refactor: split compat into package, harden serve proxy (v0.9.3)

- compat.py → compat/ package: auth.py (auth-field normalizers),
  commands.py (command-format shims), __init__.py (re-exports)
- Add _auth_0_9_3 transformer: normalizes pubkey to lowercase before auth
  so clients < 0.9.3 sending uppercase hex are accepted
- adapt_auth() now called before auth check in serve.py; command extracted
  after adapt_auth so future transformers can rename commands safely
- serve.py: deduplicate _recv_exact (import from client), unify
  resp/resp_payload across Windows/Unix branches, require lowercase hex
  pubkey (re.fullmatch), reorganize imports, drop unused os import
- client.py: move payload/framed construction inside branches (remote path
  no longer serializes JSON it never uses); fix _is_valid_key_spec
  operator precedence; import MAX_MSG_BYTES from version_manager
- auth.py: narrow except clause (ValueError instead of bare Exception)
- Bump version 0.9.2 → 0.9.3

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_auth.py

@@ -0,0 +1,160 @@
+import json
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from browser_cli.auth import (
+    add_authorized_key,
+    canonical_payload,
+    generate_keypair,
+    load_authorized_keys,
+    load_authorized_keys_with_names,
+    load_private_key,
+    new_nonce,
+    sign,
+    verify,
+)
+from browser_cli.client import _is_valid_key_spec
+
+
+class TestGenerateKeypair:
+    def test_returns_pem_and_hex(self):
+        pem, pub_hex = generate_keypair()
+        assert pem.startswith(b"-----BEGIN PRIVATE KEY-----")
+        assert len(pub_hex) == 64
+
+    def test_each_call_unique(self):
+        _, pub1 = generate_keypair()
+        _, pub2 = generate_keypair()
+        assert pub1 != pub2
+
+
+class TestCanonicalPayload:
+    def test_strips_pubkey_and_sig(self):
+        msg = {"command": "tabs.list", "id": "x", "pubkey": "abc", "sig": "def"}
+        data = json.loads(canonical_payload(msg))
+        assert "pubkey" not in data
+        assert "sig" not in data
+
+    def test_keys_sorted(self):
+        msg = {"z": 1, "a": 2, "m": 3}
+        payload = canonical_payload(msg).decode()
+        assert payload.index('"a"') < payload.index('"m"') < payload.index('"z"')
+
+    def test_deterministic(self):
+        msg = {"b": 2, "a": 1}
+        assert canonical_payload(msg) == canonical_payload(msg)
+
+
+@pytest.fixture()
+def keypair(tmp_path):
+    pem, pub_hex = generate_keypair()
+    key_path = tmp_path / "client.key.pem"
+    key_path.write_bytes(pem)
+    priv = load_private_key(key_path)
+    return priv, pub_hex
+
+
+class TestSignVerify:
+    def test_valid_signature_verifies(self, keypair):
+        priv, pub_hex = keypair
+        nonce = bytes.fromhex(new_nonce())
+        msg = {"command": "tabs.list", "id": "uuid-1", "args": {}}
+        sig = sign(priv, nonce, msg).hex()
+        assert verify(pub_hex, nonce, msg, sig) is True
+
+    def test_tampered_sig_fails(self, keypair):
+        priv, pub_hex = keypair
+        nonce = bytes.fromhex(new_nonce())
+        msg = {"command": "tabs.list", "id": "x"}
+        sign(priv, nonce, msg)
+        assert verify(pub_hex, nonce, msg, "00" * 64) is False
+
+    def test_wrong_pubkey_fails(self, keypair):
+        priv, _ = keypair
