Very good points, thanks! We will be exposing a lot more configurability and extensibility in Sourcegraph in the next release (3.0-preview, and 3.0 more generally). I will add Kythe support to our roadmap and will think about how we can offer a strict mode soon. (We will need to offer that when Sourcegraph supports "write" functionality like automated refactoring, but it would be great to have it sooner.)