diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -313,7 +313,7 @@
 if(LLVM_LIBC_FULL_BUILD)
   list(APPEND TARGET_LIBC_ENTRYPOINTS
     # assert.h entrypoints
-    # libc.src.assert.__assert_fail
+    libc.src.assert.__assert_fail
 
     # dirent.h entrypoints
     libc.src.dirent.closedir
diff --git a/libc/spec/llvm_libc_ext.td b/libc/spec/llvm_libc_ext.td
--- a/libc/spec/llvm_libc_ext.td
+++ b/libc/spec/llvm_libc_ext.td
@@ -28,7 +28,6 @@
               "__assert_fail",
               RetValSpec<NoReturn>,
               [ArgSpec<ConstCharPtr>, ArgSpec<ConstCharPtr>, ArgSpec<UnsignedType>, ArgSpec<ConstCharPtr>]
-
           >,
       ]
   >;
diff --git a/libc/src/CMakeLists.txt b/libc/src/CMakeLists.txt
--- a/libc/src/CMakeLists.txt
+++ b/libc/src/CMakeLists.txt
@@ -23,9 +23,7 @@
   return()
 endif()
 
-# The signal API is currently disabled as signal.h is incorrect.
-# since assert uses the signal API, we disable assert also.
-# add_subdirectory(assert)
+add_subdirectory(assert)
 add_subdirectory(setjmp)
 add_subdirectory(signal)
 add_subdirectory(spawn)
diff --git a/libc/test/src/CMakeLists.txt b/libc/test/src/CMakeLists.txt
--- a/libc/test/src/CMakeLists.txt
+++ b/libc/test/src/CMakeLists.txt
@@ -49,9 +49,7 @@
 endif()
 
 add_subdirectory(dirent)
-# The signal API is currently disabled as signal.h is incorrect.
-# since assert uses the signal API, we disable assert also.
-# add_subdirectory(assert)
+add_subdirectory(assert)
 add_subdirectory(setjmp)
 add_subdirectory(signal)
 add_subdirectory(spawn)