diff --git a/.github/workflows/integrity.yml b/.github/workflows/integrity.yml
new file mode 100644
index 0000000..be90e64
--- /dev/null
+++ b/.github/workflows/integrity.yml
@@ -0,0 +1,19 @@
+name: Integrity
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  checksum-domain:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+      - name: Verify declared checksum byte domains
+        run: python3 tools/verify_checksum_domain.py
diff --git a/CHECKSUM_DOMAIN.json b/CHECKSUM_DOMAIN.json
new file mode 100644
index 0000000..5987f6e
--- /dev/null
+++ b/CHECKSUM_DOMAIN.json
@@ -0,0 +1,49 @@
+{
+  "schema_version": "checksum-domain.v1",
+  "document_id": "world-intelligence-v1.1.0-checksum-domain",
+  "last_verified": "2026-08-07",
+  "repository": "https://github.com/Kot141078/world-intelligence",
+  "observed_head_commit": "069c995703ef1648f06e1363fb37491835ed363e",
+  "scope": "Interpretation layer for repository-layout manifests; release-asset and metadata-only manifests remain raw-byte domains.",
+  "authority_rule": "The two repository-layout manifests recorded CRLF representations of .gitattributes and .gitignore. Current Git blobs and checkout policy use LF. This declaration makes that byte-domain conversion explicit without altering publication or release bytes.",
+  "claim_boundary": "A checksum match establishes byte identity in the declared hash domain only; it does not establish authorship beyond cited metadata, completeness, translation quality, scientific validity, safety, or deployment status.",
+  "manifests": [
+    {
+      "path": "hashes/SHA256SUMS.repo-all.txt",
+      "hash_algorithm": "sha256",
+      "default_mode": "raw_bytes",
+      "path_modes": {
+        "crlf_text_bytes": [
+          ".gitattributes",
+          ".gitignore"
+        ]
+      },
+      "expected_entries": 43
+    },
+    {
+      "path": "hashes/SHA256SUMS.repo-layout.txt",
+      "hash_algorithm": "sha256",
+      "default_mode": "raw_bytes",
+      "path_modes": {
+        "crlf_text_bytes": [
+          ".gitattributes",
+          ".gitignore"
+        ]
+      },
+      "expected_entries": 39
+    },
+    {
+      "path": "hashes/SHA256SUMS.metadata-only.txt",
+      "hash_algorithm": "sha256",
+      "default_mode": "raw_bytes",
+      "path_modes": {
+        "crlf_text_bytes": []
+      },
+      "expected_entries": 10
+    }
+  ],
+  "verification": {
+    "command": "python3 tools/verify_checksum_domain.py",
+    "normalization_rule": "For crlf_text_bytes only, an LF checkout is transformed to CRLF before hashing. Existing CRLF bytes are hashed unchanged; mixed or bare-CR input is rejected."
+  }
+}
diff --git a/tools/verify_checksum_domain.py b/tools/verify_checksum_domain.py
new file mode 100644
index 0000000..16cbec9
--- /dev/null
+++ b/tools/verify_checksum_domain.py
@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+import hashlib
+import json
+import re
+import sys
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parent.parent
+CONFIG_PATH = ROOT / "CHECKSUM_DOMAIN.json"
+SHA256_RE = re.compile(r"^[0-9a-fA-F]{64}$")
+
+
+def fail(message: str) -> None:
+    raise ValueError(message)
+
+
+def safe_file(relative: str) -> Path:
+    path = Path(relative)
+    if path.is_absolute() or ".." in path.parts:
+        fail(f"Unsafe manifest path: {relative!r}")
+    resolved = (ROOT / path).resolve()
+    if ROOT.resolve() not in resolved.parents:
+        fail(f"Manifest path escapes repository: {relative!r}")
+    return resolved
+
+
+def crlf_bytes(data: bytes, relative: str) -> bytes:
+    if b"\r\n" in data:
+        if data.replace(b"\r\n", b"").find(b"\r") >= 0:
+            fail(f"Mixed or bare-CR text is not admissible: {relative}")
+        return data
+    if b"\r" in data:
+        fail(f"Bare-CR text is not admissible: {relative}")
+    return data.replace(b"\n", b"\r\n")
+
+
+def manifest_entries(path: Path) -> list[tuple[str, str]]:
+    entries: list[tuple[str, str]] = []
+    seen: set[str] = set()
+    for line_number, line in enumerate(path.read_text(encoding="utf-8-sig").splitlines(), start=1):
+        if not line.strip() or line.lstrip().startswith("#"):
+            continue
+        parts = line.split(None, 1)
+        if len(parts) != 2 or not SHA256_RE.fullmatch(parts[0]):
+            fail(f"Malformed checksum line {path.relative_to(ROOT)}:{line_number}")
+        relative = parts[1].lstrip("*").strip()
+        if relative in seen:
+            fail(f"Duplicate checksum path in {path.relative_to(ROOT)}: {relative}")
+        seen.add(relative)
+        entries.append((parts[0].lower(), relative))
+    return entries
+
+
+def main() -> int:
+    try:
+        config = json.loads(CONFIG_PATH.read_text(encoding="utf-8"))
+        if config.get("schema_version") != "checksum-domain.v1":
+            fail("Unsupported checksum-domain schema_version")
+        checked = 0
+        for declaration in config["manifests"]:
+            manifest_path = safe_file(declaration["path"])
+            entries = manifest_entries(manifest_path)
+            if len(entries) != declaration["expected_entries"]:
+                fail(f"Entry count mismatch for {declaration['path']}")
+            crlf_paths = set(declaration["path_modes"].get("crlf_text_bytes", []))
+            entry_paths = {relative for _, relative in entries}
+            if not crlf_paths <= entry_paths:
+                fail(f"Declared CRLF path is absent from {declaration['path']}")
+            for expected, relative in entries:
+                data = safe_file(relative).read_bytes()
+                if relative in crlf_paths:
+                    data = crlf_bytes(data, relative)
+                actual = hashlib.sha256(data).hexdigest()
+                if actual != expected:
+                    fail(f"Checksum mismatch in {declaration['path']}: {relative}")
+                checked += 1
+        print(f"PASS checksum-domain.v1: {checked} manifest entries")
+        return 0
+    except (OSError, KeyError, TypeError, json.JSONDecodeError, ValueError) as exc:
+        print(f"FAIL {exc}", file=sys.stderr)
+        return 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())