diff --git a/.github/workflows/shen-c.yml b/.github/workflows/shen-c.yml
index cb7fbf3..012051d 100644
--- a/.github/workflows/shen-c.yml
+++ b/.github/workflows/shen-c.yml
@@ -14,7 +14,13 @@ jobs:
     timeout-minutes: 20
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        include:
+          - os: ubuntu-latest
+            cc: clang-18
+            ar: llvm-ar-18
+          - os: macos-latest
+            cc: clang
+            ar: ar
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -30,18 +36,21 @@ jobs:
           go-version: '1.27.x'
           cache: false
       - name: Verify native C toolchain
+        env:
+          CC: ${{ matrix.cc }}
+          AR: ${{ matrix.ar }}
         run: |
-          command -v clang
-          clang --version
-          command -v ar
-          ar --version || true
+          command -v "$CC"
+          "$CC" --version
+          command -v "$AR"
+          "$AR" --version || true
       - name: Build released native RC CLI
         env:
-          CC: clang
-          AR: ar
+          CC: ${{ matrix.cc }}
+          AR: ${{ matrix.ar }}
           RC_LTO: '0'
           PKG_CONFIG: /nonexistent/no-boehm-or-pkg-config
-        run: make -C shen-c -j2
+        run: make -C shen-c CC="$CC" AR="$AR" -j2
       - name: Test adapter and supported live controls
         working-directory: bifrost
         env:
diff --git a/docs/shen-c-rc-20261018.md b/docs/shen-c-rc-20261018.md
index 1adce1d..5ac6cbe 100644
--- a/docs/shen-c-rc-20261018.md
+++ b/docs/shen-c-rc-20261018.md
@@ -78,3 +78,17 @@ fixture commands run. This fixes installer tests launched by Git hooks. The
 installer tests with a foreign repository, worktree and index in their environment;
 all passed, and both repositories retained identical HEAD, index and bare settings.
 This follow-up is separate from the frozen CLI/corpus assessment above.
+
+## Post-release fix candidate
+
+The two runtime failures above are corrected in Shen-C's
+[`fix/bifrost-corpus-gaps` candidate](https://github.com/pyrex41/shen-c/tree/fix/bifrost-corpus-gaps).
+The complete unchanged corpus now reports **70 executed PASS, zero failures,
+two capability skips and two kernel skips** against that candidate. Its
+[qualification record](https://github.com/pyrex41/shen-c/blob/fix/bifrost-corpus-gaps/docs/qualification/bifrost-corpus-gaps-20261018.md)
+binds source, generated kernel, binaries and corpus identities, and records
+fatal sanitizer plus full 136/0 suite results. These corrections are newer than
+v0.3.0; this adapter's released installation pin is intentionally unchanged.
+The C artifact's literal runtime-load dependency gap is also corrected in the
+[Yggdrasil follow-up](https://github.com/pyrex41/yggdrasil/blob/fix/shen-c-native-rc/docs/dynamic-load-20261018.md).
+The frozen v0.3.0 assessment above is retained as historical release evidence.