diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 08d257f..0521c3d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,6 +22,7 @@ jobs:
       - run: pnpm run lint
       - run: pnpm run test
       - run: pnpm run typecheck
+      - run: pnpm run test:ci-workflow
       - name: OpenAPI document is up to date with the committed JSON Schemas
         run: pnpm --filter @ddn/api run openapi:check
       - name: Merkle V1 golden vectors are up to date with the committed implementation
@@ -151,7 +152,12 @@ jobs:
     # cross-architecture validation and does not overwrite policy.wasm,
     # manifest.json, or the profile either way.
     #
-    # Explicitly experimental and non-blocking (continue-on-error: true):
+    # Explicitly experimental and non-blocking: the validation step records
+    # its result, emits a visible Actions warning and uploads diagnostics, but
+    # exits successfully so a known experimental crash does not mark an
+    # otherwise green commit with a misleading red check. A success here is
+    # therefore NOT evidence that amd64 reproducibility passed; the step
+    # summary and diagnostics artifact remain the source of that result.
     # native amd64 currently fails nondeterministically with SIGSEGV in
     # host build-script binaries (proc-macro2, serde_json, ...) -- real,
     # reproduced on this native GitHub-hosted amd64 runner AND under QEMU,
@@ -163,7 +169,6 @@ jobs:
     # (not full rebuild loops or core dumps) for that investigation.
     name: Experimental cross-architecture validation (linux/amd64, non-blocking)
     runs-on: ubuntu-latest
-    continue-on-error: true
     steps:
       - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
       - uses: pnpm/action-setup@f40ffcd9367d9f12939873eb1018b921a783ffaa # v4
@@ -174,12 +179,36 @@ jobs:
       - run: pnpm install --frozen-lockfile
       - run: pnpm --filter @ddn/schemas run build
       - run: node scripts/gen-reason-codes.mjs
-      - run: ./scripts/policy-reproducibility.sh
-      - name: Collect diagnostics (failure only)
-        if: failure()
+      - name: Run experimental amd64 validation without gating the commit
+        id: amd64-validation
+        shell: bash
+        run: |
+          set +e
+          ./scripts/policy-reproducibility.sh
+          status=$?
+          set -e
+
+          if [ "$status" -eq 0 ]; then
+            echo "failed=false" >> "$GITHUB_OUTPUT"
+            echo "### Experimental linux/amd64 validation: PASS" >> "$GITHUB_STEP_SUMMARY"
+          else
+            echo "failed=true" >> "$GITHUB_OUTPUT"
+            echo "::warning title=Experimental linux/amd64 validation failed::Known non-blocking amd64 toolchain investigation failed with exit code $status; diagnostics will be uploaded. The linux/arm64 release gate is unaffected."
+            {
+              echo "### Experimental linux/amd64 validation: DID NOT PASS"
+              echo
+              echo "Exit code: $status. This check is diagnostic and does not gate the linux/arm64 release."
+            } >> "$GITHUB_STEP_SUMMARY"
+          fi
+
+          exit 0
+      - name: Collect diagnostics (experimental failure only)
+        if: steps.amd64-validation.outputs.failed == 'true'
+        continue-on-error: true
         run: ./scripts/diagnose-amd64-crash.sh
-      - name: Upload diagnostics (failure only)
-        if: failure()
+      - name: Upload diagnostics (experimental failure only)
+        if: steps.amd64-validation.outputs.failed == 'true'
+        continue-on-error: true
         uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: amd64-crash-diagnostics
diff --git a/package.json b/package.json
index 73513a4..ab25837 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,7 @@
     "verify:milestone-2": "./scripts/verify-milestone-2.sh",
     "public-release-check": "node scripts/public-release-check.mjs --mode git-worktree",
     "test:public-release": "node --test scripts/public-snapshot-files.test.mjs && node scripts/public-release-check.mjs --self-test",
+    "test:ci-workflow": "node --test scripts/ci-workflow.test.mjs",
     "secrets:gitleaks": "node scripts/gitleaks-gate.mjs",
     "secrets:trufflehog": "node scripts/trufflehog-gate.mjs",
     "sbom": "node scripts/generate-sbom.mjs",
diff --git a/scripts/ci-workflow.test.mjs b/scripts/ci-workflow.test.mjs
new file mode 100644
index 0000000..495196a
--- /dev/null
+++ b/scripts/ci-workflow.test.mjs
@@ -0,0 +1,29 @@
+#!/usr/bin/env node
+// SPDX-License-Identifier: Apache-2.0
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import test from 'node:test';
+
+const workflow = readFileSync(new URL('../.github/workflows/ci.yml', import.meta.url), 'utf8');
+const amd64Job = workflow.match(
+  /  cross-architecture-amd64:\n([\s\S]*?)(?=\n  [a-z][a-z0-9-]*:\n)/,
+)?.[1];
+
+test('experimental amd64 validation reports failure without producing a red commit check', () => {
+  assert.ok(amd64Job, 'cross-architecture-amd64 job must exist');
+  assert.doesNotMatch(
+    amd64Job,
+    /^    continue-on-error: true$/m,
+    'job-level continue-on-error leaves a red check-run even when the workflow succeeds',
+  );
+  assert.match(amd64Job, /id: amd64-validation/);
+  assert.match(amd64Job, /echo "failed=true" >> "\$GITHUB_OUTPUT"/);
+  assert.match(amd64Job, /::warning title=Experimental linux\/amd64 validation failed/);
+  assert.match(amd64Job, /^          exit 0$/m);
+  assert.match(
+    amd64Job,
+    /if: steps\.amd64-validation\.outputs\.failed == 'true'/,
+    'diagnostics must still run when the experimental validation fails',
+  );
+});
+