diff --git a/.github/workflows/health-70-validate-sync-manifest.yml b/.github/workflows/health-70-validate-sync-manifest.yml
index daddd1322..d6bc525fa 100644
--- a/.github/workflows/health-70-validate-sync-manifest.yml
+++ b/.github/workflows/health-70-validate-sync-manifest.yml
@@ -18,6 +18,7 @@ on:
       - '.github/workflows/**'
       - '.github/codex/**'
       - '.github/scripts/**'
+      - 'scripts/check_workflow_action_pins.py'
       - 'templates/consumer-repo/**'
   push:
     branches: [main]
@@ -26,6 +27,7 @@ on:
       - '.github/workflows/**'
       - '.github/codex/**'
       - '.github/scripts/**'
+      - 'scripts/check_workflow_action_pins.py'
       - 'templates/consumer-repo/**'
 
 permissions:
@@ -66,6 +68,21 @@ jobs:
             --manifest ".github/sync-manifest.yml" \
             --source "sync-manifest" \
             --strict
+      - name: Validate workflow action pins
+        run: |
+          mkdir -p artifacts/workflow-action-pins
+          python scripts/check_workflow_action_pins.py \
+            .github/workflows/agents-verify-to-new-pr.yml \
+            templates/consumer-repo/.github/workflows \
+            --output-json artifacts/workflow-action-pins/workflow-action-pins.json \
+            --output-md artifacts/workflow-action-pins/workflow-action-pins.md
+      - name: Upload action pin contract
+        if: ${{ always() }}
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        with:
+          name: workflow-action-pins
+          path: artifacts/workflow-action-pins/
+          if-no-files-found: warn
       - name: Comment on PR
         if: failure() && github.event_name == 'pull_request'
         uses: actions/github-script@v9
diff --git a/scripts/check_workflow_action_pins.py b/scripts/check_workflow_action_pins.py
new file mode 100644
index 000000000..94c49cdb6
--- /dev/null
+++ b/scripts/check_workflow_action_pins.py
@@ -0,0 +1,219 @@
+#!/usr/bin/env python3
+"""Validate that selected workflow action references are commit-SHA pinned."""
+
+from __future__ import annotations
+
+import argparse
+import json
+import re
+import sys
+from pathlib import Path
+from typing import Any
+
+SCHEMA = "workflow-action-pins/v1"
+SHA_RE = re.compile(r"^[0-9a-fA-F]{40}$")
+USES_RE = re.compile(r"^\s*(?:-\s*)?uses:\s*(?P<uses>[^\s#]+)(?P<comment>\s*#.*)?$")
+VERSION_COMMENT_RE = re.compile(r"#\s*v\d+(?:[.\w-]+)?\b")
+
+
+def _iter_workflow_files(paths: list[Path]) -> list[Path]:
+    files: list[Path] = []
+    seen: set[Path] = set()
+    for path in paths:
+        if path.is_dir():
+            candidates = sorted(
+                child
+                for child in path.rglob("*")
+                if child.is_file() and child.suffix in {".yml", ".yaml"}
+            )
+        else:
+            candidates = [path]
+        for candidate in candidates:
+            resolved = candidate.resolve()
+            if resolved not in seen:
+                seen.add(resolved)
+                files.append(candidate)
+    return files
+
+
+def _is_checked_action(action: str, prefixes: tuple[str, ...]) -> bool:
+    return any(action.startswith(prefix) for prefix in prefixes)
+
+
+def _format_path(path: Path) -> str:
+    try:
+        return path.relative_to(Path.cwd()).as_posix()
+    except ValueError:
+        return path.as_posix()
+
+
+def check_file(
+    path: Path,
+    *,
+    prefixes: tuple[str, ...] = ("actions/",),
+    require_version_comment: bool = True,
+) -> tuple[int, list[dict[str, Any]]]:
+    """Return checked action count and pinning issues for one workflow file."""
