PromptForge Academy
ADVANCEDexisting projectDoc2_Existing_Project_Analysis_Debugging_Updating.docx

Advanced — Existing Project Analysis & Modernization

Reading, debugging, and safely changing production codebases with Claude

For engineers inheriting, maintaining, or modernising production systems. Codebase archaeology, scientific debugging across stack traces, memory leaks, deadlocks, and distributed traces. SEV1 triage and post-mortems. Expand-Contract safe changes. Strangler Fig and CRUD-to-CQRS migration. .NET Framework → .NET 8 modernisation. Golden master testing and STRIDE threat modelling.

Module 1 — Deep Codebase Analysis

Architecture archaeology, layered quality analysis, dependency risk.

Start
  1. 1
    Architecture Archaeology
    Architecture Reverse Engineering prompt; Implicit Contract Discovery prompt.
  2. 2
    Code Quality Analysis (4 dimensions)
    Layered Quality Analysis prompt across structure, complexity, testability, security.
  3. 3
    Dependency & Vulnerability Analysis
    Transitive Dependency Risk prompt — CVE rollup and upgrade path.

Module 2 — Advanced Debugging

Scientific method, stack-trace analysis, memory leaks, deadlocks, distributed tracing.

Start
  1. 1
    Scientific Debugging Method
    6-stage flow: Observe → Hypothesise → Predict → Test → Analyse → Iterate.
  2. 2
    Advanced Stack Trace Analysis
    Multi-Layer Stack Trace Analysis prompt — proximate cause, root cause, contributing factors, blast radius.
  3. 3
    Memory Leak & GC Pressure
    Memory Issue Analysis prompt — 7 leak patterns including event-handler retention, IDisposable misuse, closure capture.
  4. 4
    Concurrency & Deadlock Analysis
    Deadlock Investigation prompt — deadlock vs starvation vs livelock vs races.
  5. 5
    Distributed System Debugging
    Cross-Service Request Tracing prompt — spans, logs, service contracts.

Module 3 — Production Incident Management

SEV classification, war-room prompts, post-mortems.

Start
  1. 1
    Incident Severity Classification
    SEV1–SEV4 table — customer impact, response time, comms cadence.
  2. 2
    War Room Prompt Templates
    SEV1 Rapid Triage prompt — 60-second structured triage update.
  3. 3
    Post-Incident Root Cause Report
    Post-Incident Root Cause Report prompt — what happened, why, blast radius, what we change.

Module 4 — Safe Code Modification

Blast radius analysis, expand-contract, feature flags for safe rollout.

Start
  1. 1
    Change Impact Analysis
    Blast Radius Assessment prompt — what could a change break, who must be informed.
  2. 2
    Expand-Contract Pattern
    Zero-Downtime API Change prompt — 3-phase expand, migrate, contract.
  3. 3
    Feature Flags for Safe Rollout
    Feature Flag Implementation prompt — kill switches, canary cohorts, rollout schedules.

Module 5 — Advanced Refactoring

Strangler Fig, CRUD-to-CQRS migration, anti-patterns.

Start
  1. 1
    Strangler Fig Pattern
    Strangler Fig Migration Plan prompt — seams, routing layer, phase plan, verification.
  2. 2
    Refactoring to CQRS
    Migrate CRUD to CQRS prompt using Branch-by-Abstraction with no breaking changes.
  3. 3
    Refactoring Anti-Patterns
    5-row anti-pattern table — what looks like progress but isn't.

Module 6 — Legacy System Modernization

.NET 4.8 → .NET 8 migration, async/await conversion, monolith extraction.

Start
  1. 1
    .NET Framework to .NET 8 Migration
    Migration Readiness Assessment prompt; Async/Await Migration (8 rules) prompt.
  2. 2
    Monolith to Microservices Extraction
    Module Extraction Strategy prompt — extraction seams, data ownership, deployment plan.

Module 7 — Testing Existing Systems

Golden master, approval testing, load and chaos.

Start
  1. 1
    Golden Master Testing
    Golden Master Test Generation prompt — lock current behaviour before refactoring.
  2. 2
    Approval Testing for Complex Output
    Approval Tests Setup prompt with Verify-style libraries.
  3. 3
    Load & Chaos Testing
    Load Test Scenario Generation prompt — baseline, stress, spike, soak.

Module 8 — Security Analysis

STRIDE threat modelling, deep auth review.

Start
  1. 1
    Threat Modeling with Claude
    STRIDE Threat Model prompt across 6 categories applied to a target service.
  2. 2
    Advanced Security Code Review
    Authentication & Authorization Deep Review prompt — token handling, scope checks, IDOR.

Module 9 — Advanced Workshops

Production incident simulation, legacy modernization, microservice extraction.

Start
  1. 1
    Workshop 1 — Production Incident Simulation
    Live war-room drill against a provided buggy service; SEV1 triage and post-mortem.
  2. 2
    Workshop 2 — Legacy Codebase Modernization
    End-to-end Strangler Fig plan on a provided .NET 4.8 codebase.
  3. 3
    Workshop 3 — Microservice Extraction
    Carve a bounded context out of a monolith with a zero-downtime cutover.

Module 10 — Quality Gates

7-gate framework (G1–G7) for shipping AI-assisted changes safely.

Start
  1. 1
    7 Quality Gates (G1–G7)
    G1 Impact, G2 Tests, G3 Security, G4 Performance, G5 Observability, G6 Docs, G7 Self-Critique. Non-negotiables: G1, G2, G3.
Advanced — Existing Project Analysis & Modernization · PromptForge Academy