diff --git a/doc_steward/cli.py b/doc_steward/cli.py
index 27f40b11..0c64df93 100644
--- a/doc_steward/cli.py
+++ b/doc_steward/cli.py
@@ -23,6 +23,7 @@
 from .artefact_index_validator import check_artefact_index
 from .dap_validator import check_dap_compliance
 from .doc_authority_manifest import check_doc_authority_manifest
+from .drift_sweep_issue_creator import run as run_drift_sweep_issue_creator
 from .entrypoint_freshness_sweep import (
     DEFAULT_LABELS as ENTRYPOINT_FRESHNESS_LABELS,
 )
@@ -316,6 +317,17 @@ def cmd_check_manifest(args: argparse.Namespace) -> int:
     return 0
 
 
+def cmd_drift_sweep_preview(args: argparse.Namespace) -> int:
+    """Run drift sweep preview (dry-run only, no GitHub mutation)."""
+    run_drift_sweep_issue_creator(
+        Path(args.repo_root).resolve(),
+        output_dir=args.output_dir,
+        print_json=args.json,
+        parent_link=args.parent_link,
+    )
+    return 0
+
+
 def main() -> int:
     parser = argparse.ArgumentParser(
         prog="doc_steward.cli", description="LifeOS Documentation Steward CLI"
@@ -387,6 +399,17 @@ def main() -> int:
     )
     p_entrypoint_sweep.set_defaults(func=cmd_entrypoint_freshness_sweep)
 
+    # drift-sweep-preview
+    p_drift = subparsers.add_parser(
+        "drift-sweep-preview",
+        help="Preview advisory documentation drift sweep issues (dry-run only, no GitHub mutation)",
+    )
+    p_drift.add_argument("repo_root", help="Repository root directory")
+    p_drift.add_argument("--output-dir", default=None, help="Output dir for preview files")
+    p_drift.add_argument("--json", action="store_true", help="Print JSON preview to stdout")
+    p_drift.add_argument("--parent-link", default=None, help="URL to parent tracking issue")
+    p_drift.set_defaults(func=cmd_drift_sweep_preview)
+
     # protocols-structure-check
     p_protocols = subparsers.add_parser(
         "protocols-structure-check", help="Validate docs/02_protocols/ structure"
diff --git a/doc_steward/drift_sweep_issue_creator.py b/doc_steward/drift_sweep_issue_creator.py
new file mode 100644
index 00000000..e97147c9
--- /dev/null
+++ b/doc_steward/drift_sweep_issue_creator.py
@@ -0,0 +1,266 @@
+"""
+Self-contained drift sweep issue preview creator.
+
+Read-only dry-run module that detects advisory documentation drift via
+freshness_validator.check_entrypoint_freshness() and produces structured
+JSON previews and human-readable markdown summaries without any GitHub
+mutation, sweep_lib dependency, or external state.
+"""
+
+from __future__ import annotations
+
+import argparse
+import hashlib
+import json
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+
+from .freshness_validator import check_entrypoint_freshness
+
+SWEEP_ID = "inventory-hygiene-sweep"
+TARGET = "lifeos-doc-entrypoint"
+CHECK_ID = "readme-entrypoint-freshness"
+SCHEMA_VERSION = "drift-sweep-preview-v1"
+
+
+def _fingerprint(
+    sweep_id: str,
+    target: str,
+    check_id: str,
+    evidence: str,
+    authority_class: str,
+) -> str:
+    """Deterministic SHA-256 fingerprint for a drift class group."""
+    raw = "|".join([sweep_id, target, check_id, evidence, authority_class])
+    return hashlib.sha256(raw.encode("utf-8")).hexdigest()[:16]
+
+
+def _normalize_evidence(findings: list[dict]) -> str:
+    """Stable normalized text for one drift-class group.
+
+    Sorts findings by id, lowercases all evidence, collapses whitespace.
+    """
+    parts = []
+    for finding in sorted(findings, key=lambda f: str(f.get("id", ""))):
+        ev = str(finding.get("evidence", ""))
+        parts.append(" ".join(ev.split()).strip().lower())
+    return " | ".join(parts)
+
+
+def _group_findings(findings: list[dict]) -> dict[str, list[dict]]:
+    """Group findings by their 'id' key, preserving first-occurrence order."""
