Conversations around the development of sourcekit-bazel-bsp are currently being hosted on the official Bazel Community Slack. We are over at #sourcekit-bazel-bsp and everyone is welcome to join!
If you're using Xcode, you can develop for sourcekit-bazel-bsp by directly opening Package.swift file in Xcode. After building, you can test your custom binary by changing the path to sourcekit-bazel-bsp in your test project's BSP json file as described in the Initial Setup instructions.
Download and install the official Swift extension for Cursor / VSCode. After this, the IDE should properly recognize sourcekit-bazel-bsp as a SwiftPM project and automatically generate the relevant build/debug actions. After building, you can test your custom binary by changing the path to sourcekit-bazel-bsp in your test project's BSP json file as described in the Initial Setup instructions.
Instructions on how to debug sourcekit-bazel-bsp and enable extended logging are currently available at the main README.