diff --git a/.github/workflows/reusable.yml b/.github/workflows/reusable.yml
index e4855b91..db200a7e 100644
--- a/.github/workflows/reusable.yml
+++ b/.github/workflows/reusable.yml
@@ -95,6 +95,31 @@ on:
         required: false
         type: string
         default: ''
+      b2_targets:
+        description: "B2 targets to build, e.g. 'libs/foo/test//bar'. Defaults to auto-detecting the tests"
+        required: false
+        type: string
+        default: ''
+      b2_defines:
+        description: "Preprocessor defines to add"
+        required: false
+        type: string
+        default: ''
+      b2_link:
+        description: "Build shared and/or static"
+        required: false
+        type: string
+        default: 'shared,static'
+      b2_variant:
+        description: "Variants/Optimization level(s) to build"
+        required: false
+        type: string
+        default: 'debug,release'
+      library_folder:
+        description: "Name of the subfolder of the Boost tree the library should be. Will be determined by the value of 'key' in meta/libraries.json."
+        required: false
+        type: string
+        default: ''
     secrets:
       CODECOV_TOKEN:
         description: "The token for covecov.io; if defined then coverage will be collected."
@@ -113,8 +138,6 @@ concurrency:
 env:
   GIT_FETCH_JOBS: 8
   NET_RETRY_COUNT: 5
-  B2_VARIANT: debug,release
-  B2_LINK: shared,static
   LCOV_BRANCH_COVERAGE: ${{ inputs.branch_coverage && '1' || '0' }}
   CODECOV_NAME: Github Actions
 
@@ -426,22 +449,19 @@ jobs:
       - name: Setup Boost
         run: source ci/github/install.sh
         env:
+          ENABLE_REFLECTION: ${{ matrix.reflection }}
+          XCODE_APP: ${{matrix.xcode_app}}
           B2_ADDRESS_MODEL: ${{matrix.address-model}}
           B2_COMPILER: ${{matrix.compiler}}
           B2_CXXFLAGS: ${{matrix.cxxflags}}
           B2_CXXSTD: ${{matrix.cxxstd}}
-          ENABLE_REFLECTION: ${{ matrix.reflection }}
           B2_SANITIZE: ${{matrix.sanitize}}
           B2_STDLIB: ${{matrix.stdlib}}
-          # Optional. Variables set here (to non-empty) will override the top-level environment variables
-          B2_DEFINES: ${{matrix.defines}}
-          B2_VARIANT: ${{matrix.variant}}
-          B2_LINK: ${{matrix.link}}
-          XCODE_APP: ${{matrix.xcode_app}}
-          # More entries can be added in the same way, see the B2_ARGS assignment in ci/enforce.sh for the possible keys.
-          # Set the (B2) target(s) to build, defaults to the test folder of the current library
-          # Can alternatively be done like this in the build step or in the build command of the build step, e.g. `run: B2_TARGETS=libs/$SELF/doc ci/build.sh`
-          # B2_TARGETS: libs/foo/test//bar
+          B2_DEFINES: ${{inputs.b2_defines}}
+          B2_LINK: ${{inputs.b2_link}}
+          B2_VARIANT: ${{inputs.b2_variant}}
+          SELF: ${{inputs.library_folder}}
+
 
       - name: Setup coverage collection
         if: matrix.coverage
@@ -450,6 +470,8 @@ jobs:
       - name: Run tests
         if: '!matrix.coverity'
         run: ci/build.sh
+        env:
+          B2_TARGETS: ${{inputs.b2_targets}}
         # inherits environment from install.sh step
 
       - name: Show config.log
@@ -587,30 +609,39 @@ jobs:
         run: ci\github\install.bat
         env:
           B2_TOOLSET: ${{matrix.toolset}}
+          SELF: ${{inputs.library_folder}}
 
-      - name: Run tests
-        if: '!matrix.coverage'
-        run: ci\build.bat
+      - name: Determine B2 arguments
+        run: |
+          # Use Bash which is more flexible than CMD and we can reuse the logic
+          . ci/enforce.sh
+          echo "B2_FULL_ARGS=${B2_ARGS[@]}" >> "$GITHUB_ENV"
+          echo "SELF=$SELF" >> "$GITHUB_ENV"
+          if [[ -z "$B2_TARGETS" ]]; then
+            B2_TARGETS=libs/$SELF/test
+          fi
+          echo "B2_TARGETS=$B2_TARGETS" >> "$GITHUB_ENV"
+          echo "SELF=$SELF" >> "$GITHUB_ENV"
+        shell: bash
         env:
           B2_TOOLSET: ${{matrix.toolset}}
           B2_TARGET_OS: ${{matrix.target-os}}
           B2_CXXSTD: ${{matrix.cxxstd}}
           B2_ADDRESS_MODEL: ${{matrix.address-model}}
-          B2_DEFINES: ${{matrix.defines}}
-          B2_VARIANT: ${{matrix.variant}}
-          B2_LINK: ${{matrix.link}}
+          B2_DEFINES: ${{inputs.b2_defines}}
+          B2_LINK: ${{inputs.b2_link}}
+          B2_VARIANT: ${{inputs.b2_variant}}
+          B2_TARGETS: ${{inputs.b2_targets}}
+          SELF: ${{inputs.library_folder}}
+
+      - name: Run tests
+        if: '!matrix.coverage'
+        run: ci\build.bat
 
