diff --git a/cli/CMakeLists.txt b/cli/CMakeLists.txt
index ce26788d0..91aa5ee2c 100644
--- a/cli/CMakeLists.txt
+++ b/cli/CMakeLists.txt
@@ -36,7 +36,9 @@ add_dependencies(zli
     commands
     utils
     logger
-    xgboost_external
 )
+if(TARGET xgboost_external)
+    add_dependencies(zli xgboost_external)
+endif()
 
 apply_openzl_compile_options_to_target(zli)
diff --git a/custom_parsers/CMakeLists.txt b/custom_parsers/CMakeLists.txt
index aa35fdc40..b7b7db7d5 100644
--- a/custom_parsers/CMakeLists.txt
+++ b/custom_parsers/CMakeLists.txt
@@ -48,7 +48,10 @@ target_link_libraries(custom_parsers
     parquet_graph
     shared_components
 )
-add_dependencies(custom_parsers openzl openzl_cpp xgboost_external)
+add_dependencies(custom_parsers openzl openzl_cpp)
+if(TARGET xgboost_external)
+    add_dependencies(custom_parsers xgboost_external)
+endif()
 apply_openzl_compile_options_to_target(custom_parsers
     csv_parser
     parquet_graph
diff --git a/tools/ml_selector/CMakeLists.txt b/tools/ml_selector/CMakeLists.txt
index e6b1d3152..c46c0f81a 100644
--- a/tools/ml_selector/CMakeLists.txt
+++ b/tools/ml_selector/CMakeLists.txt
@@ -1,92 +1,110 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 if(OPENZL_BUILD_ML_SELECTOR)
-    include(ExternalProject)
-    include(GNUInstallDirs)
-
-    # Build xgboost as an external project
-    set(XGBOOST_INSTALL_DIR "${CMAKE_CURRENT_BINARY_DIR}/xgboost-install")
-    set(XGBOOST_LIB_DIR "${XGBOOST_INSTALL_DIR}/lib")
+    # Prefer a pre-installed xgboost (e.g. from conda/pixi) when one is
+    # available, and only fall back to building it from source otherwise. The
+    # CONDA_PREFIX hint lets `pixi run` environments be discovered without any
+    # extra -DCMAKE_PREFIX_PATH flag.
+    find_package(xgboost CONFIG QUIET HINTS "$ENV{CONDA_PREFIX}")
+
+    if(xgboost_FOUND)
+        message(STATUS "Using pre-installed xgboost: ${xgboost_DIR}")
+        # The imported xgboost::xgboost target carries its own include dirs
+        # (covering both xgboost/ and dmlc/ headers) and statically bundles dmlc,
+        # so no separate dmlc link target or include path is required.
+        set(OPENZL_XGBOOST_LIBS xgboost::xgboost)
+    else()
+        message(STATUS
+            "Pre-installed xgboost not found; building from source via ExternalProject")
+        include(ExternalProject)
+        include(GNUInstallDirs)
+
+        # Build xgboost as an external project
+        set(XGBOOST_INSTALL_DIR "${CMAKE_CURRENT_BINARY_DIR}/xgboost-install")
+        set(XGBOOST_LIB_DIR "${XGBOOST_INSTALL_DIR}/lib")
+
+        # Create install directories at configure time
+        file(MAKE_DIRECTORY ${XGBOOST_INSTALL_DIR}/include)
+        file(MAKE_DIRECTORY ${XGBOOST_LIB_DIR})
+
+        # On Windows/MSVC, static libraries don't have a "lib" prefix
+        if(MSVC)
+            set(XGBOOST_LIB_NAME "xgboost${CMAKE_STATIC_LIBRARY_SUFFIX}")
+            set(DMLC_LIB_NAME "dmlc${CMAKE_STATIC_LIBRARY_SUFFIX}")
+        else()
+            set(XGBOOST_LIB_NAME "libxgboost${CMAKE_STATIC_LIBRARY_SUFFIX}")
+            set(DMLC_LIB_NAME "libdmlc${CMAKE_STATIC_LIBRARY_SUFFIX}")
+        endif()
 
