fix: handle Windows drive letters in update_claude_config

Before this fix, `update_claude_config` would incorrectly split Windows paths
like `C:\Users\foo\server.py` on the drive letter colon, treating
`\Users\foo\server.py` as an object suffix. This would generate broken config
entries that made MCP servers unlaunchable from Claude Desktop on Windows.

Apply the same Windows drive-letter detection logic already present in
`_parse_file_path` (cli.py:97-102): check if position 1 is a colon, and if so,
only consider colons after position 2 as object-suffix separators.

Add test coverage for Windows paths with and without `:object` suffixes.

Co-authored-by: Felix Weinberger <felixweinberger@users.noreply.github.com>

Author: claude[bot]

src/mcp/cli/claude.py

@@ -115,7 +115,11 @@ def update_claude_config(
 
         # Convert file path to absolute before adding to command
         # Split off any :object suffix first
-        if ":" in file_spec:
+        # First check if we have a Windows path (e.g., C:\...)
+        has_windows_drive = len(file_spec) > 1 and file_spec[1] == ":"
+
+        # Split on the last colon, but only if it's not part of the Windows drive letter
+        if ":" in (file_spec[2:] if has_windows_drive else file_spec):
             file_path, server_object = file_spec.rsplit(":", 1)
             file_spec = f"{Path(file_path).resolve()}:{server_object}"
         else:

tests/cli/test_claude.py

@@ -115,3 +115,39 @@ def fake_which(cmd: str) -> str | None:
 
     monkeypatch.setattr("shutil.which", fake_which)
     assert get_uv_path() == expected
+
+
+def test_windows_drive_letter_without_object(config_dir: Path, monkeypatch: pytest.MonkeyPatch):
+    """Windows paths like C:\\path\\server.py without :object should not split on drive letter."""
+    # Mock Path.resolve to return a fake Windows-style path
+    original_resolve = Path.resolve
+
+    def fake_resolve(self: Path) -> Path:
+        if str(self) == "C:\\Users\\foo\\server.py":
+            # Return the same path as if it were already resolved
+            return self
+        return original_resolve(self)
+
+    monkeypatch.setattr(Path, "resolve", fake_resolve)
+
+    assert update_claude_config(file_spec="C:\\Users\\foo\\server.py", server_name="s")
+
+    # Should use the full path without splitting on the drive letter colon
+    assert _read_server(config_dir, "s")["args"][-1] == "C:\\Users\\foo\\server.py"
+
+
+def test_windows_drive_letter_with_object(config_dir: Path, monkeypatch: pytest.MonkeyPatch):
+    """Windows paths like C:\\path\\server.py:app should only split on the :app suffix."""
+    original_resolve = Path.resolve
+
+    def fake_resolve(self: Path) -> Path:
+        if str(self) == "C:\\Users\\foo\\server.py":
+            return self
+        return original_resolve(self)
+
+    monkeypatch.setattr(Path, "resolve", fake_resolve)
+
+    assert update_claude_config(file_spec="C:\\Users\\foo\\server.py:app", server_name="s")
+
+    # Should split on :app but not on C:
+    assert _read_server(config_dir, "s")["args"][-1] == "C:\\Users\\foo\\server.py:app"