diff --git a/.github/workflows/leaks.yml b/.github/workflows/leaks.yml
new file mode 100644
index 0000000..cb31c43
--- /dev/null
+++ b/.github/workflows/leaks.yml
@@ -0,0 +1,48 @@
+name: leaks
+
+# Secrets, private AI session links and local workstation paths stay out of
+# this public repository. The rules live in .gitleaks.toml.
+on:
+  push:
+    branches: [main]
+  pull_request:
+    types: [opened, edited, synchronize, reopened]
+
+permissions:
+  contents: read
+
+env:
+  GITLEAKS_VERSION: 8.30.1
+  GITLEAKS_SHA256: 551f6fc83ea457d62a0d98237cbad105af8d557003051f41f3e7ca7b3f2470eb
+
+jobs:
+  leaks:
+    name: leaks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Install gitleaks
+        run: |
+          archive="$RUNNER_TEMP/gitleaks.tar.gz"
+          curl -fsSLo "$archive" "https://github.com/gitleaks/gitleaks/releases/download/v${GITLEAKS_VERSION}/gitleaks_${GITLEAKS_VERSION}_linux_x64.tar.gz"
+          echo "${GITLEAKS_SHA256}  $archive" | sha256sum -c -
+          tar -xzf "$archive" -C "$RUNNER_TEMP" gitleaks
+
+      - name: Scan files
+        run: '"$RUNNER_TEMP/gitleaks" dir . --redact --no-banner'
+
+      # Edits to the description rerun this job, so the text is checked as posted.
+      - name: Scan pull request text and commit messages
+        if: github.event_name == 'pull_request'
+        env:
+          TITLE: ${{ github.event.pull_request.title }}
+          BODY: ${{ github.event.pull_request.body }}
+          BASE: ${{ github.event.pull_request.base.sha }}
+          HEAD: ${{ github.event.pull_request.head.sha }}
+        run: |
+          { printf '%s\n%s\n' "$TITLE" "$BODY"; git log --format=%B "$BASE..$HEAD"; } |
+            "$RUNNER_TEMP/gitleaks" stdin --redact --no-banner
diff --git a/.gitleaks.toml b/.gitleaks.toml
new file mode 100644
index 0000000..0a72adf
--- /dev/null
+++ b/.gitleaks.toml
@@ -0,0 +1,17 @@
+# Secret and privacy rules for this public repository: gitleaks's default
+# secret rules plus links and paths that must never be published. Add a rule
+# here to extend every check (lefthook and CI read this file).
+[extend]
+useDefault = true
+
+[[rules]]
+id = "private-ai-session-link"
+description = "Private AI session link or session trailer"
+regex = '''(?i)(claude\.ai/(code|chat|share|project)/|Claude-Session:|chatgpt\.com/(c|share|codex)/)'''
+keywords = ["claude", "chatgpt"]
+
+[[rules]]
+id = "local-workstation-path"
+description = "Local workstation home directory path"
+regex = '''(/Users|/home)/[A-Za-z0-9_.-]+/'''
+keywords = ["/users/", "/home/"]
diff --git a/lefthook.yml b/lefthook.yml
new file mode 100644
index 0000000..99e289e
--- /dev/null
+++ b/lefthook.yml
@@ -0,0 +1,11 @@
+# Secrets, private AI session links and local paths, by .gitleaks.toml.
+# Install with `lefthook install`; CI runs the same rules.
+pre-commit:
+  jobs:
+    - name: leaks
+      run: gitleaks git --pre-commit --staged --redact --no-banner
+
+commit-msg:
+  jobs:
+    - name: leaks
+      run: gitleaks stdin --redact --no-banner < {1}