-    # Create install directories at configure time
-    file(MAKE_DIRECTORY ${XGBOOST_INSTALL_DIR}/include)
-    file(MAKE_DIRECTORY ${XGBOOST_LIB_DIR})
+        # Enable C++ exceptions for ClangCL.
+        if(MSVC)
+            set(XGBOOST_CXX_FLAGS
+                "-DDMLC_LOG_STACK_TRACE=0 /EHsc")
+        else()
+            set(XGBOOST_CXX_FLAGS
+                "-DDMLC_LOG_STACK_TRACE=0")
+        endif()
 
-    # On Windows/MSVC, static libraries don't have a "lib" prefix
-    if(MSVC)
-        set(XGBOOST_LIB_NAME "xgboost${CMAKE_STATIC_LIBRARY_SUFFIX}")
-        set(DMLC_LIB_NAME "dmlc${CMAKE_STATIC_LIBRARY_SUFFIX}")
-    else()
-        set(XGBOOST_LIB_NAME "libxgboost${CMAKE_STATIC_LIBRARY_SUFFIX}")
-        set(DMLC_LIB_NAME "libdmlc${CMAKE_STATIC_LIBRARY_SUFFIX}")
-    endif()
+        # Add XGBoost as external project
+        # Disable DMLC stack trace to avoid execinfo.h
+        ExternalProject_Add(xgboost_external
+            GIT_REPOSITORY https://github.com/dmlc/xgboost.git
+            GIT_TAG        ccb511768e13d1670c10be07dea89d0edca138f3 # v3.1.0
+            GIT_SUBMODULES "dmlc-core"
+            GIT_SHALLOW    TRUE
+            CMAKE_ARGS
+                -DCMAKE_INSTALL_PREFIX=${XGBOOST_INSTALL_DIR}
+                -DCMAKE_INSTALL_LIBDIR=lib
+                -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+                -DUSE_OPENMP=OFF
+                -DUSE_CUDA=OFF
+                -DUSE_NCCL=OFF
+                -DCMAKE_POSITION_INDEPENDENT_CODE=ON
+                -DBUILD_STATIC_LIB=ON
+                ${XGBOOST_EXTRA_CMAKE_ARGS}
+            CMAKE_CACHE_ARGS
+                "-DCMAKE_C_FLAGS:STRING=-DDMLC_LOG_STACK_TRACE=0"
+                "-DCMAKE_CXX_FLAGS:STRING=${XGBOOST_CXX_FLAGS}"
+                "-DBUILD_TESTING:BOOL=OFF"
+                "-DCMAKE_POLICY_DEFAULT_CMP0091:STRING=NEW"
+                "-DCMAKE_MSVC_RUNTIME_LIBRARY:STRING=${CMAKE_MSVC_RUNTIME_LIBRARY}"
+            BUILD_BYPRODUCTS
+                ${XGBOOST_LIB_DIR}/${XGBOOST_LIB_NAME}
+                ${XGBOOST_LIB_DIR}/${DMLC_LIB_NAME}
+            LOG_DOWNLOAD ON
+            LOG_CONFIGURE ON
+            LOG_BUILD ON
+            LOG_INSTALL ON
+        )
 
-    # Enable C++ exceptions for ClangCL.
-    if(MSVC)
-        set(XGBOOST_CXX_FLAGS
-            "-DDMLC_LOG_STACK_TRACE=0 /EHsc")
-    else()
-        set(XGBOOST_CXX_FLAGS
-            "-DDMLC_LOG_STACK_TRACE=0")
-    endif()
+        # Create imported targets
+        add_library(xgboost STATIC IMPORTED GLOBAL)
+        set_target_properties(xgboost PROPERTIES
+            IMPORTED_LOCATION
+                ${XGBOOST_LIB_DIR}/${XGBOOST_LIB_NAME}
+            INTERFACE_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
+            INTERFACE_SYSTEM_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
+            INTERFACE_COMPILE_DEFINITIONS "DMLC_LOG_STACK_TRACE=0"
+        )
+        add_dependencies(xgboost xgboost_external)
 
