diff --git a/Makefile.pre.in b/Makefile.pre.in
index f3086ec1462b6b..bf9143b9464b0d 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -2373,8 +2373,10 @@ multissltest: all
 # prevent race conditions with PGO builds. PGO builds use recursive make,
 # which can lead to two parallel `./python setup.py build` processes that
 # step on each others toes.
+# Only the main install gets a build-details.json.
 .PHONY: install
 install: @FRAMEWORKINSTALLFIRST@ @INSTALLTARGETS@ @FRAMEWORKINSTALLLAST@
+	$(INSTALL_DATA) `cat pybuilddir.txt`/build-details.json $(DESTDIR)$(LIBDEST); \
 	if test "x$(ENSUREPIP)" != "xno"  ; then \
 		case $(ENSUREPIP) in \
 			upgrade) ensurepip="--upgrade" ;; \
@@ -2827,7 +2829,6 @@ libinstall:	all $(srcdir)/Modules/xxmodule.c
 	done
 	$(INSTALL_DATA) `cat pybuilddir.txt`/_sysconfigdata_$(ABIFLAGS)_$(MACHDEP)_$(MULTIARCH).py $(DESTDIR)$(LIBDEST); \
 	$(INSTALL_DATA) `cat pybuilddir.txt`/_sysconfig_vars_$(ABIFLAGS)_$(MACHDEP)_$(MULTIARCH).json $(DESTDIR)$(LIBDEST); \
-	$(INSTALL_DATA) `cat pybuilddir.txt`/build-details.json $(DESTDIR)$(LIBDEST); \
 	$(INSTALL_DATA) `cat pybuilddir.txt`/_missing_stdlib_info.py $(DESTDIR)$(LIBDEST); \
 	$(INSTALL_DATA) $(srcdir)/LICENSE $(DESTDIR)$(LIBDEST)/LICENSE.txt
 	@ # If app store compliance has been configured, apply the patch to the
diff --git a/Misc/NEWS.d/next/Build/2025-12-04-20-57-15.gh-issue-131372.o397g7.rst b/Misc/NEWS.d/next/Build/2025-12-04-20-57-15.gh-issue-131372.o397g7.rst
new file mode 100644
index 00000000000000..362197f110b7dd
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2025-12-04-20-57-15.gh-issue-131372.o397g7.rst
@@ -0,0 +1,2 @@
+``build-details.py`` will only be installed as part of the main install
+(``make install``). ``make altinstall`` will no longer include it.