+        _, other_pub = generate_keypair()
+        nonce = bytes.fromhex(new_nonce())
+        msg = {"command": "tabs.list"}
+        sig = sign(priv, nonce, msg).hex()
+        assert verify(other_pub, nonce, msg, sig) is False
+
+    def test_wrong_nonce_fails(self, keypair):
+        priv, pub_hex = keypair
+        nonce = bytes.fromhex(new_nonce())
+        msg = {"command": "tabs.list"}
+        sig = sign(priv, nonce, msg).hex()
+        other_nonce = bytes.fromhex(new_nonce())
+        assert verify(pub_hex, other_nonce, msg, sig) is False
+
+    def test_garbage_pub_hex_returns_false_not_exception(self):
+        assert verify("not-hex!!!!", b"nonce", {}, "00" * 64) is False
+
+    def test_truncated_sig_hex_returns_false_not_exception(self, keypair):
+        _, pub_hex = keypair
+        assert verify(pub_hex, b"nonce", {}, "aabb") is False
+
+    def test_wrong_length_pubkey_returns_false_not_exception(self):
+        assert verify("aabbcc", b"nonce", {}, "00" * 64) is False
+
+
+class TestAuthorizedKeys:
+    def test_add_and_load(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        _, pub = generate_keypair()
+        assert add_authorized_key(path, pub, "alice") is True
+        assert pub in load_authorized_keys(path)
+
+    def test_add_duplicate_returns_false(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        _, pub = generate_keypair()
+        add_authorized_key(path, pub)
+        assert add_authorized_key(path, pub) is False
+
+    def test_load_with_names(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        _, pub1 = generate_keypair()
+        _, pub2 = generate_keypair()
+        add_authorized_key(path, pub1, "alice")
+        add_authorized_key(path, pub2)
+        entries = load_authorized_keys_with_names(path)
+        assert (pub1, "alice") in entries
+        assert (pub2, "") in entries
+
+    def test_ignores_comment_lines(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        path.write_text("# this is a comment\n")
+        assert load_authorized_keys(path) == []
+
+    def test_returns_empty_for_missing_file(self, tmp_path):
+        assert load_authorized_keys(tmp_path / "nofile") == []
+
+
+class TestIsValidKeySpec:
+    def test_agent_bare(self):
+        assert _is_valid_key_spec("agent") is True
+
+    def test_agent_with_selector(self):
+        assert _is_valid_key_spec("agent:cardno:000012345678") is True
+
+    def test_absolute_pem_path(self):
+        assert _is_valid_key_spec("/home/user/.config/browser-cli/client.key.pem") is True
+
+    def test_dot_key_extension(self):
+        assert _is_valid_key_spec("/tmp/mykey.key") is True
+
+    def test_angled_bracket_pem_rejected(self):
+        # regression: operator precedence bug allowed "<garbage>.pem" to pass
+        assert _is_valid_key_spec("<garbage>.pem") is False
+
+    def test_angled_bracket_key_rejected(self):
+        assert _is_valid_key_spec("<garbage>.key") is False
+
+    def test_serialized_object_rejected(self):
+        assert _is_valid_key_spec("<AgentKey(blob=b'...', comment='test')>.pem") is False
+
+    def test_empty_string_rejected(self):
+        assert _is_valid_key_spec("") is False
+
+    def test_bare_filename_no_slash_no_ext_rejected(self):
+        assert _is_valid_key_spec("mykey") is False

