diff --git a/crates/execution/assets/runners/wasm-runner.mjs b/crates/execution/assets/runners/wasm-runner.mjs
index 596567423..309bf7fcf 100644
--- a/crates/execution/assets/runners/wasm-runner.mjs
+++ b/crates/execution/assets/runners/wasm-runner.mjs
@@ -783,6 +783,7 @@ const stdioTtyCache = new Map();
 function stdioFdIsKernelTty(fd) {
   const descriptor = Number(fd) >>> 0;
   if (descriptor > 2) return false;
+  if (KERNEL_STDIO_SYNC_RPC) return true;
   if (stdioTtyCache.has(descriptor)) return stdioTtyCache.get(descriptor);
   let isTty = false;
   try {
@@ -4591,7 +4592,6 @@ wasiImport.fd_read = (fd, iovs, iovsLen, nreadPtr) => {
   const handle = __agentOSWasiMeasurePhase('fd_read', 'lookup_handle', () =>
     lookupFdHandle(numericFd)
   );
-
   if (handle?.kind === 'pipe-read') {
     try {
       const requestedLength = __agentOSWasiMeasurePhase('fd_read', 'iov_scan', () => {
@@ -5147,21 +5147,6 @@ wasiImport.fd_write = (fd, iovs, iovsLen, nwrittenPtr) => {
     }
   }
 
-  if (handle?.kind === 'passthrough') {
-    if (handle.readOnly === true) {
-      return WASI_ERRNO_ROFS;
-    }
-    return delegateManagedFdWrite
-      ? __agentOSWasiMeasurePhase('fd_write', 'delegate_call', () =>
-          delegateManagedFdWrite(handle.targetFd, iovs, iovsLen, nwrittenPtr)
-        )
-      : WASI_ERRNO_BADF;
-  }
-
-  if (!handle && numericFd <= 2) {
-    return WASI_ERRNO_BADF;
-  }
-
   if (numericFd === 1 || numericFd === 2) {
     try {
       const bytes = __agentOSWasiMeasurePhase('fd_write', 'guest_iov_collect', () =>
@@ -5189,6 +5174,21 @@ wasiImport.fd_write = (fd, iovs, iovsLen, nwrittenPtr) => {
     }
   }
 
+  if (handle?.kind === 'passthrough') {
+    if (handle.readOnly === true) {
+      return WASI_ERRNO_ROFS;
+    }
+    return delegateManagedFdWrite
+      ? __agentOSWasiMeasurePhase('fd_write', 'delegate_call', () =>
+          delegateManagedFdWrite(handle.targetFd, iovs, iovsLen, nwrittenPtr)
+        )
+      : WASI_ERRNO_BADF;
+  }
+
+  if (!handle && numericFd <= 2) {
+    return WASI_ERRNO_BADF;
+  }
+
   if (rejectClosedPassthroughFd(fd)) {
     return WASI_ERRNO_BADF;
   }
@@ -5562,7 +5562,8 @@ const hostTtyImport = {
   },
   // `host_tty.isatty(fd)` -> 1 if the guest fd is a kernel PTY, else 0.
   isatty(fd) {
-    return callSyncRpc('__kernel_isatty', [fd >>> 0]) === true ? 1 : 0;
+    const descriptor = Number(fd) >>> 0;
+    return descriptor <= 2 && stdioFdIsKernelTty(descriptor) ? 1 : 0;
   },
   // `host_tty.get_size(fd, colsPtr, rowsPtr)` -> writes the PTY window size as two
   // little-endian u16s and returns 0; non-zero (ENOTTY) if fd is not a PTY.
diff --git a/registry/native/c/Makefile b/registry/native/c/Makefile
index 66a065250..1e7bcc254 100644
--- a/registry/native/c/Makefile
+++ b/registry/native/c/Makefile
@@ -673,7 +673,7 @@ $(VIM_WCC): $(WASI_SDK_DIR)/bin/clang
 $(BUILD_DIR)/vim: fetch-vim $(VIM_BRIDGE_BUILD)/libtermcap.a $(VIM_WCC) wasm-opt-check
 	cd $(VIM_SRC)/src && \
 	CC="$(abspath $(VIM_WCC))" \
-	LDFLAGS="-L$(abspath $(VIM_BRIDGE_BUILD))" \
+	LDFLAGS="$(abspath $(VIM_BRIDGE_BUILD)/termios_bridge.o) -L$(abspath $(VIM_BRIDGE_BUILD))" \
 	vim_cv_toupper_broken=no \
 	vim_cv_terminfo=no \
 	vim_cv_tgetent=zero \
diff --git a/registry/native/c/vim/termios_bridge.c b/registry/native/c/vim/termios_bridge.c
index d18e19f8f..987fa1a05 100644
--- a/registry/native/c/vim/termios_bridge.c
+++ b/registry/native/c/vim/termios_bridge.c
@@ -61,10 +61,18 @@ static void ensure_shadow(void) {
  * apps (vim) print "Output is not to a terminal" and refuse full-screen mode.
  * host_tty.isatty is the authoritative PTY check the kernel exposes (a strong
  * symbol overriding the weak libc alias). */
-int isatty(int fd) {
+static int bridge_isatty(int fd) {
 	return __host_tty_isatty((unsigned int)fd) ? 1 : 0;
 }
 
+int __isatty(int fd) {
+	return bridge_isatty(fd);
+}
+
+int isatty(int fd) {
+	return bridge_isatty(fd);
+}
+
 int tcgetattr(int fd, struct termios *t) {
 	(void)fd;
 	if (!t) { errno = EFAULT; return -1; }