+    groups: dict[str, list[dict]] = {}
+    for finding in findings:
+        fid = str(finding.get("id", ""))
+        if fid not in groups:
+            groups[fid] = []
+        groups[fid].append(finding)
+    return groups
+
+
+def _compute_fingerprints(groups: dict[str, list[dict]]) -> dict[str, str]:
+    """Compute per-class fingerprints for each drift class."""
+    fingerprints: dict[str, str] = {}
+    for fid, findings in groups.items():
+        evidence = _normalize_evidence(findings)
+        authority_class = str(findings[0].get("authority_class", ""))
+        fingerprints[fid] = _fingerprint(
+            SWEEP_ID,
+            TARGET,
+            CHECK_ID,
+            evidence,
+            authority_class,
+        )
+    return fingerprints
+
+
+def build_preview(
+    findings: list[dict],
+    parent_link: str | None = None,
+) -> dict:
+    """Build structured JSON preview from detector findings."""
+    groups = _group_findings(findings)
+    fingerprints = _compute_fingerprints(groups)
+    now = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")
+
+    classes = {}
+    for fid, fgroup in groups.items():
+        classes[fid] = {
+            "count": len(fgroup),
+            "fingerprint": fingerprints.get(fid, ""),
+        }
+
+    findings_by_class: dict[str, list[dict]] = {}
+    for fid, fgroup in groups.items():
+        findings_by_class[fid] = [dict(f) for f in fgroup]
+
+    return {
+        "sweep_metadata": {
+            "sweep_id": SWEEP_ID,
+            "target": TARGET,
+            "check_id": CHECK_ID,
+            "generation_timestamp": now,
+            "schema_version": SCHEMA_VERSION,
+        },
+        "summary": {
+            "total_findings": len(findings),
+            "total_classes": len(groups),
+            "classes": classes,
+        },
+        "findings_by_class": findings_by_class,
+        "fingerprints": fingerprints,
+        "parent_link": parent_link,
+        "receipt": {
+            "tool": "drift_sweep_issue_creator",
+            "version": "1",
+            "mutated": False,
+            "dry_run": True,
+            "generated_at": now,
+        },
+    }
+
+
+def _footer() -> str:
+    return (
+        "---\n\n"
+        "_Generated by `drift_sweep_issue_creator`. "
+        "No files were mutated. This is a dry-run preview._"
+    )
+
+
+def render_markdown(preview: dict) -> str:
+    """Render a drift preview dict as human-readable markdown."""
+    lines: list[str] = []
+    sweep_md = preview.get("sweep_metadata", {})
+    summary = preview.get("summary", {})
+
+    lines.append("# Advisory Documentation Drift Sweep Preview")
+    lines.append("")
+    lines.append(f"- **Sweep:** `{sweep_md.get('sweep_id')}`")
+    lines.append(f"- **Target:** `{sweep_md.get('target')}`")
+    lines.append(f"- **Check:** `{sweep_md.get('check_id')}`")
+    lines.append(f"- **Generated:** {sweep_md.get('generation_timestamp')}")
+    lines.append("")
+
+    parent_link = preview.get("parent_link")
+    if parent_link:
+        lines.append(f"- **Parent issue:** {parent_link}")
+        lines.append("")
+
+    total_findings = summary.get("total_findings", 0)
+
+    if total_findings == 0:
+        lines.append("## No drift findings detected.")
+        lines.append("")
+        lines.append(_footer())
+        return "\n".join(lines)
+
+    total_classes = summary.get("total_classes", 0)
+    lines.append(f"**{total_findings} finding(s) across {total_classes} drift class(es)**")
+    lines.append("")
+    lines.append("| Drift Class | Count | Fingerprint |")
+    lines.append("|---|---|---|")
+
+    classes = summary.get("classes", {})
+    for fid, info in classes.items():
+        lines.append(f"| `{fid}` | {info.get('count', 0)} | `{info.get('fingerprint', '')}` |")
+    lines.append("")
+
+    findings_by_class = preview.get("findings_by_class", {})
+    for fid in classes:
+        fgroup = findings_by_class.get(fid, [])
+        lines.append("---")
+        lines.append("")
+        fp = classes.get(fid, {}).get("fingerprint", "")
+        lines.append(f"## {fid} ({len(fgroup)} finding(s))")
+        lines.append("")
+        lines.append(f"- **Fingerprint:** `{fp}`")
+
+        for finding in fgroup:
+            lines.append(f"- **Severity:** {finding.get('severity', 'N/A')}")
+            paths = finding.get("paths", [])
+            if paths:
+                lines.append(f"- **Paths:** {', '.join(str(p) for p in paths)}")
+            lines.append(f"- **Evidence:** {finding.get('evidence', 'N/A')}")
+            recovery = finding.get("recommended_recovery", "")
+            if recovery:
+                lines.append(f"- **Recovery:** {recovery}")
+            authority = finding.get("authority_class", "")
+            if authority:
+                lines.append(f"- **Authority:** {authority}")
+        lines.append("")
+
+    lines.append(_footer())
+    return "\n".join(lines)
+
+
+def write_preview(preview: dict, output_dir: str | Path) -> list[Path]:
+    """Write JSON and MD preview files to output_dir.
