diff --git a/internal/recipe/export_test.go b/internal/recipe/export_test.go
new file mode 100644
index 0000000..bff90b4
--- /dev/null
+++ b/internal/recipe/export_test.go
@@ -0,0 +1,4 @@
+package recipe
+
+// VerifyRPackagesCmd exposes verifyRPackagesCmd to the external test package.
+func VerifyRPackagesCmd() string { return verifyRPackagesCmd() }
diff --git a/internal/recipe/r.go b/internal/recipe/r.go
index 9390986..ceac907 100644
--- a/internal/recipe/r.go
+++ b/internal/recipe/r.go
@@ -36,6 +36,10 @@ type rPackage struct {
 	srcDir string // e.g. "source-forecast-latest"
 }
 
+// rExplicitDeps are packages that devtools used to bundle as freebies. They are
+// installed up front and stay in the artifact as R app runtime dependencies.
+var rExplicitDeps = []string{"cli", "curl", "lifecycle", "R6", "rlang", "withr", "processx", "callr", "stringr"}
+
 // rSubDeps lists the R packages to install, in the same order as the Ruby builder:
 // Rserve, forecast, shiny, plumber.
 var rSubDeps = []rPackage{
@@ -98,13 +102,20 @@ func (r *RRecipe) Build(ctx context.Context, s *stack.Stack, src *source.Input,
 	// the remotes package separately. Use remotes directly instead.
 	// We also explicitly install packages that devtools used to bundle as freebies
 	// (stringr, cli, etc.) to avoid breaking R apps that depend on them implicitly.
+	//
+	// fs >= 2.0.0 (pulled in by shiny via sass/bslib) needs libuv headers, which the
+	// stacks do not ship. USE_BUNDLED_LIBUV makes it build its vendored libuv instead.
+	rEnv := map[string]string{"USE_BUNDLED_LIBUV": "1"}
 	remotesCmd := `/usr/local/lib/R/bin/R --vanilla -e 'install.packages("remotes", repos="https://cran.r-project.org")'`
-	if err := run.Run("sh", "-c", remotesCmd); err != nil {
+	if err := run.RunWithEnv(rEnv, "sh", "-c", remotesCmd); err != nil {
 		return fmt.Errorf("r: installing remotes: %w", err)
 	}
 
-	depsCmd := `/usr/local/lib/R/bin/R --vanilla -e 'install.packages(c("cli", "curl", "lifecycle", "R6", "rlang", "withr", "processx", "callr", "stringr"), repos="https://cran.r-project.org")'`
-	if err := run.Run("sh", "-c", depsCmd); err != nil {
+	depsCmd := fmt.Sprintf(
+		`/usr/local/lib/R/bin/R --vanilla -e 'install.packages(c(%s), repos="https://cran.r-project.org")'`,
+		quoteRNames(`"`, rExplicitDeps),
+	)
+	if err := run.RunWithEnv(rEnv, "sh", "-c", depsCmd); err != nil {
 		return fmt.Errorf("r: installing explicit r dependencies: %w", err)
 	}
 
@@ -129,7 +140,7 @@ func (r *RRecipe) Build(ctx context.Context, s *stack.Stack, src *source.Input,
 			`/usr/local/lib/R/bin/R --vanilla -e "require('remotes'); remotes::install_version('%s', '%s', repos='https://cran.r-project.org', type='source', dependencies=TRUE)"`,
 			pkg.name, pkgVersion,
 		)
-		if err := run.Run("sh", "-c", rCmd); err != nil {
+		if err := run.RunWithEnv(rEnv, "sh", "-c", rCmd); err != nil {
 			return fmt.Errorf("r: installing R package %s: %w", pkg.name, err)
 		}
 
@@ -142,6 +153,12 @@ func (r *RRecipe) Build(ctx context.Context, s *stack.Stack, src *source.Input,
 		}
 	}
 
+	// R exits 0 when install.packages fails for a dependency, so verify the
+	// packages (and the dependencies that the buildpack tests rely on) are present.
+	if err := run.Run("sh", "-c", verifyRPackagesCmd()); err != nil {
+		return fmt.Errorf("r: verifying installed R packages: %w", err)
+	}
+
 	// Step 7: Remove remotes after use. The explicitly pre-installed packages
 	// (cli, curl, stringr, etc.) are intentionally left in the artifact — they
 	// are R app runtime dependencies that devtools used to bundle as freebies.
@@ -178,6 +195,31 @@ func (r *RRecipe) Build(ctx context.Context, s *stack.Stack, src *source.Input,
 	return nil
 }
 
