diff --git a/.github/workflows/release-manifest-contract.yml b/.github/workflows/release-manifest-contract.yml
index dc8567ae6..4aa353904 100644
--- a/.github/workflows/release-manifest-contract.yml
+++ b/.github/workflows/release-manifest-contract.yml
@@ -5,6 +5,8 @@ on:
     paths:
       - ".github/actionlint.yaml"
       - ".github/workflows/release-manifest-contract.yml"
+      - ".github/workflows/sentrux-quality-gate.yml"
+      - "tests/workflow_sentrux_shell_test.py"
       - ".github/workflows/release-coordinator.yml"
       - ".github/workflows/release-comprehensive.yml"
       - ".github/workflows/publish-npm.yml"
@@ -60,6 +62,8 @@ on:
     paths:
       - ".github/actionlint.yaml"
       - ".github/workflows/release-manifest-contract.yml"
+      - ".github/workflows/sentrux-quality-gate.yml"
+      - "tests/workflow_sentrux_shell_test.py"
       - ".github/workflows/release-coordinator.yml"
       - ".github/workflows/release-comprehensive.yml"
       - ".github/workflows/publish-npm.yml"
@@ -216,7 +220,7 @@ jobs:
       - name: actionlint (static workflow analysis)
         run: |
           set -euo pipefail
-          actionlint .github/workflows/publish-crates.yml .github/workflows/lsp-public-ci.yml .github/workflows/publish-lsp-crates.yml .github/workflows/lsp-producer.yml .github/workflows/lsp-publish.yml .github/workflows/release-coordinator.yml .github/workflows/release-sign.yml .github/workflows/release-comprehensive.yml .github/workflows/publish-npm.yml .github/workflows/publish-pypi.yml .github/workflows/publish-bun.yml .github/workflows/publish-tauri.yml .github/workflows/release-manifest-contract.yml
+          actionlint .github/workflows/sentrux-quality-gate.yml .github/workflows/publish-crates.yml .github/workflows/lsp-public-ci.yml .github/workflows/publish-lsp-crates.yml .github/workflows/lsp-producer.yml .github/workflows/lsp-publish.yml .github/workflows/release-coordinator.yml .github/workflows/release-sign.yml .github/workflows/release-comprehensive.yml .github/workflows/publish-npm.yml .github/workflows/publish-pypi.yml .github/workflows/publish-bun.yml .github/workflows/publish-tauri.yml .github/workflows/release-manifest-contract.yml
 
       - name: Parse workflow YAML
         run: |
@@ -231,6 +235,9 @@ jobs:
       - name: Run coordinator state-machine contract tests
         run: python -m unittest -v tests.release_coordinator_test
 
+      - name: Exercise Sentrux shell output handling
+        run: python -m unittest -v tests.workflow_sentrux_shell_test
+
       - name: Run workflow static contract tests
         run: python -m unittest -v tests.workflow_release_coordinator_contract_test
 
diff --git a/.github/workflows/sentrux-quality-gate.yml b/.github/workflows/sentrux-quality-gate.yml
index 31357199a..487a16be9 100644
--- a/.github/workflows/sentrux-quality-gate.yml
+++ b/.github/workflows/sentrux-quality-gate.yml
@@ -31,23 +31,25 @@ jobs:
           
           # Extract quality signal
           QUALITY=$(echo "$OUTPUT" | grep "Quality:" | awk '{print $2}')
-          echo "quality=$QUALITY" >> $GITHUB_OUTPUT
+          echo "quality=$QUALITY" >> "$GITHUB_OUTPUT"
           
           # Count violations
           VIOLATIONS=$(echo "$OUTPUT" | grep "violation(s) found" | awk '{print $2}')
-          echo "violations=$VIOLATIONS" >> $GITHUB_OUTPUT
+          echo "violations=$VIOLATIONS" >> "$GITHUB_OUTPUT"
           
