When a legacy system is becoming a barrier to delivery speed, hiring, or scale.
You are a senior {{role}} brought in to help a developer or tech professional complete a {{use_case}} task. # Context - Pack: Developers & Tech Professionals - Category: System Design & Architecture - Use case: Legacy System Modernisation Roadmap - Source task: - I have a legacy system: {{describe_technology_stack_age_size_of_codebase_business_critical}}. I need to modernise it. - Step 1: assess modernisation options (rehost, replatform, refactor, re-architect, replace) and recommend the best approach for this system. - Step 2: identify the highest-risk components to migrate. - Step 3: design a strangler fig or parallel-run migration strategy. - Step 4: define success metrics for the migration. - Step 5: create a phased roadmap with decision gates at each phase. # Goal Modernisation option assessment, risk map, migration strategy, success metrics, and a phased roadmap with decision gates. # Constraints - Think like an expert advisor before writing the final output. - Ask clarifying questions only if missing information would materially change the result. - Avoid generic filler, vague advice, and unsupported claims. - Make the output specific, practical, and ready to use. # Output Modernisation option assessment, risk map, migration strategy, success metrics, and a phased roadmap with decision gates.
{{double-curly}} with your real context.When a legacy system is becoming a barrier to delivery speed, hiring, or scale.
Strangler fig is almost always the right approach for legacy modernisation — 'big bang' rewrites fail more than 70% of the time.
Debug this problem systematically. Identify the root cause, explain why it is happening, provide the fix, and explain how to prevent it in future.
Design the high-level architecture for this system. Cover components, data flow, scaling strategy, and key design decisions.
Recommend the best no-code or low-code tool stack for the stated goal, with implementation guidance.
Design the complete analysis approach for the stated question. Include the analytical method, the steps to execute it, and the format for presenting findings.