diff --git a/exports/taskfiles/utils/cmake.yaml b/exports/taskfiles/utils/cmake.yaml
index f14699c..0b59009 100644
--- a/exports/taskfiles/utils/cmake.yaml
+++ b/exports/taskfiles/utils/cmake.yaml
@@ -15,7 +15,8 @@ tasks:
   # @param {string} BUILD_DIR Directory containing the generated build system to use.
   # @param {string[]} [EXTRA_ARGS] Any additional arguments to pass to the build command.
   # @param {int} [JOBS] The maximum number of concurrent processes to use when building. If
-  # omitted, the native build tool's default number is used. See `man cmake`.
+  # omitted, defaults to the number of logical CPUs reported by the system. Falls back to 1 for a
+  # serial build if the CPU count cannot be determined.
   # @param {string[]} [TARGETS] A list of specific targets to build instead of the default target.
   build:
     internal: true
@@ -23,8 +24,16 @@ tasks:
     vars:
       EXTRA_ARGS:
         ref: "default (list) .EXTRA_ARGS"
+      # Number of logical CPUs, used as the default for `JOBS` when the caller doesn't set it.
+      # Portable across Linux (`nproc`), POSIX (`getconf`), and macOS (`sysctl`).
+      _CPU_COUNT:
+        sh: |-
+          nproc 2>/dev/null \
+            || getconf _NPROCESSORS_ONLN 2>/dev/null \
+            || sysctl -n hw.logicalcpu 2>/dev/null \
+            || echo 1
       JOBS: >-
-        {{default "" .JOBS}}
+        {{default ._CPU_COUNT .JOBS}}
       TARGETS:
         ref: "default (list) .TARGETS"
     requires:
@@ -154,7 +163,8 @@ tasks:
   # @param {string[]} [CMAKE_INSTALL_ARGS] Any additional arguments to pass to the CMake install
   # command.
   # @param {int} [CMAKE_JOBS] The maximum number of concurrent processes to use when building. If
-  # omitted, the native build tool's default number is used. See `man cmake`.
+  # omitted, defaults to the number of logical CPUs reported by the system. Falls back to 1 for a
+  # serial build if the CPU count cannot be determined.
   # @param {string} [CMAKE_SETTINGS_DIR] The directory where the project's CMake settings file
   # should be stored.
   # @param {string} [CMAKE_SOURCE_DIR=.] The path, within the extraction directory, containing the