Reverse OpenSpec Baseline

Generate source-of-truth specs under openspec/specs/ from existing code. This is how a brownfield repository gets a meaningful capability snapshot instead of starting from an empty openspec/specs/ directory.

Inputs

One of:

• --baseline — scan the whole repository and generate specs for every capability found
• a single capability name — generate or update just that one spec

Optional: --include <path> / --exclude <path> to scope the scan.

Step 0: Ensure the OpenSpec Skeleton Exists