diff --git a/.github/workflows/app-binaries.yml b/.github/workflows/app-binaries.yml
new file mode 100644
index 0000000000..9bdf9a2714
--- /dev/null
+++ b/.github/workflows/app-binaries.yml
@@ -0,0 +1,41 @@
+name: app-binaries
+# Regression gate: build every binary the macOS Studio app ships, each with its
+# required-features. `cargo build --workspace` skips required-features bins, so
+# this is the only CI that compiles chat_metal / eval_perplexity / train_grad_full
+# / generate_lora / embed with the features the app actually builds them with.
+# See scripts/build-app-bins.sh for the rationale and the two regressions that
+# motivated it.
+
+on:
+  pull_request:
+    branches: [main]
+    paths:
+      - 'crates/**'
+      - 'scripts/build-app-bins.sh'
+      - '.github/workflows/app-binaries.yml'
+  push:
+    branches: [main]
+    paths:
+      - 'crates/**'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+  CARGO_INCREMENTAL: '0'
+
+jobs:
+  build-app-bins:
+    name: build app-shipped binaries
+    runs-on: macos-latest
+    timeout-minutes: 45
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@1.94.1
+      - uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: app-binaries
+      - name: Build all app-shipped binaries (required-features included)
+        run: ./scripts/build-app-bins.sh
diff --git a/scripts/build-app-bins.sh b/scripts/build-app-bins.sh
new file mode 100755
index 0000000000..be398d26d6
--- /dev/null
+++ b/scripts/build-app-bins.sh
@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+#
+# Build every binary the macOS Studio app ships (apps/macos/scripts/package-app.sh),
+# each with its required-features.
+#
+# This is the regression gate that `cargo build --workspace` cannot provide:
+# --workspace (even with --all-targets) silently SKIPS any [[bin]] that declares
+# `required-features` unless those features are explicitly enabled. So a
+# required-features binary can stop compiling and never trip fmt / clippy / test
+# / build CI — the break only surfaces when the app is packaged.
+#
+# Two real regressions slipped through exactly this gap and were caught only at
+# packaging time:
+#   - train_grad_full  E0063  (missing GDN gradient fields under train-backward)
+#   - generate_lora    E0599  (generate_streaming method not in scope)
+#
+# Keep this binary list in sync with apps/macos/scripts/package-app.sh.
+
+set -uo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$REPO_ROOT"
+
+FAIL=0
+build_bin() {
+    echo ""
+    echo "==> cargo build --release $*"
+    if ! cargo build --release "$@"; then
+        echo "!! FAILED: cargo build --release $*"
+        FAIL=1
+    fi
+}
+
+# lattice-inference — default features (already covered by --workspace, built
+# here too so the gate reflects the full app binary set).
+for BIN in quantize_q4 quantize_quarot lattice qwen35_generate; do
+    build_bin -p lattice-inference --bin "$BIN"
+done
+
+# required-features binaries — the ones `cargo build --workspace` silently skips.
+build_bin -p lattice-tune      --bin train_grad_full --features train-backward
+build_bin -p lattice-tune      --bin generate_lora   --features safetensors,inference-hook
+build_bin -p lattice-inference --bin eval_perplexity --features f16,metal-gpu
+build_bin -p lattice-inference --bin chat_metal      --features f16,metal-gpu
+
+# lattice-embed — `native` is a default feature, so no explicit --features.
+build_bin -p lattice-embed     --bin embed
+
+if [ "$FAIL" -ne 0 ]; then
+    echo ""
+    echo "ERROR: one or more app-shipped binaries failed to build."
+    echo "The macOS Studio app would fail to package. Fix before merging."
+    exit 1
+fi
+echo ""
+echo "OK: all app-shipped binaries built."