts-local.yml
@@ -0,0 +1,129 @@
+name: Install Scripts (Local Build)
+
+on:
+  pull_request:
+    branches: [main]
+  push:
+    branches: [main]
+  merge_group:
+    branches: [main]
+
+jobs:
+  install-local-unix:
+    name: Local install.sh on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Build git-ai
+        run: cargo build --release --bin git-ai
+
+      - name: Prepare test home and fake Claude Code
+        run: |
+          TEST_HOME="$RUNNER_TEMP/git-ai-home"
+          mkdir -p "$TEST_HOME/.config/fish" "$TEST_HOME/.claude"
+          touch "$TEST_HOME/.bashrc" "$TEST_HOME/.zshrc" "$TEST_HOME/.config/fish/config.fish"
+          echo "HOME=$TEST_HOME" >> "$GITHUB_ENV"
+
+          BIN_DIR="$RUNNER_TEMP/fake-bin"
+          mkdir -p "$BIN_DIR"
+          cat > "$BIN_DIR/claude" <<'EOF'
+          #!/bin/sh
+          echo "2.0.0 (Claude Code)"
+          EOF
+          chmod +x "$BIN_DIR/claude"
+          echo "$BIN_DIR" >> "$GITHUB_PATH"
+
+      - name: Run install.sh with local binary
+        env:
+          GIT_AI_LOCAL_BINARY: ${{ github.workspace }}/target/release/git-ai
+        run: |
+          chmod +x ./install.sh
+          ./install.sh
+
+      - name: Verify shell configs and Claude hooks
+        run: |
+          INSTALL_DIR="$HOME/.git-ai/bin"
+          test -x "$INSTALL_DIR/git-ai"
+          grep -F "$INSTALL_DIR" "$HOME/.bashrc"
+          grep -F "$INSTALL_DIR" "$HOME/.zshrc"
+          grep -F "fish_add_path -g \"$INSTALL_DIR\"" "$HOME/.config/fish/config.fish"
+          grep -F "checkpoint claude" "$HOME/.claude/settings.json"
+
+  install-local-windows:
+    name: Local install.ps1 on windows-latest
+    runs-on: windows-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Build git-ai
+        run: cargo build --release --bin git-ai
+
+      - name: Prepare test home and fake Claude Code
+        shell: pwsh
+        run: |
+          $testHome = Join-Path $env:RUNNER_TEMP "git-ai-home"
+          New-Item -ItemType Directory -Force -Path $testHome | Out-Null
+          $homeDrive = [System.IO.Path]::GetPathRoot($testHome).TrimEnd('\')
+          $homePath = $testHome.Substring($homeDrive.Length)
+          Add-Content -Path $env:GITHUB_ENV -Value "TEST_HOME=$testHome"
+          Add-Content -Path $env:GITHUB_ENV -Value "TEST_HOME_DRIVE=$homeDrive"
+          Add-Content -Path $env:GITHUB_ENV -Value "TEST_HOME_PATH=$homePath"
+
+          $claudeDir = Join-Path $testHome ".claude"
+          New-Item -ItemType Directory -Force -Path $claudeDir | Out-Null
+
+          $binDir = Join-Path $env:RUNNER_TEMP "fake-bin"
+          New-Item -ItemType Directory -Force -Path $binDir | Out-Null
+          $claudeCmd = Join-Path $binDir "claude.cmd"
+          "@echo 2.0.0 (Claude Code)" | Out-File -FilePath $claudeCmd -Encoding ASCII -Force
+          Add-Content -Path $env:GITHUB_PATH -Value $binDir
+
+      - name: Run install.ps1 with local binary
+        shell: pwsh
+        env:
+          GIT_AI_LOCAL_BINARY: ${{ github.workspace }}\target\release\git-ai.exe
+          HOME: ${{ env.TEST_HOME }}
+          USERPROFILE: ${{ env.TEST_HOME }}
+          HOMEDRIVE: ${{ env.TEST_HOME_DRIVE }}
+          HOMEPATH: ${{ env.TEST_HOME_PATH }}
+        run: |
+          Set-ExecutionPolicy -ExecutionPolicy Bypass -Scope Process -Force
+          ./install.ps1
+
+      - name: Verify Claude hooks
+        shell: pwsh
+        env:
+          HOME: ${{ env.TEST_HOME }}
+          USERPROFILE: ${{ env.TEST_HOME }}
+          HOMEDRIVE: ${{ env.TEST_HOME_DRIVE }}
+          HOMEPATH: ${{ env.TEST_HOME_PATH }}
+        run: |
+          $installDir = Join-Path $env:USERPROFILE ".git-ai\bin"
+          if (-not (Test-Path -LiteralPath (Join-Path $installDir "git-ai.exe"))) { throw "git-ai.exe not installed" }
+          $settings = Join-Path $env:USERPROFILE ".claude\settings.json"
+          if (-not (Select-String -Path $settings -Pattern "checkpoint claude")) { throw "Claude hooks not configured" }
