diff --git a/scripts/verify_supply_chain_pins.py b/scripts/verify_supply_chain_pins.py
new file mode 100644
index 00000000..11fc8a52
--- /dev/null
+++ b/scripts/verify_supply_chain_pins.py
@@ -0,0 +1,108 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+import re
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+ACTION_SHA_RE = re.compile(
+    r"^\s*(?:-\s*)?uses:\s*([A-Za-z0-9_.-]+/[A-Za-z0-9_.-]+(?:/[A-Za-z0-9_./-]+)?)@([0-9a-f]{40})\s*(?:#.*)?$"
+)
+ACTION_USES_RE = re.compile(r"^\s*(?:-\s*)?uses:\s*(\S+)")
+DOCKER_FROM_RE = re.compile(r"^\s*FROM\s+(?:--platform=\S+\s+)?(\S+)", re.IGNORECASE)
+COMPOSE_IMAGE_RE = re.compile(r"^\s*image:\s*[\"']?([^\"'\s]+)")
+
+
+def _workflow_files() -> list[Path]:
+    files: list[Path] = []
+    for root in (ROOT / ".gitea/workflows", ROOT / ".github/workflows"):
+        if root.is_dir():
+            files.extend(sorted(root.glob("*.yml")))
+            files.extend(sorted(root.glob("*.yaml")))
+    return files
+
+
+def _check_workflows(violations: list[str]) -> None:
+    for path in _workflow_files():
+        for number, line in enumerate(path.read_text(encoding="utf-8").splitlines(), 1):
+            match = ACTION_USES_RE.match(line)
+            if not match:
+                continue
+            value = match.group(1)
+            if value.startswith("./"):
+                continue
+            if value.startswith("docker://"):
+                image = value.removeprefix("docker://")
+                if "@sha256:" not in image:
+                    violations.append(
+                        f"{path.relative_to(ROOT)}:{number}: docker action is not digest-pinned"
+                    )
+                continue
+            if not ACTION_SHA_RE.match(line):
+                violations.append(
+                    f"{path.relative_to(ROOT)}:{number}: action must use a full 40-char commit SHA: {value}"
+                )
+
+
+def _check_dockerfiles(violations: list[str]) -> None:
+    dockerfiles = (
+        ROOT / "backend/Dockerfile",
+        ROOT / "frontend/Dockerfile",
+        ROOT / "deploy/unraid/Dockerfile.all-in-one",
+    )
+    for path in dockerfiles:
+        if not path.is_file():
+            continue
+        for number, line in enumerate(path.read_text(encoding="utf-8").splitlines(), 1):
+            match = DOCKER_FROM_RE.match(line)
+            if not match:
+                continue
+            image = match.group(1)
+            if image == "scratch":
+                continue
+            if "${" in image:
+                violations.append(
+                    f"{path.relative_to(ROOT)}:{number}: dynamic external base image is not allowed"
+                )
+                continue
+            if "@sha256:" not in image:
+                violations.append(
+                    f"{path.relative_to(ROOT)}:{number}: base image must be digest-pinned: {image}"
+                )
+
+
+def _check_compose(violations: list[str]) -> None:
+    for relative in ("docker-compose.yml", "docker-compose.unraid.yml"):
+        path = ROOT / relative
+        if not path.is_file():
+            continue
+        for number, line in enumerate(path.read_text(encoding="utf-8").splitlines(), 1):
+            match = COMPOSE_IMAGE_RE.match(line)
+            if not match:
+                continue
+            image = match.group(1)
+            if image.startswith(("geointel-", "${")):
+                continue
+            if "@sha256:" not in image:
+                violations.append(
+                    f"{relative}:{number}: external image must be digest-pinned: {image}"
+                )
+
+
+def main() -> int:
+    violations: list[str] = []
+    _check_workflows(violations)
+    _check_dockerfiles(violations)
+    _check_compose(violations)
+    if violations:
+        print("Supply-chain pin violations:", file=sys.stderr)
+        for violation in violations:
+            print(f" - {violation}", file=sys.stderr)
+        return 1
+    print("Supply-chain pins passed.")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())