diff --git a/.github/workflows/secret-scan.yml b/.github/workflows/secret-scan.yml
index e652404..ea2aeff 100644
--- a/.github/workflows/secret-scan.yml
+++ b/.github/workflows/secret-scan.yml
@@ -1,38 +1,80 @@
-# Secret-scan backstop. The allowlist export is the gate; this is the seatbelt.
-# Uses the gitleaks BINARY (Apache-2.0, free) — NOT gitleaks-action, which
-# requires a paid GITLEAKS_LICENSE for organization repos. Scans the current tree
-# (--no-git) so it blocks NEW secrets/infra strings without re-flagging old history.
+# Secret-scan backstop. Historical exceptions are exact reviewed fingerprints.
 name: secret-scan
 on:
   push:
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   gitleaks:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
+    timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v4
-      - name: install gitleaks
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          fetch-depth: 0
+      - name: Install checksum-verified Gitleaks
+        shell: bash
         run: |
-          curl -sSL -o /tmp/gl.tgz \
+          set -euo pipefail
+          curl --fail --show-error --silent --location -o /tmp/gitleaks.tar.gz \
             https://github.com/gitleaks/gitleaks/releases/download/v8.30.1/gitleaks_8.30.1_linux_x64.tar.gz
-          tar -xzf /tmp/gl.tgz -C /tmp gitleaks
+          echo "551f6fc83ea457d62a0d98237cbad105af8d557003051f41f3e7ca7b3f2470eb  /tmp/gitleaks.tar.gz" | sha256sum --check
+          tar -xzf /tmp/gitleaks.tar.gz -C /tmp gitleaks
           sudo install /tmp/gitleaks /usr/local/bin/gitleaks
-      - name: scan working tree
-        run: gitleaks detect --source . --no-git --config .gitleaks.toml --redact --verbose
+      - name: Scan complete reachable history
+        run: gitleaks git . --log-opts=HEAD --config .gitleaks.toml --redact --verbose
+      - name: Prove broad placeholder labels cannot suppress a secret
+        shell: bash
+        run: |
+          set -euo pipefail
+          tmp="$(mktemp -d)"
+          git -C "$tmp" init --quiet
+          git -C "$tmp" config user.name "Secret Scan Control"
+          git -C "$tmp" config user.email "security-control@example.invalid"
+          half='0123456789abcdef0123456789abcdef'
+          printf 'example_private_key = 0x%s%s\n' "$half" "$half" > "$tmp/leak.txt"
+          git -C "$tmp" add leak.txt
+          git -C "$tmp" commit --quiet -m "synthetic leak"
+          if gitleaks git "$tmp" --log-opts=HEAD \
+            --config "$GITHUB_WORKSPACE/.gitleaks.toml" --redact; then
+            echo "::error::Gitleaks accepted the committed negative-control secret"
+            exit 1
+          fi
+          echo "Gitleaks rejected the committed negative-control secret as expected"
 
   infra-strings:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
+    timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v4
-      - name: block infra / local-path leaks
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Reject operational infrastructure strings
+        shell: bash
         run: |
-          set -e
-          patt='172\.(30|31)\.[0-9]+\.[0-9]+|/Users/[a-z0-9._-]+/|aipgcoregen|BEGIN (RSA |EC |OPENSSH |)PRIVATE KEY'
-          if git grep -nIE "$patt" -- . ':(exclude).gitleaks.toml' ':(exclude)**/secret-scan.yml'; then
-            echo "::error::infra/secret string found above — scrub before merge"; exit 1
+          set -euo pipefail
+          pattern='172\.(30|31)\.[0-9]+\.[0-9]+|/Users/[a-z0-9._-]+/|aipgcoregen|aipg-transient|BEGIN ((RSA|EC|OPENSSH) )?PRIVATE KEY'
+          for sample in \
+            '172.''30''.1.2' \
+            '/Us''ers/operator/' \
+            'aipgcore''gen' \
+            'aipg-trans''ient' \
+            'BEGIN ''PRIVATE KEY' \
+            'BEGIN OPEN''SSH PRIVATE KEY'; do
+            if ! printf '%s\n' "$sample" | grep -Eq "$pattern"; then
+              echo "::error::infra-string scanner failed its negative control"
+              exit 1
+            fi
+          done
+          result=0
+          matches="$(git grep -nIE "$pattern" -- . ':(exclude).gitleaks.toml' ':(exclude)**/secret-scan.yml')" || result=$?
+          if [ "$result" -gt 1 ]; then
+            echo "::error::infra-string scanner failed to execute"
+            exit "$result"
           fi
-          if git ls-files | grep -iE 'security_audit|audit_report'; then
-            echo "::error::audit report file tracked — must not ship"; exit 1
+          if [ "$result" -eq 0 ]; then
+            printf '%s\n' "$matches"
+            echo "::error::operational infrastructure or secret material found above"
+            exit 1
           fi
-          echo "infra-string scan clean"
diff --git a/.gitleaksignore b/.gitleaksignore
new file mode 100644
index 0000000..239a2c5
--- /dev/null
+++ b/.gitleaksignore
@@ -0,0 +1 @@
+8992df8f44f8ef8827a4973141033d2799baa4d8:AGENTS.md:aipg-local-dev-path:54
diff --git a/AGENTS.md b/AGENTS.md
index e8a27ca..35739c6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -51,6 +51,8 @@ submit/poll). The retired horde `/api/v2` async queue is NOT used. Published to
 - **`tests/`** — pytest suite (`test_client.py`, `test_grid.py`); uses `respx` to mock HTTP.
   Owned in its own AGENTS.md.
 - **`pyproject.toml`** — setuptools build, `src/` layout, deps, pytest config.
+- **`.github/workflows/secret-scan.yml`, `.gitleaks.toml`, and `.gitleaksignore`** —
+  checksum-verified complete-history secret scanning with exact historical fingerprints only.
 - `dist/`, `.venv/`, `*.egg-info/` — build/vendored artifacts; do not edit or document.
 
 ## Local Contracts
@@ -75,6 +77,8 @@ submit/poll). The retired horde `/api/v2` async queue is NOT used. Published to
 
 - `pytest` (install with `pip install -e ".[test]"`). Client and raw-Grid HTTP
   are mocked via `respx`, so no live Grid is required.
+- `gitleaks git . --log-opts=HEAD --config .gitleaks.toml --redact --verbose`
+  scans the complete history reachable from the candidate commit.
 
 ## Child DOX Index