re-cinq/internal/skill/skills/line-preview

/line-preview

Read-only preview of what the assembly line would change. Shows what's different on station branches compared to the watched branch — the actual content, not the commit history. No branches are modified.

When to use

Use this skill to see what the assembly line has changed before picking up the changes with /line-rebase.

Procedure

All commands below are read-only — no branches are checked out, modified, or created.

1. Read config: Read line.yaml to determine the watched branch and the ordered list of stations.

2. Check for stations: If no stations are configured, report "No stations configured" and stop.

3. Identify the terminal station: The terminal station is the last in the list. Its branch is line/stn/<terminal-name>.

4. Check terminal branch exists: Run:

   git rev-parse --verify line/stn/<terminal-name>
   

   If this fails, report "The assembly line hasn't run yet — no station branches exist" and stop.

5. Count unpicked commits: Run:

   git rev-list --count <watched>..line/stn/<terminal-name>
   

   If the count is 0, report "No unpicked changes — the watched branch is up to date with the terminal station" and stop.

6. Show what changed overall: Show the diff from the watched branch to the terminal station — this is what /line-rebase would introduce:

   git diff <watched>...line/stn/<terminal-name>
   

7. Show per-station breakdown: For each station in order, show what it changed. The predecessor of the first station is the watched branch; for subsequent stations, the predecessor is the previous station's branch.

   For each station:

   git rev-list --count <predecessor>..line/stn/<station-name>
   

   • If the branch doesn't exist, note "branch not found (station may not have run yet)" and skip.
   • If the count is 0, skip (station ran but produced no changes).
   • Otherwise show the diff:

     git diff <predecessor>...line/stn/<station-name>
     

8. Summarize: Describe what is different — the specific content changes each station introduced. Don't describe commit counts, passes, or process. Suggest running /line-rebase to pick up the changes.

Important

• This is a read-only inspection — do NOT checkout, merge, rebase, or modify any branches
• Use triple-dot (...) for diff (symmetric difference)
• Use double-dot (..) for rev-list (commit range)
• Focus on what changed (added lines, removed code, new sections), not how many commits or how many passes
• If a mid-chain station branch is missing, skip it in the breakdown but continue with subsequent stations (using the last valid predecessor)