-    # Add XGBoost as external project
-    # Disable DMLC stack trace to avoid execinfo.h
-    ExternalProject_Add(xgboost_external
-        GIT_REPOSITORY https://github.com/dmlc/xgboost.git
-        GIT_TAG        ccb511768e13d1670c10be07dea89d0edca138f3 # v3.1.0
-        GIT_SUBMODULES "dmlc-core"
-        GIT_SHALLOW    TRUE
-        CMAKE_ARGS
-            -DCMAKE_INSTALL_PREFIX=${XGBOOST_INSTALL_DIR}
-            -DCMAKE_INSTALL_LIBDIR=lib
-            -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
-            -DUSE_OPENMP=OFF
-            -DUSE_CUDA=OFF
-            -DUSE_NCCL=OFF
-            -DCMAKE_POSITION_INDEPENDENT_CODE=ON
-            -DBUILD_STATIC_LIB=ON
-            ${XGBOOST_EXTRA_CMAKE_ARGS}
-        CMAKE_CACHE_ARGS
-            "-DCMAKE_C_FLAGS:STRING=-DDMLC_LOG_STACK_TRACE=0"
-            "-DCMAKE_CXX_FLAGS:STRING=${XGBOOST_CXX_FLAGS}"
-            "-DBUILD_TESTING:BOOL=OFF"
-            "-DCMAKE_POLICY_DEFAULT_CMP0091:STRING=NEW"
-            "-DCMAKE_MSVC_RUNTIME_LIBRARY:STRING=${CMAKE_MSVC_RUNTIME_LIBRARY}"
-        BUILD_BYPRODUCTS
-            ${XGBOOST_LIB_DIR}/${XGBOOST_LIB_NAME}
-            ${XGBOOST_LIB_DIR}/${DMLC_LIB_NAME}
-        LOG_DOWNLOAD ON
-        LOG_CONFIGURE ON
-        LOG_BUILD ON
-        LOG_INSTALL ON
-    )
+        if(WIN32 OR MINGW)
+            set_target_properties(xgboost PROPERTIES
+                INTERFACE_LINK_LIBRARIES "ws2_32")
+        endif()
 
-    # Create imported targets
-    add_library(xgboost STATIC IMPORTED GLOBAL)
-    set_target_properties(xgboost PROPERTIES
-        IMPORTED_LOCATION
-            ${XGBOOST_LIB_DIR}/${XGBOOST_LIB_NAME}
-        INTERFACE_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
-        INTERFACE_SYSTEM_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
-        INTERFACE_COMPILE_DEFINITIONS "DMLC_LOG_STACK_TRACE=0"
-    )
-    add_dependencies(xgboost xgboost_external)
+        add_library(dmlc STATIC IMPORTED GLOBAL)
+        set_target_properties(dmlc PROPERTIES
+            IMPORTED_LOCATION
+                ${XGBOOST_LIB_DIR}/${DMLC_LIB_NAME}
+            INTERFACE_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
+            INTERFACE_SYSTEM_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
+            INTERFACE_COMPILE_DEFINITIONS "DMLC_LOG_STACK_TRACE=0"
+        )
+        add_dependencies(dmlc xgboost_external)
 
-    if(WIN32 OR MINGW)
-        set_target_properties(xgboost PROPERTIES
-            INTERFACE_LINK_LIBRARIES "ws2_32")
+        set(OPENZL_XGBOOST_LIBS xgboost dmlc)
     endif()
 
-    add_library(dmlc STATIC IMPORTED GLOBAL)
-    set_target_properties(dmlc PROPERTIES
-        IMPORTED_LOCATION
-            ${XGBOOST_LIB_DIR}/${DMLC_LIB_NAME}
-        INTERFACE_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
-        INTERFACE_SYSTEM_INCLUDE_DIRECTORIES ${XGBOOST_INSTALL_DIR}/include
-        INTERFACE_COMPILE_DEFINITIONS "DMLC_LOG_STACK_TRACE=0"
-    )
-    add_dependencies(dmlc xgboost_external)
-
     add_library(ml_selector
         ml_selector_trainer.cpp
         ml_selector_trainer.h
@@ -94,10 +112,6 @@ if(OPENZL_BUILD_ML_SELECTOR)
         ml_features.h
     )
 
-    target_include_directories(ml_selector
-        SYSTEM PUBLIC
-            ${XGBOOST_INSTALL_DIR}/include
-    )
     target_include_directories(ml_selector
         PUBLIC
             ${PROJECT_SOURCE_DIR}
@@ -113,15 +127,18 @@ if(OPENZL_BUILD_ML_SELECTOR)
             PUBLIC
             openzl
             openzl_cpp
-            xgboost
-            dmlc
+            ${OPENZL_XGBOOST_LIBS}
         )
 
-    add_dependencies(ml_selector xgboost_external)
+    if(TARGET xgboost_external)
+        add_dependencies(ml_selector xgboost_external)
+    endif()
 
     if (OPENZL_BUILD_TESTS)
         add_executable(test_ml_selector tests/test_mlSelectorGraph.cpp)
-        add_dependencies(test_ml_selector xgboost_external)
+        if(TARGET xgboost_external)
+            add_dependencies(test_ml_selector xgboost_external)
+        endif()
 
         target_link_libraries(test_ml_selector
             PRIVATE
@@ -139,7 +156,9 @@ if(OPENZL_BUILD_ML_SELECTOR)
         if (OPENZL_ALLOW_INTROSPECTION)
             add_executable(test_ml_selector_trainer
                 tests/test_mlSelectorTrainer.cpp)
-            add_dependencies(test_ml_selector_trainer xgboost_external)
+            if(TARGET xgboost_external)
+                add_dependencies(test_ml_selector_trainer xgboost_external)
+            endif()
 
             target_link_libraries(test_ml_selector_trainer
                 PRIVATE
diff --git a/tools/parquet/CMakeLists.txt b/tools/parquet/CMakeLists.txt
index 68675ef54..20af4e17b 100644
--- a/tools/parquet/CMakeLists.txt
+++ b/tools/parquet/CMakeLists.txt
@@ -1,80 +1,99 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 
 if (OPENZL_BUILD_PARQUET_TOOLS)
-  set(ARROW_PREFIX "${CMAKE_CURRENT_BINARY_DIR}/arrow_ep")
+  # Prefer a pre-installed Arrow/Parquet (e.g. from conda/pixi) when available,
+  # and only fall back to building it from source otherwise. The CONDA_PREFIX
+  # hint lets `pixi run` environments be discovered without an extra
+  # -DCMAKE_PREFIX_PATH flag.
+  find_package(Arrow CONFIG QUIET HINTS "$ENV{CONDA_PREFIX}")
+  find_package(Parquet CONFIG QUIET HINTS "$ENV{CONDA_PREFIX}")
 
-  # Point arrow to the zstd build directory
-  list(APPEND CMAKE_PREFIX_PATH "${zstd_BINARY_DIR}")
+  if(Arrow_FOUND AND Parquet_FOUND)
+    message(STATUS "Using pre-installed Arrow/Parquet: ${Arrow_DIR}")
+    # Parquet::parquet_shared transitively links Arrow::arrow_shared and carries
+    # its own include dirs; no ExternalProject or imported targets are required.
+    set(OPENZL_PARQUET_LIBS Parquet::parquet_shared Arrow::arrow_shared)
+  else()
+    message(STATUS
+        "Pre-installed Arrow/Parquet not found; building from source via ExternalProject")
+    set(ARROW_PREFIX "${CMAKE_CURRENT_BINARY_DIR}/arrow_ep")
 
-  set(ARROW_CMAKE_ARGS
-      -DARROW_PARQUET=ON
-      -DARROW_DEPENDENCY_SOURCE=AUTO
-      -DARROW_WITH_THRIFT=ON
-      -DARROW_WITH_LZ4=OFF # fix
-      -DARROW_WITH_SNAPPY=ON
-      -DARROW_WITH_ZLIB=ON
-      -DARROW_WITH_ZSTD=ON
-      -DARROW_MIMALLOC=OFF
-      -DCMAKE_INSTALL_PREFIX=${ARROW_PREFIX}/install
-      -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
-      -DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH}
-      -DCMAKE_POLICY_VERSION_MINIMUM=3.5
-      -DARROW_CXXFLAGS=-Wno-documentation)
-  set(ARROW_LIBDIR ${ARROW_PREFIX}/install/${CMAKE_INSTALL_LIBDIR})
+    # Point arrow to the zstd build directory
+    list(APPEND CMAKE_PREFIX_PATH "${zstd_BINARY_DIR}")
 
-  set(ARROW_DEPS thrift snappy)
-  set(thrift_ROOT ${ARROW_PREFIX}/src/arrow_ep-build/thrift_ep-install)
-  set(snappy_ROOT ${ARROW_PREFIX}/src/arrow_ep-build/snappy_ep/src/snappy_ep-install)
+    set(ARROW_CMAKE_ARGS
+        -DARROW_PARQUET=ON
+        -DARROW_DEPENDENCY_SOURCE=AUTO
+        -DARROW_WITH_THRIFT=ON
+        -DARROW_WITH_LZ4=OFF # fix
+        -DARROW_WITH_SNAPPY=ON
+        -DARROW_WITH_ZLIB=ON
+        -DARROW_WITH_ZSTD=ON
+        -DARROW_MIMALLOC=OFF
+        -DCMAKE_INSTALL_PREFIX=${ARROW_PREFIX}/install
+        -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+        -DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH}
+        -DCMAKE_POLICY_VERSION_MINIMUM=3.5
+        -DARROW_CXXFLAGS=-Wno-documentation)
+    set(ARROW_LIBDIR ${ARROW_PREFIX}/install/${CMAKE_INSTALL_LIBDIR})
 
-  foreach (dep ${ARROW_DEPS})
-    add_library(${dep} STATIC IMPORTED GLOBAL)
-    set(${dep}_LIB ${${dep}_ROOT}/lib/lib${dep}.a)
-    list(APPEND ARROW_DEPS_LIBS ${${dep}_LIB})
-    file(MAKE_DIRECTORY ${${dep}_ROOT}/include)
-    set(${dep}_INCLUDE_DIR ${${dep}_ROOT}/include)
-    set_property(TARGET ${dep} PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${${dep}_INCLUDE_DIR})
-    set_property(TARGET ${dep} PROPERTY IMPORTED_LOCATION ${${dep}_LIB})
-  endforeach()
+    set(ARROW_DEPS thrift snappy)
+    set(thrift_ROOT ${ARROW_PREFIX}/src/arrow_ep-build/thrift_ep-install)
+    set(snappy_ROOT ${ARROW_PREFIX}/src/arrow_ep-build/snappy_ep/src/snappy_ep-install)
 
-  set(ZL_ARROW_BUILD_VERSION 20.0.0)
-  set(ZL_ARROW_BUILD_SHA256_CHECKSUM 67e31a4f46528634b8c3cbb0dc60ac8f85859d906b400d83d0b6f732b0c5b0e3)
-  set(ZL_ARROW_SOURCE_URL
-      "https://github.com/apache/arrow/archive/refs/tags/apache-arrow-${ZL_ARROW_BUILD_VERSION}.tar.gz"
-  )
-  include(ExternalProject)
-  ExternalProject_Add(
-      arrow_ep
-      PREFIX ${ARROW_PREFIX}
-      URL ${ZL_ARROW_SOURCE_URL}
-      URL_HASH SHA256=${ZL_ARROW_BUILD_SHA256_CHECKSUM}
-      SOURCE_SUBDIR cpp
-      CMAKE_ARGS ${ARROW_CMAKE_ARGS}
-      BUILD_BYPRODUCTS ${ARROW_LIBDIR}/libarrow.a
-                       ${ARROW_LIBDIR}/libparquet.a
-                       ${ARROW_DEPS_LIBS}
-  )
+    foreach (dep ${ARROW_DEPS})
+      add_library(${dep} STATIC IMPORTED GLOBAL)
+      set(${dep}_LIB ${${dep}_ROOT}/lib/lib${dep}.a)
+      list(APPEND ARROW_DEPS_LIBS ${${dep}_LIB})
+      file(MAKE_DIRECTORY ${${dep}_ROOT}/include)
+      set(${dep}_INCLUDE_DIR ${${dep}_ROOT}/include)
+      set_property(TARGET ${dep} PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${${dep}_INCLUDE_DIR})
+      set_property(TARGET ${dep} PROPERTY IMPORTED_LOCATION ${${dep}_LIB})
+    endforeach()
 
-  add_library(arrow STATIC IMPORTED GLOBAL)
-  add_library(parquet STATIC IMPORTED GLOBAL)
-  add_dependencies(arrow arrow_ep)
-  add_dependencies(parquet arrow)
+    set(ZL_ARROW_BUILD_VERSION 20.0.0)
+    set(ZL_ARROW_BUILD_SHA256_CHECKSUM 67e31a4f46528634b8c3cbb0dc60ac8f85859d906b400d83d0b6f732b0c5b0e3)
+    set(ZL_ARROW_SOURCE_URL
+        "https://github.com/apache/arrow/archive/refs/tags/apache-arrow-${ZL_ARROW_BUILD_VERSION}.tar.gz"
+    )
+    include(ExternalProject)
+    ExternalProject_Add(
+        arrow_ep
+        PREFIX ${ARROW_PREFIX}
+        URL ${ZL_ARROW_SOURCE_URL}
+        URL_HASH SHA256=${ZL_ARROW_BUILD_SHA256_CHECKSUM}
+        SOURCE_SUBDIR cpp
+        CMAKE_ARGS ${ARROW_CMAKE_ARGS}
+        BUILD_BYPRODUCTS ${ARROW_LIBDIR}/libarrow.a
+                         ${ARROW_LIBDIR}/libparquet.a
+                         ${ARROW_DEPS_LIBS}
+    )
 