+
+    Creates output_dir if needed. Writes timestamped copies plus _latest files.
+    Returns list of written file paths.
+    """
+    output_path = Path(output_dir)
+    output_path.mkdir(parents=True, exist_ok=True)
+
+    now = datetime.now(timezone.utc)
+    timestamp = now.strftime("%Y%m%dT%H%M%SZ")
+
+    json_path = output_path / f"drift_sweep_preview_{timestamp}.json"
+    md_path = output_path / f"drift_sweep_preview_{timestamp}.md"
+
+    json_text = json.dumps(preview, indent=2, sort_keys=False) + "\n"
+    md_text = render_markdown(preview) + "\n"
+
+    json_path.write_text(json_text, encoding="utf-8")
+    md_path.write_text(md_text, encoding="utf-8")
+
+    latest_json = output_path / "drift_sweep_preview_latest.json"
+    latest_md = output_path / "drift_sweep_preview_latest.md"
+
+    latest_json.write_text(json_text, encoding="utf-8")
+    latest_md.write_text(md_text, encoding="utf-8")
+
+    return [json_path, md_path, latest_json, latest_md]
+
+
+def run(
+    repo_root: str | Path,
+    output_dir: str | Path | None = None,
+    print_json: bool = False,
+    parent_link: str | None = None,
+) -> dict:
+    """Orchestrate: detect -> build_preview -> optional write/print."""
+    findings = check_entrypoint_freshness(repo_root)
+    preview = build_preview(findings, parent_link=parent_link)
+
+    if output_dir is not None:
+        write_preview(preview, output_dir)
+
+    if print_json:
+        print(json.dumps(preview, indent=2, sort_keys=False))
+
+    return preview
+
+
+def main(argv: list[str] | None = None) -> int:
+    """Standalone CLI entry point."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("repo_root", help="Repository root directory")
+    parser.add_argument("--output-dir", default=None, help="Output dir for preview files")
+    parser.add_argument("--json", action="store_true", help="Print JSON preview to stdout")
+    parser.add_argument("--parent-link", default=None, help="URL to parent tracking issue")
+    args = parser.parse_args(argv)
+
+    run(
+        Path(args.repo_root).resolve(),
+        output_dir=args.output_dir,
+        print_json=args.json,
+        parent_link=args.parent_link,
+    )
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/tests_doc/test_drift_sweep_issue_creator.py b/tests_doc/test_drift_sweep_issue_creator.py
new file mode 100644
index 00000000..8b08c0af
--- /dev/null
+++ b/tests_doc/test_drift_sweep_issue_creator.py
@@ -0,0 +1,531 @@
+"""Tests for drift_sweep_issue_creator — dry-run preview builder for entrypoint freshness drift."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from doc_steward.drift_sweep_issue_creator import (
+    CHECK_ID,
+    SCHEMA_VERSION,
+    SWEEP_ID,
+    TARGET,
+    _compute_fingerprints,
+    _group_findings,
+    _normalize_evidence,
+    build_preview,
+    main,
+    render_markdown,
+    write_preview,
+)
+from doc_steward.freshness_validator import check_entrypoint_freshness
+
+# ---------------------------------------------------------------------------
+# Fixture helpers (local copy — avoids cross-test-module import coupling)
+# ---------------------------------------------------------------------------
+
+CLEAN_README = """# LifeOS
+
+**Current Status**: Live COO operations.
+
+Repo canon wins on conflict. The strategic corpus and wiki are derived.