tests/test_cli.py

@@ -262,12 +262,12 @@ def test_tabs_list_multi_browser_shows_browser_column():
         return [{"id": 1 if profile == "default" else 2, "windowId": 1, "active": True, "title": profile, "url": "https://example.com"}]
 
     with patch(
-        "browser_cli.commands.tabs.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "550e8400-e29b-41d4-a716-446655440000", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
-    ), patch("browser_cli.commands.tabs.send_command", side_effect=fake_send_command):
+    ), patch("browser_cli.commands.send_command", side_effect=fake_send_command):
         result = CliRunner().invoke(main, ["tabs", "list"])
 
     assert result.exit_code == 0
@@ -278,13 +278,13 @@ def test_tabs_list_multi_browser_shows_browser_column():
 
 def test_tabs_list_with_remote_uses_only_remote_targets():
     with patch(
-        "browser_cli.commands.tabs.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         side_effect=AssertionError("local targets should not be used for explicit remote"),
     ), patch(
-        "browser_cli.commands.tabs.remote_browser_targets",
+        "browser_cli.commands.remote_browser_targets",
         return_value=[BrowserTarget("work", "remote-host:work", "", remote="remote-host:8765")],
     ), patch(
-        "browser_cli.commands.tabs.send_command",
+        "browser_cli.commands.send_command",
         return_value=[{"id": 1, "windowId": 1, "active": True, "title": "Remote", "url": "https://example.com"}],
     ) as send_command:
         result = CliRunner().invoke(main, ["--remote", "remote-host:8765", "tabs", "list"])
@@ -297,13 +297,13 @@ def test_tabs_list_with_remote_uses_only_remote_targets():
 
 def test_tabs_list_with_explicit_browser_does_not_show_browser_column():
     with patch(
-        "browser_cli.commands.tabs.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "uuid-1", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
     ), patch(
-        "browser_cli.commands.tabs.send_command",
+        "browser_cli.commands.send_command",
         return_value=[{"id": 1, "windowId": 1, "active": True, "title": "Example", "url": "https://example.com"}],
     ) as send_command:
         result = CliRunner().invoke(main, ["--browser", "work", "tabs", "list"])
@@ -322,12 +322,12 @@ def test_tabs_count_multi_browser_shows_total():
         return counts[profile]
 
     with patch(
-        "browser_cli.commands.tabs.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "uuid-1", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
-    ), patch("browser_cli.commands.tabs.send_command", side_effect=fake_send_command):
+    ), patch("browser_cli.commands.send_command", side_effect=fake_send_command):
         result = CliRunner().invoke(main, ["tabs", "count", "github"])
 
     assert result.exit_code == 0
@@ -344,12 +344,12 @@ def test_group_count_multi_browser_shows_total():
         return counts[profile]
 
     with patch(
-        "browser_cli.commands.groups.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "uuid-1", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
-    ), patch("browser_cli.commands.groups.send_command", side_effect=fake_send_command):
+    ), patch("browser_cli.commands.send_command", side_effect=fake_send_command):
         result = CliRunner().invoke(main, ["groups", "count"])
 
     assert result.exit_code == 0
@@ -360,7 +360,7 @@ def test_group_count_multi_browser_shows_total():
 
 def test_group_list_leaves_unnamed_group_cell_empty():
     with patch(
-        "browser_cli.commands.groups.send_command",
+        "browser_cli.commands.send_command",
         return_value=[{"id": 42, "title": "", "color": "grey", "collapsed": False, "tabCount": 1}],
     ):
         result = CliRunner().invoke(main, ["groups", "list"])
@@ -372,7 +372,7 @@ def test_group_list_leaves_unnamed_group_cell_empty():
 
 
 def test_tabs_move_accepts_right_short_alias():
-    with patch("browser_cli.commands.tabs.send_command") as send_command:
+    with patch("browser_cli.commands.send_command") as send_command:
         result = CliRunner().invoke(main, ["tabs", "move", "12", "-r"])
 
     assert result.exit_code == 0
@@ -384,7 +384,7 @@ def test_tabs_move_accepts_right_short_alias():
 
 
 def test_groups_move_accepts_left_short_alias():
-    with patch("browser_cli.commands.groups.send_command") as send_command:
+    with patch("browser_cli.commands.send_command") as send_command:
         result = CliRunner().invoke(main, ["groups", "move", "research", "-l"])
 
     assert result.exit_code == 0
@@ -399,12 +399,12 @@ def test_windows_list_multi_browser_shows_browser_column():
         return [{"id": 1, "alias": profile, "focused": True, "tabCount": 2, "state": "normal"}]
 
     with patch(
-        "browser_cli.commands.windows.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "uuid-1", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
-    ), patch("browser_cli.commands.windows.send_command", side_effect=fake_send_command):
+    ), patch("browser_cli.commands.send_command", side_effect=fake_send_command):
         result = CliRunner().invoke(main, ["windows", "list"])
 
     assert result.exit_code == 0
@@ -420,12 +420,12 @@ def test_session_list_multi_browser_shows_browser_column():
         return [{"name": f"{profile}-session", "tabs": 2, "savedAt": 1712707200000}]
 