diff --git a/.github/workflows/install-scripts-nightly.yml b/.github/workflows/install-scripts-nightly.yml
new file mode 100644
index 00000000..32282c37
--- /dev/null
+++ b/.github/workflows/install-scripts-nightly.yml
@@ -0,0 +1,93 @@
+name: Install Scripts (Nightly)
+
+on:
+  schedule:
+    - cron: "0 3 * * *"
+  workflow_dispatch:
+
+jobs:
+  install-nightly-unix:
+    name: Nightly install.sh on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+
+    steps:
+      - name: Prepare test home and fake Claude Code
+        run: |
+          TEST_HOME="$RUNNER_TEMP/git-ai-home"
+          mkdir -p "$TEST_HOME/.config/fish" "$TEST_HOME/.claude"
+          touch "$TEST_HOME/.bashrc" "$TEST_HOME/.zshrc" "$TEST_HOME/.config/fish/config.fish"
+          echo "HOME=$TEST_HOME" >> "$GITHUB_ENV"
+
+          BIN_DIR="$RUNNER_TEMP/fake-bin"
+          mkdir -p "$BIN_DIR"
+          cat > "$BIN_DIR/claude" <<'EOF'
+          #!/bin/sh
+          echo "2.0.0 (Claude Code)"
+          EOF
+          chmod +x "$BIN_DIR/claude"
+          echo "$BIN_DIR" >> "$GITHUB_PATH"
+
+      - name: Run install.sh from usegitai.com
+        run: curl -fsSL https://usegitai.com/install.sh | bash
+
+      - name: Verify shell configs and Claude hooks
+        run: |
+          INSTALL_DIR="$HOME/.git-ai/bin"
+          test -x "$INSTALL_DIR/git-ai"
+          grep -F "$INSTALL_DIR" "$HOME/.bashrc"
+          grep -F "$INSTALL_DIR" "$HOME/.zshrc"
+          grep -F "fish_add_path -g \"$INSTALL_DIR\"" "$HOME/.config/fish/config.fish"
+          grep -F "checkpoint claude" "$HOME/.claude/settings.json"
+
+  install-nightly-windows:
+    name: Nightly install.ps1 on windows-latest
+    runs-on: windows-latest
+
+    steps:
+      - name: Prepare test home and fake Claude Code
+        shell: pwsh
+        run: |
+          $testHome = Join-Path $env:RUNNER_TEMP "git-ai-home"
+          New-Item -ItemType Directory -Force -Path $testHome | Out-Null
+          $homeDrive = [System.IO.Path]::GetPathRoot($testHome).TrimEnd('\')
+          $homePath = $testHome.Substring($homeDrive.Length)
+          Add-Content -Path $env:GITHUB_ENV -Value "TEST_HOME=$testHome"
+          Add-Content -Path $env:GITHUB_ENV -Value "TEST_HOME_DRIVE=$homeDrive"
+          Add-Content -Path $env:GITHUB_ENV -Value "TEST_HOME_PATH=$homePath"
+
+          $claudeDir = Join-Path $testHome ".claude"
+          New-Item -ItemType Directory -Force -Path $claudeDir | Out-Null
+
+          $binDir = Join-Path $env:RUNNER_TEMP "fake-bin"
+          New-Item -ItemType Directory -Force -Path $binDir | Out-Null
+          $claudeCmd = Join-Path $binDir "claude.cmd"
+          "@echo 2.0.0 (Claude Code)" | Out-File -FilePath $claudeCmd -Encoding ASCII -Force
+          Add-Content -Path $env:GITHUB_PATH -Value $binDir
+
+      - name: Run install.ps1 from usegitai.com
+        shell: pwsh
+        env:
+          HOME: ${{ env.TEST_HOME }}
+          USERPROFILE: ${{ env.TEST_HOME }}
+          HOMEDRIVE: ${{ env.TEST_HOME_DRIVE }}
+          HOMEPATH: ${{ env.TEST_HOME_PATH }}
+        run: |
+          Set-ExecutionPolicy -ExecutionPolicy Bypass -Scope Process -Force
+          Invoke-WebRequest -UseBasicParsing https://usegitai.com/install.ps1 | Invoke-Expression
+
+      - name: Verify Claude hooks
+        shell: pwsh
+        env:
+          HOME: ${{ env.TEST_HOME }}
+          USERPROFILE: ${{ env.TEST_HOME }}
+          HOMEDRIVE: ${{ env.TEST_HOME_DRIVE }}
+          HOMEPATH: ${{ env.TEST_HOME_PATH }}
+        run: |
+          $installDir = Join-Path $env:USERPROFILE ".git-ai\bin"
+          if (-not (Test-Path -LiteralPath (Join-Path $installDir "git-ai.exe"))) { throw "git-ai.exe not installed" }
+          $settings = Join-Path $env:USERPROFILE ".claude\settings.json"
+          if (-not (Select-String -Path $settings -Pattern "checkpoint claude")) { throw "Claude hooks not configured" }
diff --git a/install.ps1 b/install.ps1
index 9923eb44..8d5b5396 100644
--- a/install.ps1
+++ b/install.ps1
@@ -272,8 +272,10 @@ $os = 'windows'
 $binaryName = "git-ai-$os-$arch"
 
