diff --git a/Cargo.toml b/Cargo.toml
index 2324b945..81bbfdb9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,9 @@ e2e = []
 cli = []
 plugins-only = []
 builtin-core = []
+## JIT-direct only mode: disable legacy VM-arg fallback and plugin-builtins branches
+## (keeps code compiling; VM-integrated JIT paths remain but are inert)
+jit-direct-only = []
 gui = ["dep:egui", "dep:eframe", "dep:egui_extras", "dep:image"]
 gui-examples = ["gui"]
 all-examples = ["gui-examples"]
diff --git a/src/jit/policy/invoke.rs b/src/jit/policy/invoke.rs
index 6cd3bf3c..f2277c46 100644
--- a/src/jit/policy/invoke.rs
+++ b/src/jit/policy/invoke.rs
@@ -11,7 +11,10 @@ pub enum InvokeDecision {
 }
 
 fn use_plugin_builtins() -> bool {
-    std::env::var("NYASH_USE_PLUGIN_BUILTINS").ok().as_deref() == Some("1")
+    #[cfg(feature = "jit-direct-only")]
+    { return false; }
+    #[cfg(not(feature = "jit-direct-only"))]
+    { return std::env::var("NYASH_USE_PLUGIN_BUILTINS").ok().as_deref() == Some("1"); }
 }
 
 /// Decide invocation policy for a known Box method.
diff --git a/src/jit/rt.rs b/src/jit/rt.rs
index dbc05b91..e39862a0 100644
--- a/src/jit/rt.rs
+++ b/src/jit/rt.rs
@@ -4,27 +4,21 @@ use crate::backend::vm::VMValue;
 use crate::jit::abi::JitValue;
 
 // Legacy TLS for hostcalls that still expect VMValue — keep for compatibility
-thread_local! {
-    static LEGACY_VM_ARGS: RefCell<Vec<VMValue>> = RefCell::new(Vec::new());
-}
+// Legacy VM args TLS — disabled in jit-direct-only (no-op/empty)
+#[cfg(not(feature = "jit-direct-only"))]
+thread_local! { static LEGACY_VM_ARGS: RefCell<Vec<VMValue>> = RefCell::new(Vec::new()); }
 
-pub fn set_legacy_vm_args(args: &[VMValue]) {
-    LEGACY_VM_ARGS.with(|cell| {
-        let mut v = cell.borrow_mut();
-        v.clear();
-        v.extend_from_slice(args);
-    });
-}
+#[cfg(not(feature = "jit-direct-only"))]
+pub fn set_legacy_vm_args(args: &[VMValue]) { LEGACY_VM_ARGS.with(|cell| { let mut v = cell.borrow_mut(); v.clear(); v.extend_from_slice(args); }); }
 
-pub fn with_legacy_vm_args<F, R>(f: F) -> R
-where
-    F: FnOnce(&[VMValue]) -> R,
-{
-    LEGACY_VM_ARGS.with(|cell| {
-        let v = cell.borrow();
-        f(&v)
-    })
-}
+#[cfg(feature = "jit-direct-only")]
+pub fn set_legacy_vm_args(_args: &[VMValue]) { /* no-op in jit-direct-only */ }
+
+#[cfg(not(feature = "jit-direct-only"))]
+pub fn with_legacy_vm_args<F, R>(f: F) -> R where F: FnOnce(&[VMValue]) -> R { LEGACY_VM_ARGS.with(|cell| { let v = cell.borrow(); f(&v) }) }
+
+#[cfg(feature = "jit-direct-only")]
+pub fn with_legacy_vm_args<F, R>(f: F) -> R where F: FnOnce(&[VMValue]) -> R { f(&[]) }
 
 // New TLS for independent JIT ABI values
 thread_local! {