pr-implement

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 $plan (after $pr-research) or repo URL

When to Use:

• Implementing a planned OSS contribution
• Need isolation enforcement for clean PRs
• After completing $pr-research and $plan

When NOT to Use:

• Internal project work (use $implement)
• Haven't planned yet (run $pr-research then $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-research then $plan first |

Examples

Implement From Contribution Plan

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

What happens:

1. Run pre-checks for branch and scope isolation.
2. Implement only in planned files/areas.
3. 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:

1. Inspect commit/file patterns against stated scope.
2. Flag mixed concerns and suggest extraction steps.
3. 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 |

Local Resources

scripts/

• scripts/validate.sh