     with patch(
-        "browser_cli.commands.session.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "uuid-1", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
-    ), patch("browser_cli.commands.session.send_command", side_effect=fake_send_command):
+    ), patch("browser_cli.commands.send_command", side_effect=fake_send_command):
         result = CliRunner().invoke(main, ["session", "list"])
 
     assert result.exit_code == 0
@@ -438,13 +438,13 @@ def test_session_list_multi_browser_shows_browser_column():
 
 def test_session_list_with_explicit_browser_does_not_show_browser_column():
     with patch(
-        "browser_cli.commands.session.active_browser_targets",
+        "browser_cli.commands.active_browser_targets",
         return_value=[
             BrowserTarget("default", "uuid-1", "/tmp/default.sock"),
             BrowserTarget("work", "work", "/tmp/work.sock"),
         ],
     ), patch(
-        "browser_cli.commands.session.send_command",
+        "browser_cli.commands.send_command",
         return_value=[{"name": "work-session", "tabs": 2, "savedAt": 1712707200000}],
     ) as send_command:
         result = CliRunner().invoke(main, ["--browser", "work", "session", "list"])
@@ -455,7 +455,7 @@ def test_session_list_with_explicit_browser_does_not_show_browser_column():
 
 
 def test_windows_open_passes_url():
-    with patch("browser_cli.commands.windows.send_command", return_value={"id": 7}) as send_command:
+    with patch("browser_cli.commands.send_command", return_value={"id": 7}) as send_command:
         result = CliRunner().invoke(main, ["windows", "open", "https://example.com"])
 
     assert result.exit_code == 0
@@ -463,20 +463,20 @@ def test_windows_open_passes_url():
     send_command.assert_called_once_with("windows.open", {"url": "https://example.com"}, profile=None)
 
 def test_extract_markdown_command():
-    with patch("browser_cli.commands.extract.send_command", return_value="# Title") as send_command:
+    with patch("browser_cli.commands.send_command", return_value="# Title") as send_command:
         result = CliRunner().invoke(main, ["extract", "markdown"])
 
     assert result.exit_code == 0
     assert result.output == "# Title\n"
-    send_command.assert_called_once_with("extract.markdown", {"selector": None})
+    send_command.assert_called_once_with("extract.markdown", {"selector": None}, profile=None)
 
 def test_extract_markdown_command_with_selector():
-    with patch("browser_cli.commands.extract.send_command", return_value="## Post") as send_command:
+    with patch("browser_cli.commands.send_command", return_value="## Post") as send_command:
         result = CliRunner().invoke(main, ["extract", "markdown", "--selector", "article"])
 
     assert result.exit_code == 0
     assert result.output == "## Post\n"
-    send_command.assert_called_once_with("extract.markdown", {"selector": "article"})
+    send_command.assert_called_once_with("extract.markdown", {"selector": "article"}, profile=None)
 
 
 def test_clean_markdown_output_removes_escaped_underscores_and_dashes():
@@ -561,7 +561,7 @@ def test_extract_markdown_command_repairs_malformed_tables_and_code_blocks():
         "Golden Set   │   ▼Promptfoo(Testausführung)   │   ▼Plattformen├ Omnifact└ Le Chat\n"
         "```"
     )
-    with patch("browser_cli.commands.extract.send_command", return_value=raw):
+    with patch("browser_cli.commands.send_command", return_value=raw):
         result = CliRunner().invoke(main, ["extract", "markdown"])
 
     assert result.exit_code == 0
@@ -639,8 +639,8 @@ def test_tabs_list_multi_browser_queries_remote_target():
         remote=endpoint,
     )
 
-    with patch("browser_cli.commands.tabs.active_browser_targets", return_value=[remote_target, BrowserTarget("local", "local", "/tmp/local.sock")]), patch(
-        "browser_cli.commands.tabs.send_command",
+    with patch("browser_cli.commands.active_browser_targets", return_value=[remote_target, BrowserTarget("local", "local", "/tmp/local.sock")]), patch(
+        "browser_cli.commands.send_command",
         return_value=[{"id": 1, "windowId": 1, "active": True, "title": "Remote", "url": "https://example.com"}],
     ) as send_command:
         result = CliRunner().invoke(main, ["tabs", "list"])