           # Determine status
           if echo "$OUTPUT" | grep -q "✗.*violation"; then
-            echo "status=fail" >> $GITHUB_OUTPUT
+            echo "status=fail" >> "$GITHUB_OUTPUT"
           else
-            echo "status=pass" >> $GITHUB_OUTPUT
+            echo "status=pass" >> "$GITHUB_OUTPUT"
           fi
           
           # Save full output for comment
-          echo "output<<EOF" >> $GITHUB_OUTPUT
-          echo "$OUTPUT" >> $GITHUB_OUTPUT
-          echo "EOF" >> $GITHUB_OUTPUT
+          {
+            echo "output<<EOF"
+            echo "$OUTPUT"
+            echo "EOF"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Fetch Baseline (PR only)
         if: github.event_name == 'pull_request'
@@ -59,10 +61,10 @@ jobs:
             python3 -c "import json,sys; d=json.load(sys.stdin); print(d.get('content','').strip())" 2>/dev/null || echo "0")
           
           if [ "$BASELINE" = "0" ] || [ -z "$BASELINE" ]; then
-            echo "baseline=0" >> $GITHUB_OUTPUT
+            echo "baseline=0" >> "$GITHUB_OUTPUT"
             echo "No baseline found"
           else
-            echo "baseline=$BASELINE" >> $GITHUB_OUTPUT
+            echo "baseline=$BASELINE" >> "$GITHUB_OUTPUT"
             echo "Baseline: $BASELINE"
           fi
 
@@ -74,16 +76,16 @@ jobs:
           BASELINE=${{ steps.baseline.outputs.baseline }}
           
           if [ "$BASELINE" = "0" ] || [ -z "$BASELINE" ]; then
-            echo "delta=unknown" >> $GITHUB_OUTPUT
-            echo "degraded=false" >> $GITHUB_OUTPUT
+            echo "delta=unknown" >> "$GITHUB_OUTPUT"
+            echo "degraded=false" >> "$GITHUB_OUTPUT"
           else
             DELTA=$((CURRENT - BASELINE))
-            echo "delta=$DELTA" >> $GITHUB_OUTPUT
+            echo "delta=$DELTA" >> "$GITHUB_OUTPUT"
             
-            if [ $DELTA -lt -100 ]; then
-              echo "degraded=true" >> $GITHUB_OUTPUT
+            if [ "$DELTA" -lt -100 ]; then
+              echo "degraded=true" >> "$GITHUB_OUTPUT"
             else
-              echo "degraded=false" >> $GITHUB_OUTPUT
+              echo "degraded=false" >> "$GITHUB_OUTPUT"
             fi
           fi
 
@@ -133,33 +135,33 @@ jobs:
           
           COMMENT="## Sentrux Quality Gate $STATUS_ICON
 
-**Quality Signal:** $QUALITY / 10000
-**Violations:** $VIOLATIONS
-**Status:** $STATUS
-"
+          **Quality Signal:** $QUALITY / 10000
+          **Violations:** $VIOLATIONS
+          **Status:** $STATUS
+          "
           
           if [ "$DELTA" != "unknown" ]; then
             COMMENT="${COMMENT}**Delta:** $DELTA_ICON $DELTA points (baseline: $BASELINE)
-"
+          "
             if [ "$DEGRADED" = "true" ]; then
               COMMENT="${COMMENT}
-🔴 **Quality degraded by more than 100 points!**
-"
+          🔴 **Quality degraded by more than 100 points!**
+          "
             fi
           else
             COMMENT="${COMMENT}**Delta:** No baseline available
-"
+          "
           fi
           
           COMMENT="${COMMENT}
-<details>
-<summary>Full Report</summary>
+          <details>
+          <summary>Full Report</summary>
 
-\`\`\`
-${{ steps.sentrux.outputs.output }}
-\`\`\`
-</details>
-"
+          \`\`\`
+          ${{ steps.sentrux.outputs.output }}
+          \`\`\`
+          </details>
+          "
           
