diff --git a/CMakeLists.txt b/CMakeLists.txt
index df57b1e..4a05fc4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,6 +41,6 @@ xo_export_cmake_config(${PROJECT_NAME} ${PROJECT_VERSION} ${PROJECT_NAME}Targets
 # docs targets depend on other library/utest/exec targets above,
 # --> must come after them.
 #
-#add_subdirectory(docs)
+add_subdirectory(docs)
 
 # end CMakeLists.txt
diff --git a/cmake/xo_gcConfig.cmake.in b/cmake/xo_gcConfig.cmake.in
index aebd133..a7eea6c 100644
--- a/cmake/xo_gcConfig.cmake.in
+++ b/cmake/xo_gcConfig.cmake.in
@@ -3,6 +3,7 @@
 include(CMakeFindDependencyMacro)
 find_dependency(xo_alloc2)
 find_dependency(xo_facet)
+find_dependency(subsys)
 find_dependency(indentlog)
 
 include("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
diff --git a/docs/_static/README b/docs/_static/README
new file mode 100644
index 0000000..7297d04
--- /dev/null
+++ b/docs/_static/README
@@ -0,0 +1 @@
+add any static {.html, .js, ..} files for sphinx to pickup here
diff --git a/docs/_static/img/favicon.ico b/docs/_static/img/favicon.ico
new file mode 100644
index 0000000..4163dd6
Binary files /dev/null and b/docs/_static/img/favicon.ico differ
diff --git a/docs/conf.py b/docs/conf.py
new file mode 100644
index 0000000..3d57cb0
--- /dev/null
+++ b/docs/conf.py
@@ -0,0 +1,39 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# For the full list of built-in configuration values, see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Project information -----------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
+
+project = 'xo gc documentation'
+copyright = '2026, Roland Conybeare'
+author = 'Roland Conybeare'
+
+# -- General configuration ---------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
+
+#extensions = []
+extensions = [ "breathe",
+               "sphinx.ext.mathjax",     # inline math
+               "sphinx.ext.autodoc",     # generate info from docstrings
+               "sphinxcontrib.ditaa",    # diagrams-through-ascii-art
+               "sphinxcontrib.plantuml"  # text -> uml diagrams
+              ]
+
+# note: breathe requires doxygen xml output -> must have GENERATE_XML = YES in Doxyfile.in
+#       match project name in Doxyfile.in
+breathe_default_project = "xodoxxml"
+
+templates_path = ['_templates']
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+
+pygments_style = 'sphinx'
+
+# -- Options for HTML output -------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
+
+#html_theme = 'alabaster'
+html_theme = 'sphinx_rtd_theme'
+html_static_path = ['_static']
+html_favicon = '_static/img/favicon.ico'
diff --git a/src/gc/CMakeLists.txt b/src/gc/CMakeLists.txt
index 44cef92..985592b 100644
--- a/src/gc/CMakeLists.txt
+++ b/src/gc/CMakeLists.txt
@@ -21,4 +21,5 @@ xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 $
 # note: deps here must also appear in cmake/xo_alloc2Config.cmake.in
 xo_dependency(${SELF_LIB} xo_alloc2)
 xo_dependency(${SELF_LIB} xo_facet)
+xo_dependency(${SELF_LIB} subsys)
 xo_dependency(${SELF_LIB} indentlog)