diff --git a/libc-bottom-half/headers/public/wasi/api.h b/libc-bottom-half/headers/public/wasi/api.h
index 45a6506e2..f2cfbe7a1 100644
--- a/libc-bottom-half/headers/public/wasi/api.h
+++ b/libc-bottom-half/headers/public/wasi/api.h
@@ -2099,12 +2099,14 @@ __wasi_errno_t __wasi_sock_shutdown(
  *
  * @see https://github.com/WebAssembly/wasi-threads/#readme
  */
-int32_t __wasi_thread_spawn(
+uint8_t __wasi_thread_spawn(
     /**
      * A pointer to an opaque struct to be passed to the module's entry
      * function.
      */
-    void *start_arg
+    void *start_arg,
+	uint8_t *error,
+	uint32_t *tid
 )  __attribute__((__warn_unused_result__));
 #endif
 
diff --git a/libc-bottom-half/sources/__wasilibc_real.c b/libc-bottom-half/sources/__wasilibc_real.c
index d2e6b71c6..6f8bbdadd 100644
--- a/libc-bottom-half/sources/__wasilibc_real.c
+++ b/libc-bottom-half/sources/__wasilibc_real.c
@@ -660,12 +660,25 @@ __wasi_errno_t __wasi_sock_shutdown(
 }
 
 #ifdef _REENTRANT
-int32_t __imported_wasi_thread_spawn(int32_t arg0) __attribute__((
+void __imported_wasi_thread_spawn(int32_t arg0, int32_t arg1) __attribute__((
     __import_module__("wasi"),
-    __import_name__("thread_spawn")
-));
-
-int32_t __wasi_thread_spawn(void* start_arg) {
-    return __imported_wasi_thread_spawn((int32_t) start_arg);
+    __import_name__("thread-spawn")
+));
+
+uint8_t __wasi_thread_spawn(void *start_arg, uint8_t *error, uint32_t *tid) {
+    struct {
+        uint8_t is_error;
+        union {
+            uint8_t error;
+            uint32_t tid;
+        } u;
+    } error_or_tid;
+    __imported_wasi_thread_spawn((int32_t) start_arg, (int32_t)(intptr_t) &error_or_tid);
+    if (error_or_tid.is_error) {
+        *error = error_or_tid.u.error;
+        return 1;
+    }
+    *tid = error_or_tid.u.tid;
+    return 0;
 }
 #endif
diff --git a/libc-top-half/musl/src/thread/pthread_create.c b/libc-top-half/musl/src/thread/pthread_create.c
index 676e2ccf9..a5bcd3fca 100644
--- a/libc-top-half/musl/src/thread/pthread_create.c
+++ b/libc-top-half/musl/src/thread/pthread_create.c
@@ -351,6 +351,9 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 	void* new_tls_base;
 	size_t tls_offset;
 	tls_size += tls_align;
+	uint8_t is_error;
+	uint32_t tid;
+	uint8_t error;
 #endif
 
 #ifdef __wasilibc_unmodified_upstream
@@ -516,7 +519,7 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 	 * of the current module and start executing the entry function. The
 	 * wasi-threads specification requires the module to export a
 	 * `wasi_thread_start` function, which is invoked with `args`. */
-	ret = __wasi_thread_spawn((void *) args);
+	is_error = __wasi_thread_spawn((void *) args, &error, &tid);
 #endif
 
 #ifdef __wasilibc_unmodified_upstream
@@ -542,10 +545,15 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 	 * did succeed, then we store the TID atomically, since this parent thread
 	 * is racing with the child thread to set this field; this way, whichever
 	 * thread reaches this point first can continue without waiting. */
-	if (ret < 0) {
+	if (is_error) {
+		/*
+		 * At this point EAGAIN is the only defined error in wasi-threads.
+		 * when the list grows, maybe we should convert errno.
+		 */
 		ret = -EAGAIN;
 	} else {
-		atomic_store((atomic_int *) &(new->tid), ret);
+		atomic_store((atomic_int *) &(new->tid), (int)tid);
+        ret = 0;
 	}
 #endif