diff --git a/scripts/publish-pack.py b/scripts/publish-pack.py
new file mode 100644
index 0000000..f5757ad
--- /dev/null
+++ b/scripts/publish-pack.py
@@ -0,0 +1,169 @@
+#!/usr/bin/env python3
+"""
+Linux-side port of Build-Pack.ps1 + Deploy-Brass.ps1 (publish step).
+
+Reads pack/pack.lock.json + walks pack/overrides/, rebuilds manifest.json,
+mirrors every override file to the live web root, and republishes the
+manifest. The launcher will then see fresh hashes on its next sync.
+
+Run on glados with passwordless sudo. Idempotent.
+
+Web root: /srv/services/sites/bns (mounted into Caddy as /srv/sites/bns).
+"""
+import hashlib
+import json
+import shutil
+import subprocess
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+
+REPO = Path("/home/matt/dev/brass-and-sigil")
+LOCK_PATH = REPO / "pack" / "pack.lock.json"
+OVERRIDES = REPO / "pack" / "overrides"
+WEB_ROOT = Path("/srv/services/sites/bns/pack")
+WEB_FILES = WEB_ROOT / "files"
+WEB_MANIFEST = WEB_ROOT / "manifest.json"
+SELF_HOST_BASE = "https://bns.sijbers.uk/pack/files"
+
+MANAGED_ROOTS = ["mods", "config", "resourcepacks", "shaderpacks", "kubejs", "defaultconfigs", "patchouli_books"]
+
+# bnstoolkit ships client+server surface (screens, HUD, network bridge),
+# so it must NOT inherit the default "server-only" tag that Build-Pack.ps1
+# stamps on every pack/overrides/mods/*.jar. brassandsigil_tweaks is
+# data-only (worldgen modifiers / recipe overrides) so server-side is
+# correct for it.
+CLIENT_AND_SERVER_LOCAL_MODS = {"bnstoolkit"}
+
+
+def sha1_of(p: Path) -> str:
+    h = hashlib.sha1()
+    with p.open("rb") as f:
+        for chunk in iter(lambda: f.read(1 << 16), b""):
+            h.update(chunk)
+    return h.hexdigest()
+
+
+def main():
+    with LOCK_PATH.open() as f:
+        lock = json.load(f)
+
+    files = []
+    total_bytes = 0
+
+    # 1. Mods from the lockfile (Modrinth-hosted)
+    for m in lock["mods"]:
+        entry = {
+            "path": m["path"],
+            "url":  m["url"],
+            "sha1": m["sha1"],
+            "size": m["size"],
+        }
+        side = m.get("side")
+        if side and side != "both":
+            entry["side"] = side
+        files.append(entry)
+        total_bytes += m["size"]
+
+    # 2. Local overrides
+    for root in MANAGED_ROOTS:
+        root_dir = OVERRIDES / root
+        if not root_dir.exists():
+            continue
+        for p in sorted(root_dir.rglob("*")):
+            if not p.is_file():
+                continue
+            rel = p.relative_to(OVERRIDES).as_posix()
+            sha1 = sha1_of(p)
+            size = p.stat().st_size
+            entry = {
+                "path": rel,
+                "url":  f"{SELF_HOST_BASE}/{rel}",
+                "sha1": sha1,
+                "size": size,
+            }
+            if root == "mods":
+                # See CLIENT_AND_SERVER_LOCAL_MODS — bnstoolkit must be loaded
+                # on both sides; the other locally-built mods are server-only.
+                stem = p.name.split("-")[0].split("_")[0]  # before first - or _
+                if not any(p.name.startswith(prefix) for prefix in CLIENT_AND_SERVER_LOCAL_MODS):
+                    entry["side"] = "server"
+            files.append(entry)
+            total_bytes += size
+
+    # 3. Compose manifest matching the existing schema
+    manifest = {
+        "name":      lock["name"],
+        "version":   lock["version"],
+        "minecraft": {"version": lock["minecraft"]},
+        "loader":    {"type": lock["loader"]["type"], "version": lock["loader"]["version"]},
+        "files":     files,
+    }
+    for opt in ("defaultServer", "defaultShader", "panelUrl"):
+        if opt in lock:
+            manifest[opt] = lock[opt]
+
+    # Carry the launcher metadata from the existing published manifest
+    # (we can't read a Windows .exe's FileVersion from Linux easily, and
+    # the launcher version isn't related to pack content).
+    try:
+        with WEB_MANIFEST.open() as f:
+            existing = json.load(f)
+        for k in ("launcherVersion", "launcherUrl"):
+            if k in existing:
+                manifest[k] = existing[k]
+    except Exception:
+        pass
+
+    # 4. Mirror override files to web root (uses sudo + cp -a). Only update
+    # files whose hash differs from what's already published to keep the
+    # rsync footprint tiny.
+    print(f"\nMirroring {sum(1 for r in MANAGED_ROOTS if (OVERRIDES / r).exists())} override roots to {WEB_FILES}\n")
+    changed = 0
+    skipped = 0
+    for root in MANAGED_ROOTS:
+        root_dir = OVERRIDES / root
+        if not root_dir.exists():
+            continue
+        target_root = WEB_FILES / root
+        for p in root_dir.rglob("*"):
+            if not p.is_file():
+                continue
+            rel = p.relative_to(OVERRIDES)
+            target = WEB_FILES / rel
+            try:
+                if target.exists() and sha1_of(target) == sha1_of(p):
+                    skipped += 1
+                    continue
+            except PermissionError:
+                # Need sudo to read
+                pass
+            target.parent.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(p, target)
+            changed += 1
+    print(f"  changed: {changed}, skipped (matching hash): {skipped}\n")
+
+    # 5. Write the manifest atomically (write to .new, then move)
+    new_manifest = WEB_MANIFEST.with_suffix(".json.new")
+    bak_manifest = WEB_MANIFEST.with_suffix(".json.bak")
+    if WEB_MANIFEST.exists():
+        shutil.copy2(WEB_MANIFEST, bak_manifest)
+    with new_manifest.open("w") as f:
+        json.dump(manifest, f, indent=2, ensure_ascii=False)
+        f.write("\n")
+    new_manifest.replace(WEB_MANIFEST)
+
+    print(f"Manifest written: {WEB_MANIFEST}")
+    print(f"  Version:  {lock['version']}")
+    print(f"  Files:    {len(files)}")
+    print(f"  Total:    {total_bytes / 1024 / 1024:.1f} MB download")
+    print()
+    # Quick verify
+    rel = "kubejs/server_scripts/economy/00_tier_system.js"
+    entry = next((f for f in files if f["path"] == rel), None)
+    if entry:
+        print(f"  {rel} -> sha1={entry['sha1'][:12]}... size={entry['size']}")
+
+
+if __name__ == "__main__":
+    main()