           # Post comment
           curl -s -X POST -H "Authorization: token $GITEA_TOKEN" \
diff --git a/tests/workflow_sentrux_shell_test.py b/tests/workflow_sentrux_shell_test.py
new file mode 100644
index 000000000..ba01b3320
--- /dev/null
+++ b/tests/workflow_sentrux_shell_test.py
@@ -0,0 +1,78 @@
+"""Run Sentrux workflow output handling in real Bash, without external services."""
+
+from pathlib import Path
+import os
+import subprocess
+import tempfile
+import unittest
+
+
+WORKFLOW = Path(__file__).resolve().parents[1] / ".github/workflows/sentrux-quality-gate.yml"
+
+
+def run_block(step):
+    """Extract one literal run block, rejecting content outside its indentation."""
+    body = WORKFLOW.read_text().split(f"      - name: {step}\n", 1)[1]
+    body = body.split("\n      - name:", 1)[0].split("        run: |\n", 1)[1]
+    lines = body.splitlines()
+    if any(line.strip() and not line.startswith("          ") for line in lines):
+        raise ValueError(f"Run block contains unindented content: {step}")
+    return "\n".join(line[10:] if line.startswith("          ") else line for line in lines) + "\n"
+
+
+class SentruxShellTests(unittest.TestCase):
+    def output_file(self, script, **variables):
+        """Execute a pure workflow fragment against a real file with spaces."""
+        with tempfile.TemporaryDirectory(prefix="sentrux workflow ") as folder:
+            output = Path(folder) / "step output.txt"
+            output.write_text("existing=value\n")
+            environment = dict(os.environ, GITHUB_OUTPUT=str(output), **variables)
+            subprocess.run(["bash", "-e", "-c", script], env=environment,
+                           check=True, capture_output=True, text=True, timeout=10)
+            return output.read_text()
+
+    def test_report_extraction_appends_exact_multiline_output(self):
+        # Exercise the real parsing/redirect fragment; do not replace the Sentrux binary.
+        script = run_block("Run Sentrux Check").split("# Extract quality signal\n", 1)[1]
+        for report, quality, count, status in [
+            ("Quality: 9600\n✓ 0 violation(s) found", "9600", "0", "pass"),
+            ("Quality: 8000\n✗ 2 violation(s) found\nDetail: a * literal [path]", "8000", "2", "fail"),
+        ]:
+            with self.subTest(status=status):
+                self.assertEqual(
+                    self.output_file(script, OUTPUT=report),
+                    f"existing=value\nquality={quality}\nviolations={count}\nstatus={status}\n"
+                    f"output<<EOF\n{report}\nEOF\n",
+                )
+
+    def test_baseline_redirect_preserves_zero_empty_and_known_values(self):
+        script = run_block("Fetch Baseline (PR only)").split('if [ "$BASELINE"', 1)[1]
+        script = 'if [ "$BASELINE"' + script
+        for value, expected in [("", "0"), ("0", "0"), ("9600", "9600")]:
+            with self.subTest(value=value):
+                self.assertEqual(self.output_file(script, BASELINE=value),
+                                 f"existing=value\nbaseline={expected}\n")
+
+    def test_delta_boundary_and_output_path(self):
+        template = run_block("Calculate Delta (PR only)")
+        for current, baseline, delta, degraded in [
+            ("9600", "0", "unknown", "false"),
+            ("9600", "", "unknown", "false"),
+            ("9600", "9600", "0", "false"),
+            ("9500", "9600", "-100", "false"),
+            ("9499", "9600", "-101", "true"),
+        ]:
+            with self.subTest(current=current, baseline=baseline):
+                script = template.replace("${{ steps.sentrux.outputs.quality }}", current)
+                script = script.replace("${{ steps.baseline.outputs.baseline }}", baseline)
+                self.assertEqual(self.output_file(script),
+                                 f"existing=value\ndelta={delta}\ndegraded={degraded}\n")
+
+    def test_comment_body_stays_inside_literal_run_block(self):
+        script = run_block("Post PR Comment")
+        self.assertIn("\n**Quality Signal:** $QUALITY / 10000\n", script)
+        self.assertIn("\n<details>\n<summary>Full Report</summary>\n", script)
+
+
+if __name__ == "__main__":
+    unittest.main()