implement

name	implement
description	Executes implementation plan with quality checks and progress tracking. Follows AGENTS.md patterns strictly.

Implement Skill

Executes the validated plan systematically, task by task, with verification at each step.

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Agent Compatibility

• TodoWrite: use the tool in Claude Code; in Codex CLI, use update_plan or a simple checklist.
• OUTPUT_DIR: .claude/output for Claude Code, .codex/output for Codex CLI.

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Phase 1: Preparation

1.1 Load Context

Before writing any code:

Required Reading (in order):
├── AGENTS.md                    ← Project patterns & conventions (read first, always)
├── plan-{feature}.md            ← Implementation plan
├── research-{feature}.md        ← Research context
└── Reference files from plan    ← Similar existing implementations

1.2 Context Checklist

□ AGENTS.md fully read — understand state management, models, styling, widget structure
□ Plan fully loaded — all tasks, dependencies, and acceptance criteria known
□ Reference code reviewed — similar existing implementations identified

1.3 Initialize Task Tracking

Set up progress tracking before starting:

TodoWrite (Claude Code) or update_plan (Codex CLI):
  T1: {title} — pending
  T2: {title} — pending
  ...all tasks from plan

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Phase 2: Execution

2.1 Task Execution Order

For each task in dependency order:

1. Mark task in_progress
2. Read related existing code (don't assume — verify)
3. Implement following AGENTS.md patterns exactly
4. Verify acceptance criteria
5. Run lint / analyze
6. Mark task completed
7. Move to next task

One task at a time. Never skip ahead.

2.2 Implementation Rules

1. Follow AGENTS.md patterns EXACTLY — check before writing every new file
2. Use existing components — don't rebuild what already exists
3. No scope creep — only implement what's in the plan
4. No hardcoded values — use project constants (check AGENTS.md for names)
5. Define constants ONCE, reference everywhere
6. Verify library behavior from docs or source — never assume

2.3 Per-Task Verification

After each task, confirm:

□ Code compiles (no errors)
□ Lint passes
□ Follows AGENTS.md patterns
□ All acceptance criteria for this task met
□ No unplanned code added

2.4 If Implementation Hits a Problem

Minor issue (typo, wrong import):
  → Fix and continue

Design issue (plan is wrong for this layer):
  → Stop, revise plan, re-audit if significant

Fundamental issue (research was incomplete):
  → Stop, return to research phase

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Phase 3: Verification

After all tasks complete:

□ All tasks marked completed
□ Full lint / analyze passes
□ Feature works as specified (review acceptance criteria)
□ No regressions in existing functionality
□ No hardcoded values

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Phase 4: Code Review (Auto-Triggered)

After verification, trigger code review:

Claude Code: Use Task tool with subagent_type: "code-reviewer"
Other agents: Invoke /code-review skill

Scope: all new and modified files from the plan's file inventory

The code review covers correctness, security, performance, and pattern compliance.

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Output Summary

After implementation complete:

# Implementation Summary: {Feature Name}

## Status
- Tasks Completed: {X}/{Total}
- Lint: {PASS/FAIL}
- Pattern compliance: {PASS/FAIL}

## Files Changed

### Created
| File | Purpose |
|------|---------|
| `path` | {purpose} |

### Modified
| File | Changes |
|------|---------|
| `path` | {changes} |

## Deviations from Plan
{Any deviations and reasons, or "None"}

## Next Steps
1. Code review (triggered)
2. {other items}

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Quick Commands

/implement           — Start implementation from plan
/implement continue  — Continue from last checkpoint
/implement task T5   — Start from specific task
/implement verify    — Run verification only