diff --git a/devel/llvm-cheri/Makefile b/devel/llvm-cheri/Makefile
index 21ae56230362..733933c863e4 100644
--- a/devel/llvm-cheri/Makefile
+++ b/devel/llvm-cheri/Makefile
@@ -83,7 +83,7 @@ CLANG_PORTDOCS=		clang
 CLANG_USES=		perl5
 # scan-build does require, but users can install it manually.
 CLANG_USE=		PERL5=build
-DOCS_BUILD_DEPENDS=	${PYTHON_PKGNAMEPREFIX}sphinx>=0,1:textproc/py-sphinx@${PY_FLAVOR} \
+DOCS_BUILD_DEPENDS+=	${PYTHON_PKGNAMEPREFIX}sphinx>=0,1:textproc/py-sphinx@${PY_FLAVOR} \
 			${PYTHON_PKGNAMEPREFIX}recommonmark>=0.0.20180530:textproc/py-recommonmark@${PY_FLAVOR}
 DOCS_CMAKE_ON=		-DLLVM_ENABLE_SPHINX=ON \
 			-DSPHINX_EXECUTABLE=${LOCALBASE}/bin/sphinx-build-${PYTHON_VER} \
diff --git a/devel/llvm-cheriot/Makefile b/devel/llvm-cheriot/Makefile
index 0c0cb1cfa5ee..d22112cd23b5 100644
--- a/devel/llvm-cheriot/Makefile
+++ b/devel/llvm-cheriot/Makefile
@@ -16,6 +16,9 @@ OPTIONS_EXCLUDE=	XTOOLCHAIN STATIC_LIBS
 LLVM_TARGETS=          RISCV
 CMAKE_FLAGS+=	-DLLVM_DEFAULT_TARGET_TRIPLE=riscv32-unknown-unknown
 
+DOCS_BUILD_DEPENDS= \
+	${PYTHON_PKGNAMEPREFIX}myst-parser>0:textproc/py-myst-parser@${PY_FLAVOR}
+
 MASTERDIR=	${.CURDIR}/../llvm-cheri
 
 .include "${MASTERDIR}/Makefile"