tests/test_serve.py

@@ -0,0 +1,249 @@
+"""Unit tests for the TCP serve layer (challenge-response auth, framing, rejection paths)."""
+import json
+import socket
+import struct
+import threading
+
+import pytest
+
+from browser_cli.auth import generate_keypair, load_private_key, new_nonce, sign
+from browser_cli.client import BrowserNotConnected
+from browser_cli.commands.serve import _handle_client
+
+FAKE_UA = "browser-cli/0.9.3"
+
+
+# ── helpers ────────────────────────────────────────────────────────────────────
+
+def _send_framed(sock: socket.socket, data: bytes) -> None:
+    sock.sendall(struct.pack("<I", len(data)) + data)
+
+
+def _recv_framed(sock: socket.socket) -> dict:
+    raw = b""
+    while len(raw) < 4:
+        chunk = sock.recv(4 - len(raw))
+        if not chunk:
+            raise ConnectionError("socket closed before response header")
+        raw += chunk
+    n = struct.unpack("<I", raw)[0]
+    data = b""
+    while len(data) < n:
+        chunk = sock.recv(n - len(data))
+        if not chunk:
+            raise ConnectionError("socket closed mid-response")
+        data += chunk
+    return json.loads(data)
+
+
+def _spawn(server_sock: socket.socket, auth_keys_path) -> threading.Thread:
+    t = threading.Thread(
+        target=_handle_client,
+        args=(server_sock, ("127.0.0.1", 9999), None, auth_keys_path),
+        daemon=True,
+    )
+    t.start()
+    return t
+
+
+def _pair():
+    return socket.socketpair()
+
+
+def _mock_no_browser(*_args, **_kwargs):
+    raise BrowserNotConnected("no browser")
+
+
+# ── challenge frame ────────────────────────────────────────────────────────────
+
+class TestChallenge:
+    def test_challenge_sent_on_connect(self):
+        client, server = _pair()
+        t = _spawn(server, None)
+        challenge = _recv_framed(client)
+        assert challenge["type"] == "challenge"
+        assert "nonce" in challenge
+        client.close()
+        t.join(timeout=2)
+
+    def test_challenge_includes_version_fields(self):
+        client, server = _pair()
+        t = _spawn(server, None)
+        challenge = _recv_framed(client)
+        assert "server_version" in challenge
+        assert "min_client_version" in challenge
+        client.close()
+        t.join(timeout=2)
+
+
+# ── rejection paths ────────────────────────────────────────────────────────────
+
+class TestRejection:
+    def _connect(self, auth_keys_path):
+        client, server = _pair()
+        t = _spawn(server, auth_keys_path)
+        challenge = _recv_framed(client)
+        return client, t, challenge
+
+    def test_bad_user_agent_rejected(self):
+        client, t, _ = self._connect(None)
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": "curl/7.88"}
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+        assert resp["success"] is False
+        assert "forbidden" in resp["error"].lower() or "client" in resp["error"].lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_missing_pubkey_sig_rejected(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        _, pub = generate_keypair()
+        path.write_text(pub + "\n")
+        client, t, _ = self._connect(path)
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": FAKE_UA}
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+        assert resp["success"] is False
+        assert "unauthorized" in resp["error"].lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_untrusted_pubkey_rejected(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        _, trusted_pub = generate_keypair()
+        path.write_text(trusted_pub + "\n")
+
+        pem, untrusted_pub = generate_keypair()
+        key_path = tmp_path / "other.pem"
+        key_path.write_bytes(pem)
+        priv = load_private_key(key_path)
+
+        client, t, challenge = self._connect(path)
+        nonce = bytes.fromhex(challenge["nonce"])
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": FAKE_UA, "pubkey": untrusted_pub}
+        msg["sig"] = sign(priv, nonce, msg).hex()
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+        assert resp["success"] is False
+        assert "untrusted" in resp["error"].lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_bad_signature_rejected(self, tmp_path):
+        path = tmp_path / "authorized_keys"
+        _, pub = generate_keypair()
+        path.write_text(pub + "\n")
+        client, t, _ = self._connect(path)