       - name: Collect coverage
         shell: powershell
         if: matrix.coverage
         run: ci\opencppcoverage.ps1
-        env:
-          B2_TOOLSET: ${{matrix.toolset}}
-          B2_CXXSTD: ${{matrix.cxxstd}}
-          B2_ADDRESS_MODEL: ${{matrix.address-model}}
-          B2_DEFINES: ${{matrix.defines}}
-          B2_VARIANT: ${{matrix.variant}}
-          B2_LINK: ${{matrix.link}}
 
       - name: Upload coverage
         if: matrix.coverage
@@ -719,9 +750,9 @@ jobs:
           B2_CXXSTD: ${{matrix.cxxstd}}
           B2_SANITIZE: ${{matrix.sanitize}}
           B2_STDLIB: ${{matrix.stdlib}}
-          B2_DEFINES: ${{matrix.defines}}
-          B2_VARIANT: ${{matrix.variant}}
-          B2_LINK: ${{matrix.link}}
+          B2_DEFINES: ${{inputs.b2_defines}}
+          B2_LINK: ${{inputs.b2_link}}
+          B2_VARIANT: ${{inputs.b2_variant}}
 
       - name: Run tests
         run: ci/build.sh
diff --git a/ci/build.bat b/ci/build.bat
index 8d9fcbfb..512970be 100644
--- a/ci/build.bat
+++ b/ci/build.bat
@@ -15,6 +15,11 @@ IF "%B2_CI_VERSION%" == "0" (
 
 IF DEFINED ADDPATH (SET "PATH=%ADDPATH%%PATH%")
 
+cd %BOOST_ROOT%
+
+set SELF_S=%SELF:\=/%
+IF NOT DEFINED B2_TARGETS (SET B2_TARGETS=libs/!SELF_S!/test)
+
 SET B2_TOOLCXX=toolset=%B2_TOOLSET%
 
 IF DEFINED B2_CXXSTD (SET B2_CXXSTD=cxxstd=%B2_CXXSTD%)
@@ -26,8 +31,6 @@ IF DEFINED B2_TARGET_OS (SET B2_TARGET_OS=target-os=%B2_TARGET_OS%)
 IF DEFINED B2_LINK (SET B2_LINK=link=%B2_LINK%)
 IF DEFINED B2_VARIANT (SET B2_VARIANT=variant=%B2_VARIANT%)
 
-set SELF_S=%SELF:\=/%
-IF NOT DEFINED B2_TARGETS (SET B2_TARGETS=libs/!SELF_S!/test)
 IF NOT DEFINED B2_JOBS (SET B2_JOBS=3)
 
 REM clang-win requires to use the linker for the manifest
@@ -39,10 +42,13 @@ IF "%B2_TOOLSET%" == "clang-win" (
     )
 )
 
-cd %BOOST_ROOT%
-
 IF DEFINED SCRIPT (
     call libs\%SELF%\%SCRIPT%
+) ELSE IF DEFINED B2_FULL_ARGS (
+    REM Echo the complete build command to the build log
+    ECHO b2 --abbreviate-paths %B2_TARGETS% %B2_FULL_ARGS%
+    REM Now go build...
+    b2 --abbreviate-paths %B2_TARGETS% %B2_FULL_ARGS%
 ) ELSE (
     REM Echo the complete build command to the build log
     ECHO b2 --abbreviate-paths %B2_TARGETS% %B2_TOOLCXX% %B2_CXXSTD% %B2_CXXFLAGS% %B2_DEFINES% %B2_INCLUDE% %B2_THREADING% %B2_ADDRESS_MODEL% %B2_TARGET_OS% %B2_LINK% %B2_VARIANT% -j%B2_JOBS% %B2_FLAGS%
diff --git a/ci/enforce.sh b/ci/enforce.sh
index 50711430..eef6d599 100755
--- a/ci/enforce.sh
+++ b/ci/enforce.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 #
 # Copyright 2017 - 2019 James E. King III
-# Copyright 2020 - 2025 Alexander Grund
+# Copyright 2020 - 2026 Alexander Grund
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at
 #      http://www.boost.org/LICENSE_1_0.txt)
@@ -60,8 +60,13 @@ fi
 