+
+1. [docs/INDEX.md](docs/INDEX.md)
+2. [onboarding](docs/08_manuals/LifeOS_Operator_Onboarding.md)
+3. [state](docs/11_admin/LIFEOS_STATE.md)
+4. [architecture](docs/00_foundations/LifeOS%20Target%20Architecture%20v2.3c.md)
+"""
+
+CLEAN_REGISTRY = """doc_groups:
+  - id: canonical-root-navigation
+    authority: canonical
+    paths:
+      - docs/INDEX.md
+  - id: derived-strategic-corpus
+    authority: derived
+    paths:
+      - docs/LifeOS_Strategic_Corpus.md
+"""
+
+
+def _write_entrypoint_fixture(
+    root: Path, readme: str | None = None, registry: str | None = None
+) -> None:
+    (root / "docs" / "11_admin").mkdir(parents=True, exist_ok=True)
+    (root / "docs" / "08_manuals").mkdir(parents=True, exist_ok=True)
+    (root / "docs" / "00_foundations").mkdir(parents=True, exist_ok=True)
+    (root / "config" / "docs").mkdir(parents=True, exist_ok=True)
+    (root / "docs" / "INDEX.md").write_text("# Index\n", encoding="utf-8")
+    (root / "docs" / "LifeOS_Strategic_Corpus.md").write_text(
+        "# Derived corpus\n", encoding="utf-8"
+    )
+    (root / "docs" / "11_admin" / "LIFEOS_STATE.md").write_text(
+        "# LifeOS State\n\n## COO Bootstrap Campaign\nLive COO operational.\n",
+        encoding="utf-8",
+    )
+    (root / "README.md").write_text(
+        readme or CLEAN_README,
+        encoding="utf-8",
+    )
+    (root / "config" / "docs" / "authority_registry.yaml").write_text(
+        registry or CLEAN_REGISTRY,
+        encoding="utf-8",
+    )
+
+
+def _find_by_id(findings: list[dict], fid: str) -> dict | None:
+    return next((f for f in findings if f.get("id") == fid), None)
+
+
+# ===================================================================
+# GROUP A: Six drift classes detected
+# ===================================================================
+
+
+def test_a1_detects_missing_required_file(tmp_path):
+    """entrypoint-required-file-missing: no fixture at all."""
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert preview["summary"]["total_findings"] == 1
+    assert "entrypoint-required-file-missing" in preview["findings_by_class"]
+    f = preview["findings_by_class"]["entrypoint-required-file-missing"][0]
+    assert f["severity"] == "warning"
+    assert "README.md" in f["paths"]
+    assert f["authority_class"] == "canonical"
+
+
+def test_a2_detects_missing_read_order_links(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert "entrypoint-read-order-missing-links" in preview["findings_by_class"]
+    f = preview["findings_by_class"]["entrypoint-read-order-missing-links"][0]
+    assert "docs/INDEX.md" in f["evidence"]
+    assert f["paths"] == ["README.md"]
+
+
+def test_a3_detects_stale_phase4_status(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="""# LifeOS
+
+**Current Status**: Phase 4 Preparation — Tier-3 Authorized.
+
+Repo canon wins on conflict. The strategic corpus is derived.
+
+[docs/INDEX.md](docs/INDEX.md)
+[onboarding](docs/08_manuals/LifeOS_Operator_Onboarding.md)
+[state](docs/11_admin/LIFEOS_STATE.md)
+[architecture](docs/00_foundations/LifeOS%20Target%20Architecture%20v2.3c.md)
+""",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert "entrypoint-readme-status-contradicts-lifeos-state" in preview["findings_by_class"]
+    f = preview["findings_by_class"]["entrypoint-readme-status-contradicts-lifeos-state"][0]
+    assert "Phase 4" in f["evidence"] or "Tier-3" in f["evidence"]
+
+
+def test_a4_detects_missing_derived_boundary(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="""# LifeOS
+
+**Current Status**: Live COO operations.