+    issues: list[dict[str, Any]] = []
+    checked_count = 0
+    try:
+        lines = path.read_text(encoding="utf-8").splitlines()
+    except OSError as exc:
+        return 0, [
+            {
+                "path": _format_path(path),
+                "line": 0,
+                "uses": "",
+                "action": "",
+                "ref": "",
+                "reason": "read-error",
+                "message": f"Unable to read workflow file: {exc}",
+            }
+        ]
+
+    for line_number, line in enumerate(lines, 1):
+        match = USES_RE.match(line)
+        if not match:
+            continue
+
+        uses = match.group("uses")
+        action, separator, ref = uses.rpartition("@")
+        if not separator or not _is_checked_action(action, prefixes):
+            continue
+
+        checked_count += 1
+        comment = match.group("comment") or ""
+        if not SHA_RE.match(ref):
+            issues.append(
+                {
+                    "path": _format_path(path),
+                    "line": line_number,
+                    "uses": uses,
+                    "action": action,
+                    "ref": ref,
+                    "reason": "floating-ref",
+                    "message": "Action reference must use a 40-character commit SHA.",
+                }
+            )
+            continue
+
+        if require_version_comment and not VERSION_COMMENT_RE.search(comment):
+            issues.append(
+                {
+                    "path": _format_path(path),
+                    "line": line_number,
+                    "uses": uses,
+                    "action": action,
+                    "ref": ref,
+                    "reason": "missing-version-comment",
+                    "message": "Pinned action SHA must keep a readable '# vN' version comment.",
+                }
+            )
+
+    return checked_count, issues
+
+
+def build_report(
+    paths: list[Path],
+    *,
+    prefixes: tuple[str, ...] = ("actions/",),
+    require_version_comment: bool = True,
+) -> dict[str, Any]:
+    files = _iter_workflow_files(paths)
+    issues: list[dict[str, Any]] = []
+    checked_uses_count = 0
+    for path in files:
+        file_count, file_issues = check_file(
+            path,
+            prefixes=prefixes,
+            require_version_comment=require_version_comment,
+        )
+        checked_uses_count += file_count
+        issues.extend(file_issues)
+
+    return {
+        "schema": SCHEMA,
+        "status": "pass" if not issues else "fail",
+        "checked_files": [_format_path(path) for path in files],
+        "checked_file_count": len(files),
+        "checked_uses_count": checked_uses_count,
+        "prefixes": list(prefixes),
+        "require_version_comment": require_version_comment,
+        "issue_count": len(issues),
+        "issues": issues,
+    }
+
+
+def format_markdown(report: dict[str, Any]) -> str:
+    lines = [
+        "# Workflow Action Pin Report",
+        "",
+        f"- Schema: `{report['schema']}`",
+        f"- Status: `{report['status']}`",
+        f"- Files checked: {report['checked_file_count']}",
+        f"- Action references checked: {report['checked_uses_count']}",
+        f"- Issues: {report['issue_count']}",
+    ]
+    if report["issues"]:
+        lines.extend(["", "| Path | Line | Uses | Reason |", "| --- | ---: | --- | --- |"])
+        for issue in report["issues"]:
+            lines.append(
+                "| {path} | {line} | `{uses}` | {reason} |".format(
+                    path=issue["path"],
+                    line=issue["line"],
+                    uses=issue["uses"],
+                    reason=issue["reason"],
+                )
+            )
+    return "\n".join(lines) + "\n"
+
+
+def _write_outputs(
+    report: dict[str, Any], output_json: Path | None, output_md: Path | None
+) -> None:
+    if output_json is not None:
+        output_json.parent.mkdir(parents=True, exist_ok=True)
+        output_json.write_text(
+            json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8"
+        )
+    if output_md is not None:
+        output_md.parent.mkdir(parents=True, exist_ok=True)
+        output_md.write_text(format_markdown(report), encoding="utf-8")
+
+
+def parse_args(argv: list[str] | None = None) -> argparse.Namespace:
+    parser = argparse.ArgumentParser(
+        description="Validate selected workflow action references are SHA-pinned."
