diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 7914d26..74b931c 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -13,6 +13,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - name: Install validator dependencies
+        run: python -m pip install -r requirements.txt
       - name: Validate JSON and public repo gate
         run: |
           python -m json.tool schemas/trust-action-receipt.schema.json >/dev/null
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..332413d
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+jsonschema[format]>=4,<5
diff --git a/tools/check-public-task-repo.sh b/tools/check-public-task-repo.sh
index 09df9c7..76ff083 100755
--- a/tools/check-public-task-repo.sh
+++ b/tools/check-public-task-repo.sh
@@ -2,7 +2,7 @@
 set -euo pipefail
 fail() { echo "❌ $1" >&2; exit 1; }
 
-required_files=(README.md SPEC.md PILOT_ACCESS.md ADOPTION.md SECURITY.md CONTRIBUTING.md GOVERNANCE.md VERSIONING.md schemas/trust-action-receipt.schema.json examples/remote-worker.receipt.json docs/public-vs-pilot.md docs/production-checklist.md docs/standardization-roadmap.md tools/validate-receipts.py)
+required_files=(README.md SPEC.md PILOT_ACCESS.md ADOPTION.md SECURITY.md CONTRIBUTING.md GOVERNANCE.md VERSIONING.md requirements.txt schemas/trust-action-receipt.schema.json examples/remote-worker.receipt.json docs/public-vs-pilot.md docs/production-checklist.md docs/standardization-roadmap.md tools/validate-receipts.py)
 
 for f in "${required_files[@]}"; do
   [ -f "$f" ] || fail "Missing required file: $f"
diff --git a/tools/validate-receipts.py b/tools/validate-receipts.py
index 516f621..dd47a28 100755
--- a/tools/validate-receipts.py
+++ b/tools/validate-receipts.py
@@ -2,22 +2,84 @@
 import json
 from pathlib import Path
 
-required = ["receipt_type", "scenario_id", "actor", "subject", "action", "decision", "evidence", "issued_at"]
-valid_decisions = {"allow", "deny", "review_required", "freeze", "revoke"}
-ok = True
-
-for path in sorted(Path("examples").glob("*.json")):
-    data = json.loads(path.read_text(encoding="utf-8"))
-    missing = [k for k in required if k not in data]
-    if missing:
-        print(f"❌ {path}: missing {', '.join(missing)}")
-        ok = False
-    elif data["receipt_type"] != "trust_action_receipt":
-        print(f"❌ {path}: invalid receipt_type")
-        ok = False
-    elif data["decision"] not in valid_decisions:
-        print(f"❌ {path}: invalid decision")
-        ok = False
-    else:
-        print(f"✅ {path}: valid public draft receipt")
-raise SystemExit(0 if ok else 1)
+try:
+    from jsonschema import Draft202012Validator, FormatChecker
+except ImportError as exc:
+    raise SystemExit("Missing dependency. Run: python3 -m pip install -r requirements.txt") from exc
+
+
+SCHEMA_PATH = Path("schemas/trust-action-receipt.schema.json")
+EXAMPLES_DIR = Path("examples")
+DEMO_SIGNATURE = "demo-signature-not-production"
+FORBIDDEN_PUBLIC_MARKERS = (
+    "BEGIN " + "PRIVATE KEY",
+    "PRIVATE_KEY" + "=",
+    "SECRET" + "=",
+    "sk_" + "live_",
+    "pk_" + "live_",
+    "AKIA",
+    "scoped key " + "value",
+    "production signing " + "key",
+    "real customer " + "receipt",
+)
+
+
+def load_json(path):
+    return json.loads(path.read_text(encoding="utf-8"))
+
+
+def public_safety_errors(path, receipt):
+    errors = []
+    text = path.read_text(encoding="utf-8")
+
+    for marker in FORBIDDEN_PUBLIC_MARKERS:
+        if marker in text:
+            errors.append(f"contains forbidden public marker: {marker}")
+
+    signature = receipt.get("signature")
+    if signature != DEMO_SIGNATURE:
+        errors.append("public examples must keep the demo signature marker")
+
+    if receipt.get("receipt_id"):
+        errors.append("public examples must not claim a production receipt_id")
+
+    if receipt.get("policy_ref"):
+        errors.append("public examples must not include production policy_ref")
+
+    if receipt.get("proof_ref"):
+        errors.append("public examples must not include production proof_ref")
+
+    return errors
+
+
+def main():
+    schema = load_json(SCHEMA_PATH)
+    validator = Draft202012Validator(schema, format_checker=FormatChecker())
+    paths = sorted(EXAMPLES_DIR.glob("*.receipt.json"))
+    ok = True
+
+    if not paths:
+        print("❌ examples: no *.receipt.json files found")
+        return 1
+
+    for path in paths:
+        receipt = load_json(path)
+        schema_errors = sorted(validator.iter_errors(receipt), key=lambda err: list(err.path))
+        safety_errors = public_safety_errors(path, receipt)
+
+        if schema_errors or safety_errors:
+            ok = False
+            print(f"❌ {path}: invalid public demo receipt")
+            for err in schema_errors:
+                field = ".".join(str(part) for part in err.path) or "<root>"
+                print(f"   schema: {field}: {err.message}")
+            for err in safety_errors:
+                print(f"   safety: {err}")
+            continue
+
+        print(f"✅ {path}: schema-valid public demo receipt")
+
+    return 0 if ok else 1
+
+
+raise SystemExit(main())