+// quoteRNames wraps each name in the given quote character and joins them
+// into the body of an R c(...) call.
+func quoteRNames(quote string, names []string) string {
+	quoted := make([]string, len(names))
+	for i, n := range names {
+		quoted[i] = quote + n + quote
+	}
+	return strings.Join(quoted, ", ")
+}
+
+// verifyRPackagesCmd returns an R command that exits non-zero if fs, the
+// explicitly installed dependencies or the sub-dependency packages cannot be
+// loaded. Loading (not just being listed as installed) also catches a broken
+// native build such as fs against the bundled libuv.
+func verifyRPackagesCmd() string {
+	names := append([]string{"fs"}, rExplicitDeps...)
+	for _, pkg := range rSubDeps {
+		names = append(names, pkg.name)
+	}
+	return fmt.Sprintf(
+		`/usr/local/lib/R/bin/R --vanilla -e "pkgs <- c(%s); missing <- pkgs[!vapply(pkgs, requireNamespace, logical(1), quietly=TRUE)]; if (length(missing) > 0) stop('missing R packages: ', paste(missing, collapse=', '))"`,
+		quoteRNames("'", names),
+	)
+}
+
 // formatRserveVersion converts "1.8.14" → "1.8-14"
 // (first two dot-separated parts joined by '.', remainder joined by '-').
 func formatRserveVersion(v string) string {
diff --git a/internal/recipe/recipe_compiled_test.go b/internal/recipe/recipe_compiled_test.go
index c0acb3c..2fbc711 100644
--- a/internal/recipe/recipe_compiled_test.go
+++ b/internal/recipe/recipe_compiled_test.go
@@ -843,6 +843,74 @@ func TestRRecipeRemovesRemotes(t *testing.T) {
 		"should call remove.packages(\"remotes\") after package installs")
 }
 
+func TestRRecipeUsesBundledLibuvForPackageInstalls(t *testing.T) {
+	useTempWorkDir(t)
+	writeRSubDepFiles(t)
+
+	r := &recipe.RRecipe{Fetcher: newFakeFetcher()}
+	run := runner.NewFakeRunner()
+	s := newCompiledStack(t)
+	s.AptPackages["r_build"] = []string{"r-base"}
+	src := newInput("r", "4.3.1", "https://cran.r-project.org/src/base/R-4.3.1.tar.gz")
+
+	require.NoError(t, r.Build(context.Background(), s, src, run, &output.OutData{}))
+
+	installs := 0
+	for _, c := range run.Calls {
+		joined := strings.Join(c.Args, " ")
+		if c.Name == "sh" && (strings.Contains(joined, "install.packages(") || strings.Contains(joined, "install_version")) {
+			installs++
+			assert.Equal(t, "1", c.Env["USE_BUNDLED_LIBUV"], "package install must set USE_BUNDLED_LIBUV: %s", joined)
+		}
+	}
+	assert.Greater(t, installs, 0, "expected package install calls")
+}
+
+func TestRRecipeVerifiesPackagesBeforeRemovingRemotes(t *testing.T) {
+	useTempWorkDir(t)
+	writeRSubDepFiles(t)
+
+	r := &recipe.RRecipe{Fetcher: newFakeFetcher()}
+	run := runner.NewFakeRunner()
+	s := newCompiledStack(t)
+	s.AptPackages["r_build"] = []string{"r-base"}
+	src := newInput("r", "4.3.1", "https://cran.r-project.org/src/base/R-4.3.1.tar.gz")
+
+	require.NoError(t, r.Build(context.Background(), s, src, run, &output.OutData{}))
+
+	verifyIdx, removeIdx := -1, -1
+	for i, c := range run.Calls {
+		joined := strings.Join(c.Args, " ")
+		if c.Name == "sh" && strings.Contains(joined, "requireNamespace") {
+			verifyIdx = i
+			for _, pkg := range []string{"'fs'", "'shiny'", "'forecast'", "'plumber'", "'Rserve'", "'cli'", "'curl'", "'processx'", "'stringr'"} {
+				assert.Contains(t, joined, pkg)
+			}
+		}
+		if c.Name == "sh" && strings.Contains(joined, `remove.packages("remotes")`) {
+			removeIdx = i
+		}
+	}
+	require.True(t, verifyIdx >= 0, "package verification call not found")
+	assert.Less(t, verifyIdx, removeIdx)
+}
+
+func TestRRecipeFailsWhenPackageVerificationFails(t *testing.T) {
+	useTempWorkDir(t)
+	writeRSubDepFiles(t)
+
+	s := newCompiledStack(t)
+	s.AptPackages["r_build"] = []string{"r-base"}
+	src := newInput("r", "4.3.1", "https://cran.r-project.org/src/base/R-4.3.1.tar.gz")
+
+	run := runner.NewFakeRunner()
+	verifyKey := "sh -c " + recipe.VerifyRPackagesCmd()
+	run.ErrorMap = map[string]error{verifyKey: fmt.Errorf("missing R packages: fs")}
+	err := (&recipe.RRecipe{Fetcher: newFakeFetcher()}).Build(context.Background(), s, src, run, &output.OutData{})
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "verifying installed R packages")
+}
+
 func TestRserveVersionFormatting(t *testing.T) {
 	useTempWorkDir(t)
 	writeRSubDepFiles(t)