Describe a Commit

Generate and set a commit description. Defaults to @ (working copy), but typically used on @- (parent) when working copy is empty.

Process

1. Run jj show <rev> --summary and jj diff -r <rev> --stat to get change overview (use @- for parent)
2. Analyze changes:
   • Small (≤5 files, ≤200 lines): run jj diff -r <rev> directly
   • Large: use /jj-context for structured summary
3. Determine project prefix from file paths
4. Generate a one-line description: <prefix>: <lowercase verb> <what changed>
5. Run jj describe <rev> -m "<description>" (e.g., jj describe @- -m "...")

IMPORTANT: Always use a single-line commit message. Never use multi-line descriptions or bullet points.

Project Prefix Examples

Use the descriptive folder path identifying the subsystem:

• src/auth for authentication code
• lib/utils for utility libraries
• services/api for API services
• db/migrations for database changes

Good Description Examples

• src/auth: add JWT token refresh logic
• lib/utils: fix date parsing for ISO formats
• services/api: add rate limiting middleware
• db/migrations: add users table
• tests/integration: add checkout flow tests