diff --git a/pkg/env/env.go b/pkg/env/env.go
index ed5e407..27200c8 100644
--- a/pkg/env/env.go
+++ b/pkg/env/env.go
@@ -106,12 +106,14 @@ func All() map[string]string {
 	return m
 }
 
-// Format returns the full process environment as NAME=VALUE lines, suitable
-// for serving as ollie/env.
+// Format returns the managed environment variables as NAME=VALUE lines,
+// suitable for serving as ollie/env.
 func Format() []byte {
 	var sb strings.Builder
-	for _, pair := range os.Environ() {
-		fmt.Fprintf(&sb, "%s\n", pair)
+	for _, k := range managed {
+		if v := os.Getenv(k); v != "" {
+			fmt.Fprintf(&sb, "%s=%s\n", k, v)
+		}
 	}
 	return []byte(sb.String())
 }
diff --git a/pkg/env/env_test.go b/pkg/env/env_test.go
index b47f2e6..75a1fda 100644
--- a/pkg/env/env_test.go
+++ b/pkg/env/env_test.go
@@ -45,9 +45,9 @@ func TestAll(t *testing.T) {
 }
 
 func TestFormat(t *testing.T) {
-	t.Setenv("OLLIE_TEST_FMT", "xyz")
+	t.Setenv("OLLIE_TMP_PATH", "/tmp/test-fmt")
 	out := string(Format())
-	if !strings.Contains(out, "OLLIE_TEST_FMT=xyz") {
+	if !strings.Contains(out, "OLLIE_TMP_PATH=/tmp/test-fmt") {
 		t.Errorf("Format() missing expected var, got:\n%s", out)
 	}
 	// Every line should be NAME=VALUE\n