diff --git a/ai/hermes/Dockerfile b/ai/hermes/Dockerfile
index a6edcfc..caa966a 100644
--- a/ai/hermes/Dockerfile
+++ b/ai/hermes/Dockerfile
@@ -79,6 +79,39 @@ PYEOF
 COPY --chmod=0755 himalaya-ro.sh /usr/local/bin/himalaya-ro
 
 
+# ---------- Install 7-Zip (7zz) for CHM extraction ----------
+RUN /opt/hermes/.venv/bin/python3 /dev/stdin << 'PYEOF'
+import urllib.request, tarfile, os, shutil, re, subprocess
+
+# Scrape 7-zip.org for latest Linux x64 binary link
+url = 'https://7-zip.org/download.html'
+req = urllib.request.Request(url, headers={'User-Agent': 'Mozilla/5.0'})
+r = urllib.request.urlopen(req, timeout=15)
+html = r.read().decode()
+match = re.search(r'href="(a/7z[\d]+-linux-x64\.tar\.xz)"', html)
+if not match:
+    raise RuntimeError('Could not find 7z Linux x64 download link on 7-zip.org')
+dl_url = f'https://7-zip.org/{match.group(1)}'
+
+# Follow Himalaya pattern: download, extract, install, verify
+xz = '/tmp/7z.tar.xz'
+urllib.request.urlretrieve(dl_url, xz)
+os.makedirs('/tmp/7z', exist_ok=True)
+with tarfile.open(xz, 'r:xz') as t:
+    t.extractall('/tmp/7z')
+shutil.move('/tmp/7z/7zz', '/usr/local/bin/7zz')
+os.chmod('/usr/local/bin/7zz', 0o755)
+shutil.rmtree('/tmp/7z', ignore_errors=True)
+os.remove(xz)
+
+# Verify
+result = subprocess.run(['/usr/local/bin/7zz'], capture_output=True, text=True)
+assert result.returncode == 0, f'7zz verify failed: {result.stderr}'
+version = result.stdout.split()[2] if result.stdout else 'unknown'
+print(f'7-Zip {version} installed successfully')
+PYEOF
+
+
 # ---------- Runtime ----------
 USER hermes
 ENV HERMES_HOME=/opt/data