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": FAKE_UA, "pubkey": pub, "sig": "00" * 64}
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+        assert resp["success"] is False
+        assert "signature" in resp["error"].lower() or "invalid" in resp["error"].lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_oversized_message_rejected(self):
+        client, server = _pair()
+        t = _spawn(server, None)
+        _recv_framed(client)  # consume challenge
+        client.sendall(struct.pack("<I", 33 * 1024 * 1024))
+        resp = _recv_framed(client)
+        assert resp["success"] is False
+        assert "too large" in resp["error"].lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_invalid_json_rejected(self):
+        client, server = _pair()
+        t = _spawn(server, None)
+        _recv_framed(client)  # consume challenge
+        bad = b"this is not json {"
+        _send_framed(client, bad)
+        resp = _recv_framed(client)
+        assert resp["success"] is False
+        client.close()
+        t.join(timeout=2)
+
+
+# ── auth success paths ─────────────────────────────────────────────────────────
+
+class TestAuthSuccess:
+    def test_valid_auth_reaches_proxy(self, tmp_path, monkeypatch):
+        """Correct signature → error must be 'browser not connected', not 'unauthorized'."""
+        path = tmp_path / "authorized_keys"
+        pem, pub = generate_keypair()
+        path.write_text(pub + "\n")
+        key_path = tmp_path / "client.key.pem"
+        key_path.write_bytes(pem)
+        priv = load_private_key(key_path)
+
+        monkeypatch.setattr("browser_cli.client._resolve_socket", _mock_no_browser)
+
+        client, server = _pair()
+        t = threading.Thread(
+            target=_handle_client,
+            args=(server, ("127.0.0.1", 9999), None, path),
+            daemon=True,
+        )
+        t.start()
+
+        challenge = _recv_framed(client)
+        nonce = bytes.fromhex(challenge["nonce"])
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": FAKE_UA, "pubkey": pub}
+        msg["sig"] = sign(priv, nonce, msg).hex()
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+
+        assert resp["success"] is False
+        assert "unauthorized" not in resp["error"].lower()
+        assert "browser" in resp["error"].lower() or "connected" in resp["error"].lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_uppercase_pubkey_normalized_by_compat(self, tmp_path, monkeypatch):
+        """Clients < 0.9.3 may send uppercase pubkeys; compat layer normalises before auth."""
+        path = tmp_path / "authorized_keys"
+        pem, pub = generate_keypair()  # pub is lowercase hex
+        path.write_text(pub + "\n")
+        key_path = tmp_path / "client.key.pem"
+        key_path.write_bytes(pem)
+        priv = load_private_key(key_path)
+
+        monkeypatch.setattr("browser_cli.client._resolve_socket", _mock_no_browser)
+
+        client, server = _pair()
+        t = _spawn(server, path)
+
+        challenge = _recv_framed(client)
+        nonce = bytes.fromhex(challenge["nonce"])
+        # old client sends uppercase pubkey
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": "browser-cli/0.9.2", "pubkey": pub.upper()}
+        msg["sig"] = sign(priv, nonce, msg).hex()
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+
+        assert "unauthorized" not in resp.get("error", "").lower()
+        assert "browser" in resp.get("error", "").lower() or "connected" in resp.get("error", "").lower()
+        client.close()
+        t.join(timeout=2)
+
+    def test_no_auth_mode_reaches_proxy(self, monkeypatch):
+        """auth_keys_path=None (--no-auth): no pubkey required, reaches proxy layer."""
+        monkeypatch.setattr("browser_cli.client._resolve_socket", _mock_no_browser)
+
+        client, server = _pair()
+        t = threading.Thread(
+            target=_handle_client,
+            args=(server, ("127.0.0.1", 9999), None, None),
+            daemon=True,
+        )
+        t.start()
+
+        _recv_framed(client)  # challenge
+        msg = {"id": "x", "command": "tabs.list", "args": {}, "user_agent": FAKE_UA}
+        _send_framed(client, json.dumps(msg).encode())
+        resp = _recv_framed(client)
+
+        assert "unauthorized" not in resp.get("error", "").lower()
+        client.close()
+        t.join(timeout=2)