pr-implement

SKILL.md

PR Implement Skill

Fork-based implementation for open source contributions with mandatory isolation check.

Overview

Execute a contribution plan with fork isolation. Ensures PRs are clean
and focused by running isolation checks before and during implementation.

Input: Plan artifact from $pr-plan or repo URL

When to Use:

Implementing a planned OSS contribution

Need isolation enforcement for clean PRs

After completing $pr-plan

When NOT to Use:

Internal project work (use $implement)

Haven't planned yet (run $pr-plan first)

Workflow

-1. Prior Work Check      -> BLOCKING: Check for competing PRs
0.  Input Discovery       -> Find plan artifact or repo
1.  Fork Setup            -> Ensure fork exists and is current
2.  Worktree Creation     -> Create isolated worktree
3.  Isolation Pre-Check   -> BLOCK if mixed concerns
4.  Implementation        -> Execute plan
5.  Isolation Post-Check  -> BLOCK if scope creep
6.  Commit Preparation    -> Stage with proper commit type
7.  Handoff               -> Ready for $pr-prep

Phase -1: Prior Work Check (BLOCKING)

# Search for open PRs on this topic
gh pr list -R <owner/repo> --state open --search "<topic>" --limit 10

# Check target issue status
gh issue view <issue-number> -R <repo> --json state,assignees

Finding
Action

Open PR exists
Coordinate or wait

Issue assigned
Coordinate or find alternative

No competing work
Proceed

Phase 3: Isolation Pre-Check (BLOCKING)

# Commit type analysis
git log --oneline main..HEAD | sed 's/^[^ ]* //' | grep -oE '^[a-z]+(\([^)]+\))?:' | sort -u

# File theme analysis
git diff --name-only main..HEAD | cut -d'/' -f1-2 | sort -u

Check
Pass Criteria

Single commit type
0 or 1 prefix

Thematic files
All match plan scope

Branch fresh
Based on recent main

DO NOT PROCEED IF PRE-CHECK FAILS.

Phase 4: Implementation

Guidelines

Guideline
Why

Single concern
Each commit = one logical change

Match conventions
Follow project style exactly

Test incrementally
Run tests after each change

Commit Convention

git commit -m "type(scope): brief description

Longer explanation if needed.

Related: #issue-number"

Phase 5: Isolation Post-Check (BLOCKING)

# Commit type analysis
git log --oneline main..HEAD | sed 's/^[^ ]* //' | grep -oE '^[a-z]+(\([^)]+\))?:' | sort -u

# Summary stats
git diff --stat main..HEAD

Check
Pass Criteria

Single commit type
All commits share same prefix

Thematic files
All files relate to PR scope

Atomic scope
Can explain in one sentence

Phase 7: Handoff

Implementation complete. Isolation checks passed.

Branch: origin/$BRANCH_NAME
Commits: N commits, +X/-Y lines

Next step: $pr-prep

Anti-Patterns

DON'T
DO INSTEAD

Skip isolation pre-check
Run Phase 3 FIRST

Skip isolation post-check
Run Phase 5 before push

Mix concerns in commits
One type prefix per PR

Implement without plan
Run $pr-plan first

Examples

Implement From Contribution Plan

User says: "Implement this external PR plan with isolation checks."

What happens:

Run pre-checks for branch and scope isolation.

Implement only in planned files/areas.

Run post-checks and prepare handoff for PR prep.

Enforce Single-Concern Commit Set

User says: "Make sure this branch is still single-purpose before I prep the PR."

What happens:

Inspect commit/file patterns against stated scope.

Flag mixed concerns and suggest extraction steps.

Produce a clean handoff to $pr-prep.

Troubleshooting

Problem
Cause
Solution

Isolation check fails
Unrelated changes on branch
Move unrelated edits to separate branch/PR

Commits mix concerns
Implementation drifted from plan
Re-split commits by concern and revalidate

Scope keeps expanding
Weak boundaries in plan
Re-anchor to Out of Scope and stop additional changes

Hard to hand off
Missing summary/test context
Add concise change summary and verification notes