1---
2name: pr-commit-splitter-draft-pr
3description: Use when the user wants a large GitHub PR split into logical review commits without rewriting the real PR branch, by rebuilding the changes on a separate draft PR branch and posting that draft PR back on the original PR.
4---
5 
6# PR Commit Splitter Draft PR Mode
7 
8Create reviewable commit history from one large PR without force-pushing the original review branch.
9 
10## When To Use
11 
12Use this flow when at least one condition is true:
13- 12 or more changed files
14- 500 or more changed lines
15- The user explicitly asks for logical commit splitting
16- The user wants the original PR branch left untouched
17 
18## Required Tools
19 
20- `git`
21- `gh`
22 
23Stop if GitHub CLI is not authenticated or the current repository is not connected to the target PR.
24 
25## Safe Workflow
26 
271. Capture baseline state:
28   - `git status --short`
29   - `git fetch origin`
30   - `gh pr view --json number,title,url,headRefName,baseRefName`
31   - `git stash list`
32   - `git branch --show-current`
332. Resolve the real PR context:
34   - Treat the PR head branch as read-only.
35   - Treat the PR base branch as the source for the draft split branch.
36   - Create a draft split branch name like `pr-<number>-split-draft`.
373. Create the scratch branch from the latest base:
38   - `git switch -c pr-<number>-split-draft --track origin/<baseRefName>` when no local branch exists.
39   - If the branch already exists locally, reset expectations first and confirm it is safe to reuse before continuing.
404. Propose commit groups by file sets, not line-by-line by default.
415. Rebuild the PR as a review stack on the scratch branch:
42   - For each group, restore files from the real PR head branch onto the scratch branch:
43     - `git restore --source origin/<headRefName> --staged --worktree -- <group files>`
44   - Commit each group with a coherent message.
456. Verify the scratch branch reproduces the real PR tree:
46   - Compare trees directly, not commit history:
47     - `git diff --stat origin/<headRefName> HEAD`
48   - Stop if the final tree differs.
497. Push the scratch branch:
50   - `git push -u origin pr-<number>-split-draft`
518. Open a draft PR against the same base branch:
52   - `gh pr create --draft --base <baseRefName> --head pr-<number>-split-draft`
539. Comment on the original PR with:
54   - The draft PR URL
55   - The ordered commit list
56   - Per-commit compare links for review
5710. Return to the original branch when finished.
58 
59## Default Commit Grouping Order
60 
611. Domain or contract changes
622. Persistence or infra changes
633. Runtime handlers, controllers, or workers
644. Application wiring
655. Tests
666. Tooling or chore files
67 
68Keep each commit independently reviewable.
69 
70## Comment Payload
71 
72Post one concise comment on the original PR with this structure:
73 
74```text
75Created a draft review stack for this PR:
76- Draft PR: <url>
77- Commit 1: <subject> (<compare-url>)
78- Commit 2: <subject> (<compare-url>)
79- Commit 3: <subject> (<compare-url>)
80 
81The original PR branch was left unchanged.
82```
83 
84Prefer compare links of the form:
85- First commit: `<repo>/compare/<base_sha>...<commit_sha>`
86- Later commits: `<repo>/compare/<previous_commit_sha>...<commit_sha>`
87 
88## Prehook Failure Recovery
89 
90If a commit fails because hooks need dependent files:
911. Read the hook output.
922. Restore only the missing files from `origin/<headRefName>`.
933. Add them to the same commit and retry once.
944. If the dependency boundary becomes unclear, stop and explain the blocker.
95 
96## Safety Rules
97 
98- Never force-push the original PR branch.
99- Never rewrite the original PR branch in place.
100- Do not use destructive commands such as `git reset --hard`.
101- Do not drop or overwrite user stash entries.
102- Stop immediately if branch reuse, tree verification, or PR comment targeting is ambiguous.
103