 # Determine release tag
-# Priority: 1. Pinned version (for release builds), 2. Environment variable, 3. "latest"
-if ($PinnedVersion -ne '__VERSION_PLACEHOLDER__') {
+# Priority: 1. Local binary override, 2. Pinned version (for release builds), 3. Environment variable, 4. "latest"
+if (-not [string]::IsNullOrWhiteSpace($env:GIT_AI_LOCAL_BINARY)) {
+    $releaseTag = 'local'
+} elseif ($PinnedVersion -ne '__VERSION_PLACEHOLDER__') {
     # Version-pinned install script from a release
     $releaseTag = $PinnedVersion
     $downloadUrlExe = "https://usegitai.com/worker/releases/download/$releaseTag/$binaryName.exe"
@@ -311,7 +313,14 @@ function Try-Download {
 
 # Track which download URL succeeded for checksum verification
 $downloadedBinaryName = $null
-if (Try-Download -Url $downloadUrlExe) {
+if (-not [string]::IsNullOrWhiteSpace($env:GIT_AI_LOCAL_BINARY)) {
+    if (-not (Test-Path -LiteralPath $env:GIT_AI_LOCAL_BINARY)) {
+        Remove-Item -Force -ErrorAction SilentlyContinue $tmpFile
+        Write-ErrorAndExit "Local binary not found at $($env:GIT_AI_LOCAL_BINARY)"
+    }
+    Copy-Item -Force -Path $env:GIT_AI_LOCAL_BINARY -Destination $tmpFile
+    $downloadedBinaryName = "$binaryName.exe"
+} elseif (Try-Download -Url $downloadUrlExe) {
     $downloadedBinaryName = "$binaryName.exe"
 } elseif (Try-Download -Url $downloadUrlNoExt) {
     $downloadedBinaryName = $binaryName
diff --git a/install.sh b/install.sh
index 0107dcb6..3bd9d8b8 100755
--- a/install.sh
+++ b/install.sh
@@ -216,8 +216,11 @@ esac
 BINARY_NAME="git-ai-${OS}-${ARCH}"
 
 # Determine release tag
-# Priority: 1. Pinned version (for release builds), 2. Environment variable, 3. "latest"
-if [ "$PINNED_VERSION" != "__VERSION_PLACEHOLDER__" ]; then
+# Priority: 1. Local binary override, 2. Pinned version (for release builds), 3. Environment variable, 4. "latest"
+if [ -n "${GIT_AI_LOCAL_BINARY:-}" ]; then
+    RELEASE_TAG="local"
+    DOWNLOAD_URL=""
+elif [ "$PINNED_VERSION" != "__VERSION_PLACEHOLDER__" ]; then
     # Version-pinned install script from a release
     RELEASE_TAG="$PINNED_VERSION"
     DOWNLOAD_URL="https://usegitai.com/worker/releases/download/${RELEASE_TAG}/${BINARY_NAME}"
@@ -238,11 +241,19 @@ INSTALL_DIR="$HOME/.git-ai/bin"
 mkdir -p "$INSTALL_DIR"
 
