diff --git a/tools/build.py b/tools/build.py
index 66f94fe0b0..7915ed03a4 100644
--- a/tools/build.py
+++ b/tools/build.py
@@ -214,11 +214,10 @@ if __name__ == '__main__':
     if options.cppcheck_validation:
         for toolchain in toolchains:
             if not TOOLCHAIN_CLASSES[toolchain].check_executable():
-                if TOOLCHAIN_PATHS[toolchain] == '':
-                    TOOLCHAIN_PATHS[toolchain] = "No path set"
+                search_path = TOOLCHAIN_PATHS[toolchain] or "No path set"
                 args_error(parser, "Could not find executable for %s.\n"
                                    "Currently set search path: %s"
-                           % (toolchain, TOOLCHAIN_PATHS[toolchain]))
+                           % (toolchain, search_path))
             for target in targets:
                 try:
                     mcu = TARGET_MAP[target]
diff --git a/tools/make.py b/tools/make.py
index 556b914487..e8d5a06d8b 100644
--- a/tools/make.py
+++ b/tools/make.py
@@ -233,11 +233,10 @@ if __name__ == '__main__':
         notify = None
 
     if not TOOLCHAIN_CLASSES[toolchain].check_executable():
-        if TOOLCHAIN_PATHS[toolchain] == '':
-            TOOLCHAIN_PATHS[toolchain] = "No path set"
+        search_path = TOOLCHAIN_PATHS[toolchain] or "No path set"
         args_error(parser, "Could not find executable for %s.\n"
                            "Currently set search path: %s"
-                           %(toolchain,TOOLCHAIN_PATHS[toolchain]))
+                           %(toolchain,search_path))
 
     # Test
     for test_no in p:
diff --git a/tools/test.py b/tools/test.py
index 491139d35b..5b8f9d97a3 100644
--- a/tools/test.py
+++ b/tools/test.py
@@ -116,11 +116,10 @@ if __name__ == '__main__':
         toolchain = options.tool[0]
 
         if not TOOLCHAIN_CLASSES[toolchain].check_executable():
-            if TOOLCHAIN_PATHS[toolchain] == '':
-                TOOLCHAIN_PATHS[toolchain] = "No path set"
+            search_path = TOOLCHAIN_PATHS[toolchain] or "No path set"
             args_error(parser, "Could not find executable for %s.\n"
                                "Currently set search path: %s"
-                       % (toolchain, TOOLCHAIN_PATHS[toolchain]))
+                       % (toolchain, search_path))
 
         # Find all tests in the relevant paths
         for path in all_paths:
diff --git a/tools/toolchains/arm.py b/tools/toolchains/arm.py
index 407d5374d5..26f6441833 100644
--- a/tools/toolchains/arm.py
+++ b/tools/toolchains/arm.py
@@ -44,6 +44,9 @@ class ARM(mbedToolchain):
 
     @staticmethod
     def check_executable():
+        """Returns True if the executable (armcc) location specified by the
+         user exists OR the executable can be found on the PATH.
+         Returns False otherwise."""
         if not TOOLCHAIN_PATHS["ARM"] or not exists(TOOLCHAIN_PATHS['ARM']):
             exe = find_executable('armcc')
             if not exe:
diff --git a/tools/toolchains/gcc.py b/tools/toolchains/gcc.py
index c66b7c45c7..fc54c25dae 100644
--- a/tools/toolchains/gcc.py
+++ b/tools/toolchains/gcc.py
@@ -272,6 +272,9 @@ class GCC(mbedToolchain):
 class GCC_ARM(GCC):
     @staticmethod
     def check_executable():
+        """Returns True if the executable (arm-none-eabi-gcc) location
+        specified by the user exists OR the executable can be found on the PATH.
+        Returns False otherwise."""
         if not TOOLCHAIN_PATHS["GCC_ARM"] or not exists(TOOLCHAIN_PATHS['GCC_ARM']):
             exe = find_executable('arm-none-eabi-gcc')
             if not exe:
@@ -306,6 +309,9 @@ class GCC_ARM(GCC):
 class GCC_CR(GCC):
     @staticmethod
     def check_executable():
+        """Returns True if the executable (arm-none-eabi-gcc) location
+        specified by the user exists OR the executable can be found on the PATH.
+        Returns False otherwise."""
         if not TOOLCHAIN_PATHS["GCC_CR"] or not exists(TOOLCHAIN_PATHS['GCC_CR']):
             exe = find_executable('arm-none-eabi-gcc')
             if not exe:
diff --git a/tools/toolchains/iar.py b/tools/toolchains/iar.py
index fc7047b080..01ac99846d 100644
--- a/tools/toolchains/iar.py
+++ b/tools/toolchains/iar.py
@@ -47,6 +47,9 @@ class IAR(mbedToolchain):
 
     @staticmethod
     def check_executable():
+        """Returns True if the executable (arm-none-eabi-gcc) location
+        specified by the user exists OR the executable can be found on the PATH.
+        Returns False otherwise."""
         if not TOOLCHAIN_PATHS["IAR"] or not exists(TOOLCHAIN_PATHS['IAR']):
             exe = find_executable('iccarm')
             if not exe: