diff --git a/.kiro/specs/xce-harness-component/design.md b/.kiro/specs/xce-harness-component/design.md
index 4aae4a2b..0cb147d6 100644
--- a/.kiro/specs/xce-harness-component/design.md
+++ b/.kiro/specs/xce-harness-component/design.md
@@ -276,7 +276,7 @@ sequenceDiagram
 
 **Responsibilities & Constraints**
 - `controller)` case (`xce-build.sh:292-299`) drops `controller/xce_test` from its compile target list.
-- New `harness)` case follows the identical three-part template already used by `scheduler)`/`worker)`: `setup_build`, an explicit `meson compile` target list (`harness/xce_test harness/harness_unit_test`), then a conditional `meson test --suite harness`.
+- New `harness)` case follows the identical three-part template already used by `scheduler)`/`worker)`: `setup_build`, an explicit `meson compile` target list (all 6 harness targets: `xce_test`, `harness_unit_test`, and the four standalone test binaries), then a conditional `meson test --suite harness`.
 - `all)` requires no code change — it already compiles with no explicit target list, so it picks up the new `subdir('harness')` automatically.
 
 **Dependencies**
diff --git a/.kiro/specs/xce-harness-component/tasks.md b/.kiro/specs/xce-harness-component/tasks.md
index 8b2eb661..d2c548a1 100644
--- a/.kiro/specs/xce-harness-component/tasks.md
+++ b/.kiro/specs/xce-harness-component/tasks.md
@@ -33,7 +33,7 @@
   - _Requirements: 1.4, 3.1, 3.2, 3.4_
 
 - [ ] 3. Integration: decouple build orchestration, downstream workflows, and documentation
-- [ ] 3.1 Add the harness build entry and decouple it from the controller build
+- [x] 3.1 Add the harness build entry and decouple it from the controller build
   - In `src/tools/xce-build.sh`, drop `controller/xce_test` from the `controller)` case's compile target list; add a new `harness)` case following the identical three-part `setup_build` / `meson compile` / conditional `meson test --suite harness` template already used by `scheduler)`/`worker)`
   - Observable: `/xce-build harness` on a fresh build dir (no prior controller build) produces the `xce_test` binary and runs the `harness` suite; `/xce-build controller` alone does not produce `xce_test`
   - _Requirements: 2.1, 2.2, 2.3, 2.4_
diff --git a/src/tools/xce-build.sh b/src/tools/xce-build.sh
index b2fe1845..d929d1e5 100755
--- a/src/tools/xce-build.sh
+++ b/src/tools/xce-build.sh
@@ -221,7 +221,7 @@ MESON_OPTS+=(-Dcommit_id="$commit_id" -Dbuild_time="$build_time" -Ddirty_fingerp
 
 usage() {
     echo "Usage: $0 [component] [profile|build_dir] [build_dir] [--incremental] [--jobs N]"
-    echo "Components: all (default), lib, controller, scheduler, worker, apiserver, xcecli, xceadmin"
+    echo "Components: all (default), lib, controller, harness, scheduler, worker, apiserver, xcecli, xceadmin"
     echo "Profiles:   asan (default), debug (non-ASAN -O0 -g3, for gdb/cores), release"
     echo "--incremental: reconfigure the existing build dir in place instead of a full"
     echo "  rm -rf + fresh setup -- preserves other already-built components in the same"
@@ -292,12 +292,21 @@ case "$COMPONENT" in
     controller)
         setup_build
         echo "=== Building lib + controller + tests ==="
-        meson compile -C "$BUILD_DIR" "${MESON_COMPILE_JOB_OPTS[@]}" xce_controller controller_unit_test controller/xce_test
+        meson compile -C "$BUILD_DIR" "${MESON_COMPILE_JOB_OPTS[@]}" xce_controller controller_unit_test
         if [ "$RUN_TESTS" = 1 ]; then
             echo "=== Running controller tests ==="
             meson test -C "$BUILD_DIR" "${MESON_TEST_JOB_OPTS[@]}" --suite controller --print-errorlogs
         fi
         ;;
+    harness)
+        setup_build
+        echo "=== Building lib + harness + tests ==="
+        meson compile -C "$BUILD_DIR" "${MESON_COMPILE_JOB_OPTS[@]}" xce_test harness_unit_test resval_typeresolve_unit_test joblist_display_unit_test join_worker_args_unit_test listrow_json_unit_test
+        if [ "$RUN_TESTS" = 1 ]; then
+            echo "=== Running harness tests ==="
+            meson test -C "$BUILD_DIR" "${MESON_TEST_JOB_OPTS[@]}" --suite harness --print-errorlogs
+        fi
+        ;;
     scheduler)
         setup_build
         echo "=== Building lib + scheduler + tests ==="