 # default parallel build jobs: number of CPUs available + 1
 if [ -z "${B2_JOBS:-}" ]; then
-    pythonexecutable=$(get_python_executable)
-    cpus=$(grep -c 'processor' /proc/cpuinfo || $pythonexecutable -c 'import multiprocessing as mp; print(mp.cpu_count())' || echo "2")
+    if ! cpus=$(grep -c 'processor' /proc/cpuinfo); then
+        if pythonexecutable=$(get_python_executable); then
+            cpus=$($pythonexecutable -c 'import multiprocessing as mp; print(mp.cpu_count())' || echo "2")
+        else
+            cpus=2
+        fi
+    fi
     export B2_JOBS=$((cpus + 1))
 fi
 
@@ -97,14 +102,9 @@ if ((${B2_CI_VERSION:-1} > 0)); then
 
   B2_ARGS=(
       ${B2_TOOLSET:+"toolset=$B2_TOOLSET"}
-      "cxxstd=$B2_CXXSTD"
+      ${B2_CXXSTD:+"cxxstd=$B2_CXXSTD"}
       ${B2_CXXFLAGS:+"cxxflags=$B2_CXXFLAGS"}
-  )
-  append_b2_args B2_DEFINES define
-  append_b2_args B2_INCLUDE include
-  # shellcheck disable=SC2206
-  B2_ARGS=(
-      "${B2_ARGS[@]}"
+      ${B2_TARGET_OS:+"target-os=$B2_TARGET_OS"}
       ${B2_LINKFLAGS:+"linkflags=$B2_LINKFLAGS"}
       ${B2_TESTFLAGS:-}
       ${B2_ADDRESS_MODEL:+address-model=$B2_ADDRESS_MODEL}
@@ -117,8 +117,16 @@ if ((${B2_CI_VERSION:-1} > 0)); then
       ${B2_TSAN:+thread-sanitizer=norecover}
       ${B2_UBSAN:+undefined-sanitizer=norecover}
       -j"${B2_JOBS}"
-      ${B2_FLAGS:-}
   )
+  append_b2_args B2_DEFINES define
+  append_b2_args B2_INCLUDE include
+  # clang-win requires to use the linker for the manifest
+  if [[ ${B2_TOOLSET:-} == "clang-win" ]]; then
+    B2_ARGS+=(embed-manifest-via=linker)
+  fi
+
+  # shellcheck disable=SC2206
+  B2_ARGS+=(${B2_FLAGS:-})
 else
   # Legacy codepath for compatibility for for old versions of the .github/*.yml files:
   # In (most) variables the prefix (such as "cxxflags=" for B2_CXXFLAGS) was included in the value, so it isn't added (again) here
diff --git a/test/Jamfile b/test/Jamfile
index 74e8ec81..d73c175a 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -16,10 +16,12 @@ local B2_ADDRESS_MODEL = [ os.environ B2_ADDRESS_MODEL ] ;
 local B2_CXXFLAGS = [ os.environ B2_CXXFLAGS ] ;
 local B2_CXXSTD = [ os.environ B2_CXXSTD ] ;
 local B2_DEFINES = [ os.environ B2_DEFINES ] ;
+local B2_FULL_ARGS = [ os.environ B2_FULL_ARGS ] ;
 local B2_INCLUDE = [ os.environ B2_INCLUDE ] ;
 local B2_JOBS = [ os.environ B2_JOBS ] ;
 local B2_LINK = [ os.environ B2_LINK ] ;
 local B2_LINKFLAGS = [ os.environ B2_LINKFLAGS ] ;
+local B2_TARGETS = [ os.environ B2_TARGETS ] ;
 local B2_TESTFLAGS = [ os.environ B2_TESTFLAGS ] ;
 local B2_THREADING = [ os.environ B2_THREADING ] ;
 local B2_TOOLSET = [ os.environ B2_TOOLSET ] ;
@@ -33,10 +35,12 @@ ECHO "  B2_ADDRESS_MODEL:" $(B2_ADDRESS_MODEL) ;
 ECHO "  B2_CXXFLAGS:" $(B2_CXXFLAGS) ;
 ECHO "  B2_CXXSTD:" $(B2_CXXSTD) ;
 ECHO "  B2_DEFINES:" $(B2_DEFINES) ;
+ECHO "  B2_FULL_ARGS:" $(B2_FULL_ARGS) ;
 ECHO "  B2_INCLUDE:" $(B2_INCLUDE) ;
 ECHO "  B2_JOBS:" $(B2_JOBS) ;
 ECHO "  B2_LINK:" $(B2_LINK) ;
 ECHO "  B2_LINKFLAGS:" $(B2_LINKFLAGS) ;
+ECHO "  B2_TARGETS:" $(B2_TARGETS) ;
 ECHO "  B2_TESTFLAGS:" $(B2_TESTFLAGS) ;
 ECHO "  B2_THREADING:" $(B2_THREADING) ;
 ECHO "  B2_TOOLSET:" $(B2_TOOLSET) ;