 # Download and install
-echo "Downloading git-ai (release: ${RELEASE_TAG})..."
 TMP_FILE="${INSTALL_DIR}/git-ai.tmp.$$"
-if ! curl --fail --location --silent --show-error -o "$TMP_FILE" "$DOWNLOAD_URL"; then
-    rm -f "$TMP_FILE" 2>/dev/null || true
-    error "Failed to download binary (HTTP error)"
+if [ -n "${GIT_AI_LOCAL_BINARY:-}" ]; then
+    echo "Using local git-ai binary (release: ${RELEASE_TAG})..."
+    if [ ! -f "$GIT_AI_LOCAL_BINARY" ]; then
+        error "Local binary not found at $GIT_AI_LOCAL_BINARY"
+    fi
+    cp "$GIT_AI_LOCAL_BINARY" "$TMP_FILE"
+else
+    echo "Downloading git-ai (release: ${RELEASE_TAG})..."
+    if ! curl --fail --location --silent --show-error -o "$TMP_FILE" "$DOWNLOAD_URL"; then
+        rm -f "$TMP_FILE" 2>/dev/null || true
+        error "Failed to download binary (HTTP error)"
+    fi
 fi
 
 # Basic validation: ensure file is not empty
diff --git a/src/config.rs b/src/config.rs
index 61a03186..86c9b452 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -9,6 +9,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::feature_flags::FeatureFlags;
 use crate::git::repository::Repository;
+use crate::mdm::utils::home_dir;
 
 #[cfg(any(test, feature = "test-support"))]
 use std::sync::RwLock;
@@ -681,8 +682,7 @@ fn load_file_config() -> Option<FileConfig> {
 }
 
 fn config_file_path() -> Option<PathBuf> {
-    let home = dirs::home_dir()?;
-    Some(home.join(".git-ai").join("config.json"))
+    Some(home_dir().join(".git-ai").join("config.json"))
 }
 
 /// Public accessor for config file path
@@ -693,16 +693,7 @@ pub fn config_file_path_public() -> Option<PathBuf> {
 
 /// Returns the path to the git-ai base directory (~/.git-ai)
 pub fn git_ai_dir_path() -> Option<PathBuf> {
-    #[cfg(windows)]
-    {
-        let home = env::var("USERPROFILE").ok()?;
-        Some(Path::new(&home).join(".git-ai"))
-    }
-    #[cfg(not(windows))]
-    {
-        let home = env::var("HOME").ok()?;
-        Some(Path::new(&home).join(".git-ai"))
-    }
+    Some(home_dir().join(".git-ai"))
 }
 
 /// Returns the path to the internal state directory (~/.git-ai/internal)
diff --git a/src/mdm/utils.rs b/src/mdm/utils.rs
index 374802d3..647db9f4 100644
--- a/src/mdm/utils.rs
+++ b/src/mdm/utils.rs
@@ -107,7 +107,41 @@ pub fn is_github_codespaces() -> bool {
 
 /// Get the user's home directory
 pub fn home_dir() -> PathBuf {
-    dirs::home_dir().unwrap_or_else(|| PathBuf::from("."))
+    #[cfg(windows)]
+    {
+        if let Ok(userprofile) = std::env::var("USERPROFILE") {
+            if !userprofile.is_empty() {
+                return PathBuf::from(userprofile);
+            }
+        }
+
+        if let (Ok(home_drive), Ok(home_path)) =
+            (std::env::var("HOMEDRIVE"), std::env::var("HOMEPATH"))
+        {
+            if !home_drive.is_empty() && !home_path.is_empty() {
+                return PathBuf::from(format!("{}{}", home_drive, home_path));
+            }
+        }
+
+        if let Ok(home) = std::env::var("HOME")
+            && !home.is_empty()
+        {
+            return PathBuf::from(home);
+        }
+
+        return dirs::home_dir().unwrap_or_else(|| PathBuf::from("."));
+    }
+
+    #[cfg(not(windows))]
+    {
+        if let Ok(home) = std::env::var("HOME")
+            && !home.is_empty()
+        {
+            return PathBuf::from(home);
+        }
+
+        dirs::home_dir().unwrap_or_else(|| PathBuf::from("."))
+    }
 }
 
 /// Write data to a file atomically (write to temp, then rename)