+
+1. [docs/INDEX.md](docs/INDEX.md)
+2. [onboarding](docs/08_manuals/LifeOS_Operator_Onboarding.md)
+3. [state](docs/11_admin/LIFEOS_STATE.md)
+4. [architecture](docs/00_foundations/LifeOS%20Target%20Architecture%20v2.3c.md)
+""",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert "entrypoint-derived-surface-boundary-missing" in preview["findings_by_class"]
+    f = preview["findings_by_class"]["entrypoint-derived-surface-boundary-missing"][0]
+    assert "derived" in f["evidence"].lower()
+
+
+def test_a5_detects_index_registry_mismatch(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        registry="""doc_groups:
+  - id: wrong-root-navigation
+    authority: derived
+    paths:
+      - docs/INDEX.md
+""",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert "entrypoint-index-authority-registry-mismatch" in preview["findings_by_class"]
+    f = preview["findings_by_class"]["entrypoint-index-authority-registry-mismatch"][0]
+    assert "authority_registry" in f["evidence"] or "INDEX.md" in f["evidence"]
+
+
+def test_a6_detects_corpus_registry_mismatch(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        registry="""doc_groups:
+  - id: canonical-root-navigation
+    authority: canonical
+    paths:
+      - docs/INDEX.md
+""",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert "entrypoint-corpus-authority-registry-mismatch" in preview["findings_by_class"]
+
+
+# ===================================================================
+# GROUP B: Clean state
+# ===================================================================
+
+
+def test_b1_clean_fixture_no_findings(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert preview["summary"]["total_findings"] == 0
+    assert preview["summary"]["total_classes"] == 0
+    assert preview["findings_by_class"] == {}
+    assert preview["fingerprints"] == {}
+
+
+# ===================================================================
+# GROUP C: Fingerprint stability
+# ===================================================================
+
+
+def test_c1_fingerprint_deterministic(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview1 = build_preview(findings)
+    preview2 = build_preview(findings)
+
+    assert preview1["fingerprints"] == preview2["fingerprints"]
+
+
+def test_c2_fingerprint_differs_on_input_change(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings_a = check_entrypoint_freshness(tmp_path)
+    fp_a = build_preview(findings_a)["fingerprints"]
+
+    # Different README -> different findings -> different fingerprints
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n",
+    )
+    findings_b = check_entrypoint_freshness(tmp_path)
+    fp_b = build_preview(findings_b)["fingerprints"]
+
+    assert fp_a != fp_b
+
+
+def test_c3_fingerprint_stable_across_runs(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    for _, fp in preview["fingerprints"].items():
+        assert isinstance(fp, str)
+        assert len(fp) == 16
+        assert all(c in "0123456789abcdef" for c in fp)
+
+
+def test_c4_fingerprint_16_char_hex(tmp_path):
+    groups = _group_findings(
+        [{"id": "test-class", "evidence": "some evidence", "authority_class": "canonical"}]
+    )
+    fps = _compute_fingerprints(groups)
+    fp = fps["test-class"]
+
+    assert isinstance(fp, str)
+    assert len(fp) == 16
+    assert all(c in "0123456789abcdef" for c in fp)
+
+
+# ===================================================================
+# GROUP D: JSON shape
+# ===================================================================
+
+
+def test_d1_required_top_level_keys(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    required = {
+        "sweep_metadata",
+        "summary",
+        "findings_by_class",
+        "fingerprints",
+        "parent_link",
+        "receipt",
+    }
+    assert required.issubset(preview.keys())
+
+
+def test_d2_metadata_types(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    meta = preview["sweep_metadata"]
+
+    assert meta["sweep_id"] == SWEEP_ID
+    assert meta["target"] == TARGET
+    assert meta["check_id"] == CHECK_ID
+    assert meta["schema_version"] == SCHEMA_VERSION
+    assert isinstance(meta["generation_timestamp"], str)
+
+
+def test_d3_receipt_dry_run_true(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    receipt = preview["receipt"]
+
+    assert receipt["dry_run"] is True
+    assert receipt["mutated"] is False
+    assert receipt["tool"] == "drift_sweep_issue_creator"
+
+
+def test_d4_summary_counts_match_findings(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    summary = preview["summary"]
+
+    total = 0
+    for info in summary["classes"].values():
+        total += info["count"]
+    assert total == summary["total_findings"]
+    assert summary["total_classes"] == len(preview["findings_by_class"])
+
+
+# ===================================================================
+# GROUP E: Markdown rendering
+# ===================================================================
+
+
