implementation-approach

name	implementation-approach
description	This skill provides implementation strategy selection framework with meta-cognitive approach, verification levels, and integration point definitions. Automatically loaded when planning implementation strategy, selecting development approach, defining verification criteria, or when "vertical slice", "horizontal slice", "verification level", or "implementation strategy" are mentioned.

Implementation Strategy Selection Framework (Meta-cognitive Approach)

Meta-cognitive Strategy Selection Process

Phase 1: Comprehensive Current State Analysis

Core Question: "What does the existing implementation look like?"

Analysis Framework

Architecture Analysis: Responsibility separation, data flow, dependencies, technical debt
Implementation Quality Assessment: Code quality, test coverage, performance, security
Historical Context Understanding: Current form rationale, past decision validity, constraint changes, requirement evolution

Meta-cognitive Question List

• What is the true responsibility of this implementation?
• Which parts are business essence and which derive from technical constraints?
• What dependencies or implicit preconditions are unclear from the code?
• What benefits and constraints does the current design bring?

Phase 2: Strategy Exploration and Creation

Core Question: "When determining before → after, what implementation patterns or strategies should be referenced?"

Strategy Discovery Process

Research and Exploration: Tech stack examples (WebSearch), similar projects, OSS references, literature/blogs
Creative Thinking: Strategy combinations, constraint-based design, phase division, extension point design

Reference Strategy Patterns (Creative Combinations Encouraged)

Legacy Handling Strategies:

• Strangler Pattern: Gradual migration through phased replacement
• Facade Pattern: Complexity hiding through unified interface
• Adapter Pattern: Bridge with existing systems

New Development Strategies:

• Feature-driven Development: Vertical implementation prioritizing user value
• Foundation-driven Development: Foundation-first construction prioritizing stability
• Risk-driven Development: Prioritize addressing maximum risk elements

Integration/Migration Strategies:

• Proxy Pattern: Transparent feature extension
• Decorator Pattern: Phased enhancement of existing features
• Bridge Pattern: Flexibility through abstraction

Important: The optimal solution is discovered through creative thinking according to each project's context.

Phase 3: Risk Assessment and Control

Core Question: "What risks arise when applying this to existing implementation, and what's the best way to control them?"

Risk Analysis Matrix

Technical Risks: System impact, data consistency, performance degradation, integration complexity
Operational Risks: Service availability, deployment downtime, process changes, rollback procedures
Project Risks: Schedule delays, learning costs, quality achievement, team coordination

Risk Control Strategies

Preventive Measures: Phased migration, parallel operation verification, integration/regression tests, monitoring setup
Incident Response: Rollback procedures, log/metrics preparation, communication system, service continuation procedures

Phase 4: Constraint Compatibility Verification

Core Question: "What are this project's constraints?"

Constraint Checklist

Technical Constraints: Library compatibility, resource capacity, mandatory requirements, numerical targets
Temporal Constraints: Deadlines/priorities, dependencies, milestones, learning periods
Resource Constraints: Team/skills, work hours/systems, budget, external contracts
Business Constraints: Market launch timing, customer impact, regulatory compliance

Phase 5: Implementation Approach Decision

Select optimal solution from basic implementation approaches (creative combinations encouraged):

Vertical Slice (Feature-driven)

Characteristics: Vertical implementation across all layers by feature unit Application Conditions: Low inter-feature dependencies, output in user-usable form, changes needed across all architecture layers Verification Method: End-user value delivery at each feature completion

Horizontal Slice (Foundation-driven)

Characteristics: Phased construction by architecture layer Application Conditions: Foundation system stability important, multiple features depend on common foundation, layer-by-layer verification effective Verification Method: Integrated operation verification when all foundation layers complete

Hybrid (Creative Combination)

Characteristics: Flexible combination according to project characteristics Application Conditions: Unclear requirements, need to change approach per phase, transition from prototyping to full implementation Verification Method: Verify at appropriate L1/L2/L3 levels according to each phase's goals

Phase 6: Decision Rationale Documentation

Design Doc Documentation: Clearly specify implementation strategy selection reasons and rationale.

Verification Level Definitions

Priority for completion verification of each task:

• L1: Functional Operation Verification - Operates as end-user feature (e.g., search executable)
• L2: Test Operation Verification - New tests added and passing
• L3: Build Success Verification - Code builds/runs without errors

Priority: L1 > L2 > L3 in order of verifiability importance

Integration Point Definitions

Define integration points according to selected strategy:

• Strangler-based: When switching between old and new systems for each feature
• Feature-driven: When users can actually use the feature
• Foundation-driven: When all architecture layers are ready and E2E tests pass
• Hybrid: When individual goals defined for each phase are achieved

Anti-patterns

• Pattern Fixation: Selecting only from listed strategies without considering unique combinations
• Insufficient Analysis: Skipping Phase 1 analysis framework before strategy selection
• Risk Neglect: Starting implementation without Phase 3 risk analysis matrix
• Constraint Ignorance: Deciding strategy without checking Phase 4 constraint checklist
• Rationale Omission: Selecting strategy without using Phase 6 documentation template

Guidelines for Meta-cognitive Execution

1. Leverage Known Patterns: Use as starting point, explore creative combinations
2. Active WebSearch Use: Research implementation examples from similar tech stacks
3. Apply 5 Whys: Pursue root causes to grasp essence
4. Multi-perspective Evaluation: Comprehensively evaluate from each Phase 1-4 perspective
5. Creative Thinking: Consider sequential application of multiple strategies and designs leveraging project-specific constraints
6. Clarify Decision Rationale: Make strategy selection rationale explicit in design documents