implement-fix

name	implement-fix
description	Implements a bug fix for a GitHub issue based on its RCA document, adds regression tests, and validates. Use after an RCA document exists and you are ready to fix the issue.
argument-hint	["github-issue-id"]
allowed-tools	Read, Write, Edit, Bash(ruff:*), Bash(mypy:*), Bash(pytest:*), Bash(npm:*), Bash(bun:*)

Implement Fix: GitHub Issue #$ARGUMENTS

Prerequisites

This skill implements fixes for GitHub issues based on RCA documents:

• Working in a local Git repository with GitHub origin
• RCA document exists at docs/rca/issue-$ARGUMENTS.md
• GitHub CLI installed and authenticated (optional, for status updates)

RCA Document to Reference

Read RCA: docs/rca/issue-$ARGUMENTS.md

Optional - View GitHub issue for context:

gh issue view $ARGUMENTS

Implementation Instructions

1. Read and Understand RCA

• Read the ENTIRE RCA document thoroughly
• Review the GitHub issue details (issue #$ARGUMENTS)
• Understand the root cause
• Review the proposed fix strategy
• Note all files to modify
• Review testing requirements

2. Verify Current State

Before making changes:

• Confirm the issue still exists
• Check current state of affected files
• Review any recent changes to those files

3. Implement the Fix

Following the "Proposed Fix" section of the RCA:

For each file to modify:

a. Read the existing file

• Understand current implementation
• Locate the specific code mentioned in RCA

b. Make the fix

• Implement the change as described in RCA
• Follow the fix strategy exactly
• Maintain code style and conventions
• Add comments if the fix is non-obvious

c. Handle related changes

• Update any related code affected by the fix
• Ensure consistency across the codebase
• Update imports if needed

4. Add/Update Tests

Following the "Testing Requirements" from RCA:

Create test cases for:

1. Verify the fix resolves the issue
2. Test edge cases related to the bug
3. Ensure no regression in related functionality
4. Test any new code paths introduced

Test file location:

• Follow project's test structure
• Mirror the source file location
• Use descriptive test names

Test implementation:

def test_issue_$ARGUMENTS_fix():
    """Test that issue #$ARGUMENTS is fixed."""
    # Arrange - set up the scenario that caused the bug
    # Act - execute the code that previously failed
    # Assert - verify it now works correctly

5. Run Validation

Execute validation commands from RCA:

# Run linters
[from RCA validation commands]

# Run type checking
[from RCA validation commands]

# Run tests
[from RCA validation commands]

If validation fails:

• Fix the issues
• Re-run validation
• Don't proceed until all pass

6. Verify Fix

Manually verify:

• Follow reproduction steps from RCA
• Confirm issue no longer occurs
• Test edge cases
• Check for unintended side effects

7. Update Documentation

If needed:

• Update code comments
• Update API documentation
• Update README if user-facing
• Add notes about the fix

Output Report

Fix Implementation Summary

GitHub Issue #$ARGUMENTS: [Brief title]

Issue URL: [GitHub issue URL]

Root Cause (from RCA): [One-line summary of root cause]

Changes Made

Files Modified:

1. [file-path]

   • Change: [What was changed]
   • Lines: [Line numbers]

2. [file-path]

   • Change: [What was changed]
   • Lines: [Line numbers]

Tests Added

Test Files Created/Modified:

1. [test-file-path]
   • Test cases: [List test functions added]

Test Coverage:

• ✅ Fix verification test
• ✅ Edge case tests
• ✅ Regression prevention tests

Validation Results

# Linter output
[Show lint results]

# Type check output
[Show type check results]

# Test output
[Show test results - all passing]

Verification

Manual Testing:

• ✅ Followed reproduction steps - issue resolved
• ✅ Tested edge cases - all pass
• ✅ No new issues introduced
• ✅ Original functionality preserved

Files Summary

Total Changes:

• X files modified
• Y files created (tests)
• Z lines added
• W lines removed

Ready for Commit

All changes complete and validated. Ready for the commit skill.

Suggested commit message:

fix(scope): resolve GitHub issue #$ARGUMENTS - [brief description]

[Summary of what was fixed and how]

Fixes #$ARGUMENTS

Note: Using Fixes #$ARGUMENTS in the commit message will automatically close the GitHub issue when merged to the default branch.

Optional: Update GitHub Issue

Add implementation comment to issue:

gh issue comment $ARGUMENTS --body "Fix implemented in commit [commit-hash]. Ready for review."

Update issue labels (if needed):

gh issue edit $ARGUMENTS --add-label "fixed" --remove-label "bug"

Close the issue (if not using auto-close via commit message):

gh issue close $ARGUMENTS --comment "Fixed and merged."

Notes

• If the RCA document is missing or incomplete, request it be created first with the rca skill for issue #$ARGUMENTS
• If you discover the RCA analysis was incorrect, document findings and update the RCA
• If additional issues are found during implementation, note them for separate GitHub issues and RCAs
• Follow project coding standards exactly
• Ensure all validation passes before declaring complete
• The commit message Fixes #$ARGUMENTS will link the commit to the GitHub issue