+def test_e1_render_with_findings(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    md = render_markdown(preview)
+
+    assert "# Advisory Documentation Drift Sweep Preview" in md
+    assert "finding(s) across" in md
+    assert "entrypoint-read-order-missing-links" in md
+    assert "No files were mutated" in md
+
+
+def test_e2_render_empty_state(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    md = render_markdown(preview)
+
+    assert "# Advisory Documentation Drift Sweep Preview" in md
+    assert "No drift findings detected" in md
+    assert "| Drift Class | Count | Fingerprint |" not in md
+    assert "finding(s) across" not in md
+
+
+def test_e3_render_with_parent_link(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings, parent_link="https://github.com/example/123")
+    md = render_markdown(preview)
+
+    assert "Parent issue" in md
+    assert "https://github.com/example/123" in md
+
+
+def test_e4_render_without_parent_link(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    md = render_markdown(preview)
+
+    assert "Parent issue" not in md
+
+
+# ===================================================================
+# GROUP F: Safe repeated runs
+# ===================================================================
+
+
+def test_f1_same_fixture_same_preview(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview1 = build_preview(findings)
+    preview2 = build_preview(findings)
+
+    assert preview1["summary"] == preview2["summary"]
+    assert preview1["fingerprints"] == preview2["fingerprints"]
+
+
+def test_f2_write_twice_no_error(tmp_path):
+    _write_entrypoint_fixture(
+        tmp_path,
+        readme="# LifeOS\n\nRepo canon wins on conflict. The strategic corpus is derived.\n",
+    )
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+    out = tmp_path / "out"
+
+    write_preview(preview, out)  # first write
+    write_preview(preview, out)  # second write — no error
+
+
+# ===================================================================
+# GROUP G: Output directory
+# ===================================================================
+
+
+def test_g1_output_dir_auto_created(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    out = tmp_path / "nonexistent" / "subdir"
+    write_preview(preview, out)
+
+    assert out.is_dir()
+
+
+def test_g2_json_and_md_files_written(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    out = tmp_path / "out"
+    files = write_preview(preview, out)
+
+    for f in files:
+        assert f.exists(), f"Expected {f} to exist"
+    assert any(f.suffix == ".json" for f in files)
+    assert any(f.suffix == ".md" for f in files)
+
+
+def test_g3_latest_files_written(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    out = tmp_path / "out"
+    write_preview(preview, out)
+
+    assert (out / "drift_sweep_preview_latest.json").exists()
+    assert (out / "drift_sweep_preview_latest.md").exists()
+
+
+def test_g4_custom_output_dir(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    custom = tmp_path / "custom_output"
+    write_preview(preview, custom)
+
+    files = list(custom.iterdir())
+    assert len(files) >= 4  # timestamped json+md + latest json+md
+
+
+# ===================================================================
+# GROUP H: Parent link
+# ===================================================================
+
+
+def test_h1_parent_link_in_json_when_set(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings, parent_link="https://github.com/example/456")
+
+    assert preview["parent_link"] == "https://github.com/example/456"
+
+
+def test_h2_parent_link_none_when_omitted(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    findings = check_entrypoint_freshness(tmp_path)
+    preview = build_preview(findings)
+
+    assert preview["parent_link"] is None
+
+
+# ===================================================================
+# GROUP I: CLI integration
+# ===================================================================
+
+
+def test_i1_main_exit_zero(tmp_path):
+    _write_entrypoint_fixture(tmp_path)
+    rc = main([str(tmp_path)])
+    assert rc == 0
+
+
+def test_i2_main_exit_zero_with_findings(tmp_path):
+    # No fixture -> required file missing -> findings present
+    rc = main([str(tmp_path)])
+    assert rc == 0
+
+
+# ===================================================================
+# Internal helpers unit tests
+# ===================================================================
+
+
+def test_normalize_evidence_stable_order():
+    findings = [
+        {"id": "b-class", "evidence": "ZZZ"},
+        {"id": "a-class", "evidence": "AAA"},
+    ]
+    result = _normalize_evidence(findings)
+    assert result == "aaa | zzz"
+
+
+def test_group_findings_preserves_order():
+    findings = [
+        {"id": "z-first", "evidence": "z"},
+        {"id": "a-second", "evidence": "a"},
+        {"id": "z-first", "evidence": "z again"},
+    ]
+    groups = _group_findings(findings)
+    keys = list(groups.keys())
+    assert keys == ["z-first", "a-second"]
+    assert len(groups["z-first"]) == 2