-  file(MAKE_DIRECTORY ${ARROW_PREFIX}/install/include)
-  set_target_properties(
-      arrow parquet PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
-                                  ${ARROW_PREFIX}/install/include)
-  set_target_properties(arrow PROPERTIES IMPORTED_LOCATION
-                                          ${ARROW_LIBDIR}/libarrow.a)
-  set_target_properties(parquet PROPERTIES IMPORTED_LOCATION
-                                          ${ARROW_LIBDIR}/libparquet.a)
+    add_library(arrow STATIC IMPORTED GLOBAL)
+    add_library(parquet STATIC IMPORTED GLOBAL)
+    add_dependencies(arrow arrow_ep)
+    add_dependencies(parquet arrow)
 
-    set_property(
-      TARGET
-      arrow
-      PROPERTY
-      INTERFACE_LINK_LIBRARIES
-        libzstd z ${ARROW_DEPS})
-  set_property(TARGET parquet PROPERTY INTERFACE_LINK_LIBRARIES arrow)
+    file(MAKE_DIRECTORY ${ARROW_PREFIX}/install/include)
+    set_target_properties(
+        arrow parquet PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
+                                    ${ARROW_PREFIX}/install/include)
+    set_target_properties(arrow PROPERTIES IMPORTED_LOCATION
+                                            ${ARROW_LIBDIR}/libarrow.a)
+    set_target_properties(parquet PROPERTIES IMPORTED_LOCATION
+                                            ${ARROW_LIBDIR}/libparquet.a)
+
+      set_property(
+        TARGET
+        arrow
+        PROPERTY
+        INTERFACE_LINK_LIBRARIES
+          libzstd z ${ARROW_DEPS})
+    set_property(TARGET parquet PROPERTY INTERFACE_LINK_LIBRARIES arrow)
+
+    # The parquet target already pulls arrow transitively.
+    set(OPENZL_PARQUET_LIBS parquet)
+  endif()
 
   file(
       GLOB_RECURSE make_canonical_parquet_sources
@@ -84,8 +103,11 @@ if (OPENZL_BUILD_PARQUET_TOOLS)
 
   target_link_libraries(
       make_canonical_parquet
-      PRIVATE arg openzl parquet tools_io)
-  add_dependencies(make_canonical_parquet arg openzl parquet tools_io)
+      PRIVATE arg openzl ${OPENZL_PARQUET_LIBS} tools_io)
+  add_dependencies(make_canonical_parquet arg openzl tools_io)
+  if(TARGET arrow_ep)
+    add_dependencies(make_canonical_parquet arrow_ep)
+  endif()
 
   apply_openzl_compile_options_to_target(make_canonical_parquet)
 endif()
diff --git a/tools/training/CMakeLists.txt b/tools/training/CMakeLists.txt
index c93b090ad..d6777316e 100644
--- a/tools/training/CMakeLists.txt
+++ b/tools/training/CMakeLists.txt
@@ -37,8 +37,10 @@ if (OPENZL_BUILD_TRAINING_TOOLS)
         openzl_cpp
         tools_io
         logger
-        ml_selector
-        xgboost_external)
+        ml_selector)
+    if(TARGET xgboost_external)
+        add_dependencies(tools_training xgboost_external)
+    endif()
 
   if (OPENZL_BUILD_TESTS AND OPENZL_ALLOW_INTROSPECTION)
     file(
@@ -52,7 +54,9 @@ if (OPENZL_BUILD_TRAINING_TOOLS)
         CONFIGURE_DEPENDS
         "${CMAKE_CURRENT_LIST_DIR}/tests/*.h")
     add_executable(test_training ${test_training_srcs} ${test_training_headers})
-    add_dependencies(test_training xgboost_external)
+    if(TARGET xgboost_external)
+        add_dependencies(test_training xgboost_external)
+    endif()
     target_link_libraries(
         test_training
         PRIVATE