diff --git a/.github/sic-audit-trigger b/.github/sic-audit-trigger
new file mode 100644
index 0000000000..1096183dcc
--- /dev/null
+++ b/.github/sic-audit-trigger
@@ -0,0 +1 @@
+trigger patched SIC audit
diff --git a/.github/workflows/openai-sic-immutable-audit.yml b/.github/workflows/openai-sic-immutable-audit.yml
new file mode 100644
index 0000000000..bf07a0930d
--- /dev/null
+++ b/.github/workflows/openai-sic-immutable-audit.yml
@@ -0,0 +1,125 @@
+name: OpenAI immutable SIC proof audit
+
+on:
+  pull_request:
+    branches: [main]
+    paths:
+      - '.github/workflows/openai-sic-immutable-audit.yml'
+      - '.github/sic-audit-trigger'
+
+permissions:
+  contents: read
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    timeout-minutes: 50
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          ref: 7aeef3c2aca76d413f94d13ebf6044e9b6c1d712
+          fetch-depth: 1
+      - name: Confirm immutable SIC proof commit
+        run: test "$(git rev-parse HEAD)" = 7aeef3c2aca76d413f94d13ebf6044e9b6c1d712
+      - name: Apply four deterministic phase-normalization repairs
+        run: |
+          python3 - <<'PY'
+          from pathlib import Path
+          import re
+          p = Path('FormalConjectures/OpenQuantumProblems/23.lean')
+          s = p.read_text()
+
+          def replace_between(start_pat, end_pat, replacement):
+              global s
+              pattern = re.escape(start_pat) + r'.*?(?=' + re.escape(end_pat) + r')'
+              s2, n = re.subn(pattern, replacement.rstrip() + '\n\n', s, count=1, flags=re.S)
+              if n != 1:
+                  raise SystemExit(f'failed replacement for {start_pat}: {n}')
+              s = s2
+
+          replace_between(
+              '@[simp] private lemma normSq_qubit_offdiag_star_omega_pow_two_audit',
+              '@[simp] private lemma overlap_three_two_star_pow_audit',
+              '''@[simp] private lemma normSq_qubit_offdiag_star_omega_pow_two_audit :
+    Complex.normSq ((1 / 3 : ℂ) + (2 / 3 : ℂ) *
+      ((starRingEnd ℂ) ω) ^ 2) = (1 / 3 : ℝ) := by
+  change Complex.normSq ((1 / 3 : ℂ) + (2 / 3 : ℂ) *
+    ((ω ^ 2) * (ω ^ 2))) = (1 / 3 : ℝ)
+  rw [omega_sq_mul_omega_sq_audit]
+  exact normSq_qubit_offdiag_omega_audit''')
+
+          replace_between(
+              '@[simp] private lemma overlap_three_two_star_pow_audit',
+              '/-- The tetrahedral qubit SIC family has the correct constant pairwise overlap. -/',
+              '''@[simp] private lemma overlap_three_two_star_pow_audit :
+    Complex.normSq ((1 / 3 : ℂ) + (tetraB : ℂ) *
+      ((starRingEnd ℂ) ω) ^ 2 * ((tetraB : ℂ) * ω)) = (1 / 3 : ℝ) := by
+  change Complex.normSq ((1 / 3 : ℂ) + (tetraB : ℂ) *
+    ((ω ^ 2) * (ω ^ 2)) * ((tetraB : ℂ) * ω)) = (1 / 3 : ℝ)
+  rw [omega_sq_mul_omega_sq_audit]
+  exact overlap_three_two_simplified_audit''')
+
+          replace_between(
+              '@[simp] private lemma q3_normSq_half_add_half_mul_star_omega_pow_two',
+              '@[simp] private lemma q3_normSq_half_add_hesseS_star_omega_pow_two_mul_hesseS_omega',
+              '''@[simp] private lemma q3_normSq_half_add_half_mul_star_omega_pow_two :
+    Complex.normSq ((1 / 2 : ℂ) + (1 / 2 : ℂ) *
+      ((starRingEnd ℂ) ω) ^ 2) = (1 / 4 : ℝ) := by
+  change Complex.normSq ((1 / 2 : ℂ) + (1 / 2 : ℂ) *
+    ((ω ^ 2) * (ω ^ 2))) = (1 / 4 : ℝ)
+  rw [q3_omega_sq_mul_omega_sq]
+  exact q3_normSq_half_add_half_mul_omega''')
+
+          replace_between(
+              '@[simp] private lemma q3_normSq_half_add_hesseS_star_omega_pow_two_mul_hesseS_omega',
+              '@[simp] private lemma q3_normSq_half_mul_omega_sq_add_half',
+              '''@[simp] private lemma q3_normSq_half_add_hesseS_star_omega_pow_two_mul_hesseS_omega :
+    Complex.normSq ((1 / 2 : ℂ) + (hesseS : ℂ) *
+      ((starRingEnd ℂ) ω) ^ 2 * ((hesseS : ℂ) * ω)) = (1 / 4 : ℝ) := by
+  change Complex.normSq ((1 / 2 : ℂ) + (hesseS : ℂ) *
+    ((ω ^ 2) * (ω ^ 2)) * ((hesseS : ℂ) * ω)) = (1 / 4 : ℝ)
+  rw [q3_omega_sq_mul_omega_sq]
+  exact q3_normSq_half_add_hesseS_omega_mul_hesseS_omega''')
+
+          p.write_text(s)
+          PY
+          git diff --check
+          git diff -- FormalConjectures/OpenQuantumProblems/23.lean > /tmp/sic-four-repairs.patch
+      - name: Install pinned Lean toolchain
+        run: |
+          curl -fsSL https://raw.githubusercontent.com/leanprover/elan/master/elan-init.sh | sh -s -- -y --default-toolchain none
+          echo "$HOME/.elan/bin" >> "$GITHUB_PATH"
+      - uses: actions/cache@v4
+        with:
+          path: |
+            .lake/packages
+            .lake/build
+          key: sic-immutable-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('lean-toolchain', 'lake-manifest.json', 'lakefile.toml') }}
+          restore-keys: sic-immutable-${{ runner.os }}-${{ runner.arch }}-
+      - name: Fetch compiled dependencies
+        run: lake exe cache get
+      - name: Compile patched registered canonical module
+        run: |
+          set -o pipefail
+          lake build FormalConjectures.OpenQuantumProblems.«23» 2>&1 | tee /tmp/sic-immutable-build.log
+      - name: Audit exact theorem axioms
+        run: |
+          cat > /tmp/SICImmutableAxioms.lean <<'EOF'
+          import FormalConjectures.OpenQuantumProblems.«23»
+          #print axioms OpenQuantumProblem23.qubitSICFamily_pairwise
+          #print axioms OpenQuantumProblem23.hasSICPOVM_two
+          #print axioms OpenQuantumProblem23.hesseFamily_pairwise
+          #print axioms OpenQuantumProblem23.hasSICPOVM_three
+          EOF
+          lake env lean /tmp/SICImmutableAxioms.lean 2>&1 | tee /tmp/sic-immutable-axioms.log
+          ! grep -E 'sorryAx|Lean\.ofReduce|Lean\.ofReduceBool|Lean\.trustCompiler' /tmp/sic-immutable-axioms.log
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: sic-immutable-${{ github.run_id }}
+          path: |
+            FormalConjectures/OpenQuantumProblems/23.lean
+            /tmp/sic-four-repairs.patch
+            /tmp/sic-immutable-build.log
+            /tmp/sic-immutable-axioms.log
+          if-no-files-found: warn