+    )
+    parser.add_argument("paths", nargs="+", type=Path, help="Workflow files or directories")
+    parser.add_argument(
+        "--prefix",
+        action="append",
+        dest="prefixes",
+        default=None,
+        help="Action prefix to enforce, e.g. actions/ (repeatable)",
+    )
+    parser.add_argument(
+        "--no-require-version-comment",
+        action="store_true",
+        help="Allow pinned SHAs without '# vN' comments.",
+    )
+    parser.add_argument("--output-json", type=Path, help="Write machine-readable report JSON")
+    parser.add_argument("--output-md", type=Path, help="Write markdown report")
+    return parser.parse_args(argv)
+
+
+def main(argv: list[str] | None = None) -> int:
+    args = parse_args(argv)
+    report = build_report(
+        args.paths,
+        prefixes=tuple(args.prefixes or ["actions/"]),
+        require_version_comment=not args.no_require_version_comment,
+    )
+    _write_outputs(report, args.output_json, args.output_md)
+    print(format_markdown(report), end="")
+    return 0 if report["status"] == "pass" else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/tests/scripts/test_check_workflow_action_pins.py b/tests/scripts/test_check_workflow_action_pins.py
new file mode 100644
index 000000000..3eeb44d06
--- /dev/null
+++ b/tests/scripts/test_check_workflow_action_pins.py
@@ -0,0 +1,139 @@
+import json
+from pathlib import Path
+
+from scripts import check_workflow_action_pins
+
+PINNED_CHECKOUT = "de0fac2e4500dabe0009e67214ff5f5447ce83dd"
+PINNED_GITHUB_SCRIPT = "3a2844b7e9c422d3c10d287c895573f7108da1b3"
+
+
+def test_build_report_accepts_sha_pinned_actions_with_version_comments(tmp_path: Path) -> None:
+    workflow = tmp_path / "workflow.yml"
+    workflow.write_text(
+        f"""
+name: pinned
+on: push
+jobs:
+  test:
+    steps:
+      - uses: actions/checkout@{PINNED_CHECKOUT} # v6
+      - name: Script
+        uses: actions/github-script@{PINNED_GITHUB_SCRIPT} # v9
+""",
+        encoding="utf-8",
+    )
+
+    report = check_workflow_action_pins.build_report([workflow])
+
+    assert report["status"] == "pass"
+    assert report["checked_uses_count"] == 2
+    assert report["issues"] == []
+
+
+def test_build_report_flags_floating_action_refs(tmp_path: Path) -> None:
+    workflow = tmp_path / "workflow.yml"
+    workflow.write_text(
+        """
+name: floating
+on: push
+jobs:
+  test:
+    steps:
+      - uses: actions/checkout@v6
+""",
+        encoding="utf-8",
+    )
+
+    report = check_workflow_action_pins.build_report([workflow])
+
+    assert report["status"] == "fail"
+    assert report["issues"][0]["reason"] == "floating-ref"
+    assert report["issues"][0]["uses"] == "actions/checkout@v6"
+
+
+def test_build_report_flags_sha_without_readable_version_comment(tmp_path: Path) -> None:
+    workflow = tmp_path / "workflow.yml"
+    workflow.write_text(
+        f"""
+name: missing-comment
+on: push
+jobs:
+  test:
+    steps:
+      - uses: actions/checkout@{PINNED_CHECKOUT}
+""",
+        encoding="utf-8",
+    )
+
+    report = check_workflow_action_pins.build_report([workflow])
+
+    assert report["status"] == "fail"
+    assert report["issues"][0]["reason"] == "missing-version-comment"
+
+
+def test_build_report_ignores_local_actions_and_reusable_workflows(tmp_path: Path) -> None:
+    workflow = tmp_path / "workflow.yml"
+    workflow.write_text(
+        """
+name: ignored
+on: push
+jobs:
+  test:
+    steps:
+      - uses: ./.github/actions/setup-api-client
+  reusable:
+    uses: stranske/Workflows/.github/workflows/reusable-codex-run.yml@main
+""",
+        encoding="utf-8",
+    )
+
+    report = check_workflow_action_pins.build_report([workflow])
+
+    assert report["status"] == "pass"
+    assert report["checked_uses_count"] == 0
+
+
+def test_main_writes_machine_readable_outputs(tmp_path: Path) -> None:
+    workflow = tmp_path / "workflow.yml"
+    output_json = tmp_path / "report.json"
+    output_md = tmp_path / "report.md"
+    workflow.write_text(
+        f"""
+name: pinned
+on: push
+jobs:
+  test:
+    steps:
+      - uses: actions/checkout@{PINNED_CHECKOUT} # v6
+""",
+        encoding="utf-8",
+    )
+
+    exit_code = check_workflow_action_pins.main(
+        [
+            str(workflow),
+            "--output-json",
+            str(output_json),
+            "--output-md",
+            str(output_md),
+        ]
+    )
+
+    assert exit_code == 0
+    assert json.loads(output_json.read_text(encoding="utf-8"))["schema"] == (
+        "workflow-action-pins/v1"
+    )
+    assert "Workflow Action Pin Report" in output_md.read_text(encoding="utf-8")
+
+
+def test_current_consumer_template_actions_are_pinned() -> None:
+    report = check_workflow_action_pins.build_report(
+        [
+            Path(".github/workflows/agents-verify-to-new-pr.yml"),
+            Path("templates/consumer-repo/.github/workflows"),
+        ]
+    )
+
+    assert report["status"] == "pass"
+    assert report["checked_file_count"] >= 30
+    assert report["checked_uses_count"] >= 1