Add Phase 6 Documentation UX, pattern starter template, and Phase 1 validation snapshot

README.md

@@ -15,6 +15,7 @@ Phase tracking:
 - [Phase 3 — Modern Java implementation variants](docs/phase-3-modern-java-variants.md)
 - [Phase 4 — Cloud-native + observability examples](docs/phase-4-cloud-native-observability.md)
 - [Phase 5 — AI-era additions (high practical value)](docs/phase-5-ai-era-patterns.md)
+- [Phase 6 — Documentation UX for workplace reuse](docs/phase-6-documentation-ux.md)
 
 ---
 
@@ -180,6 +181,16 @@ Package: `src/main/java/org/example/ai`
 
 ---
 
+
+## Documentation UX quick links
+
+- **Decision trees + domain guides**: [`docs/phase-6-documentation-ux.md`](docs/phase-6-documentation-ux.md)
+- **Copy-paste pattern starter**: [`templates/pattern-starter/`](templates/pattern-starter/)
+
+Use these assets when deciding what pattern to use and when scaffolding new pattern examples for workplace reuse.
+
+---
+
 ## Project structure
 
 ```text

docs/phase-1-production-readiness.md

@@ -24,3 +24,20 @@ This tracker converts the initial improvement plan into concrete repository chec
 - Raise JaCoCo line coverage threshold from 35% to at least 50%.
 - Add package-level/module-level coverage rules for critical packages.
 - Add dependency/license scanning (for example, OWASP Dependency-Check).
+
+## Final validation snapshot (2026-04-10)
+
+Phase 1 production-readiness criteria were re-validated after Phase 6 documentation updates.
+
+| Checkpoint | Validation method | Result |
+|---|---|---|
+| Pattern index matrix exists with required columns (`Pattern`, `Intent`, `When to use`, `Trade-offs`, `Real-world example`, `Test class`) | Manual verification in `README.md` | ✅ Pass |
+| Package naming typo migration plan (`singalton` → `singleton`) documented with compatibility/deprecation approach | Manual verification in `README.md` + this phase tracker | ✅ Pass |
+| Quality gates baseline (Checkstyle, SpotBugs, JaCoCo thresholds) enforced through Maven lifecycle | `pom.xml` plugin configuration verification + `mvn verify` execution | ✅ Pass |
+| Environment portability docs for enterprise proxy/mirror setup present | Manual verification in `README.md` build troubleshooting section | ✅ Pass |
+
+Validation command baseline:
+
+```bash
+mvn verify
+```

docs/phase-6-documentation-ux.md

@@ -0,0 +1,150 @@
+# Phase 6 — Documentation UX for workplace reuse
+
+This phase makes the repository faster to navigate and reuse in real delivery teams by adding decision guides, domain-first recipes, and copy-paste starter templates.
+
+## Status overview
+
+| Area | Goal | Deliverable | Status |
+|---|---|---|---|
+| Pattern decision trees | Help engineers answer “Choose this pattern when…” quickly | Decision trees for API/backend, data pipelines, event-driven systems, AI-powered systems | ✅ Completed |
+| Quick decision guides by domain | Reduce choice paralysis for common system types | Domain-specific pattern shortlist + anti-pattern warnings | ✅ Completed |
+| Copy-paste starter templates | Standardize how new pattern examples are added | Starter template bundle with README + code + test + extension points | ✅ Completed |
+| Domain recipes | Show adaptation to enterprise verticals | Fintech, e-commerce, healthcare, logistics tailoring playbooks | ✅ Completed |
+
+---
+
+## Choose this pattern when… (decision trees)
+
+### 1) API/backend systems
+
+1. Need to protect unstable dependencies?
+   - Yes → Start with **Circuit Breaker + Retry + Timeout + Backoff + Idempotency Key**.
+2. Need clean integration boundaries?
+   - Yes → Prefer **Hexagonal Architecture** + **Repository**.
+3. Need read/write scaling and separate models?
+   - Yes → Add **CQRS** (and optionally **Event Sourcing** if full audit/time-travel is required).
+4. Need phased migration from legacy API/domain?
+   - Yes → Use **Strangler Fig** + **Anti-Corruption Layer**.
+
+### 2) Data pipelines
+
+1. Need high-throughput asynchronous flow?
+   - Yes → **Reactive Processing** + **Bulkhead** isolation.
+2. Need reliable downstream event publication from database state changes?
+   - Yes → **Transactional Outbox**.
+3. Need compensating actions across multiple processing stages?
+   - Yes → **Saga** (orchestration first, choreography when domains are stable).
+4. Need filter/composition logic across many business rules?
+   - Yes → **Specification** + **Strategy**.
+
+### 3) Event-driven systems
+
+1. Need in-process broadcast to multiple listeners?
+   - Yes → **Observer**.
+2. Need durable event history/audit replay?
+   - Yes → **Event Sourcing**.
+3. Need message failure handling at scale?
+   - Yes → **Dead Letter Queue** + **Retry with Backoff**.
+4. Need idempotent at-least-once delivery handling?
+   - Yes → **Idempotency Key Store** + explicit dedupe checks.
+
+### 4) AI-powered systems
+
+1. Need consistent prompt construction?
+   - Yes → **Prompt Builder**.
+2. Need grounding via enterprise knowledge?
+   - Yes → **Retrieval Pipeline (RAG-lite)**.
+3. Need tool routing and unified AI entrypoint?
+   - Yes → **Tool/Agent Facade**.
+4. Need robustness across model outages/quality variability?
+   - Yes → **Fallback Model Strategy**.
+5. Need policy/safety controls and repeatable quality scoring?
+   - Yes → **Policy-Enforced LLM Client** + **Evaluation Harness**.
+
+---
+
+## Quick decision guides by domain
+
+### API/backend
+
+**Start here:**
+- Reliability baseline: Retry, Timeout, Circuit Breaker, Idempotency Key.
+- Architecture baseline: Hexagonal + Repository.
+- Migration baseline: Strangler + ACL.
+
+**Avoid:**
+- Introducing CQRS/Event Sourcing before reliability + observability are in place.
+
+### Data pipelines
+
+**Start here:**
+- Reactive Processing, Transactional Outbox, Bulkhead, DLQ.
+- Add Saga when pipeline steps cross service or data ownership boundaries.
+
+**Avoid:**
+- Choreography-first Sagas without clear event contracts and trace IDs.
+
+### Event-driven systems
+
+**Start here:**
+- Observer (local), Outbox + DLQ (distributed), Idempotency (delivery safety).
+- Prefer explicit schema/version policy for events.
+
+**Avoid:**
+- Assuming exactly-once delivery semantics without deduplication design.
+
+### AI-powered systems
+
+**Start here:**
+- Prompt Builder + Retrieval Pipeline + Policy-Enforced LLM Client.
+- Add Fallback Model Strategy for availability.
+- Use Evaluation Harness to gate prompt/model changes.
+
+**Avoid:**
+- Shipping AI flows without policy checks, redaction, and offline evaluation sets.
+
+---
+
+## Copy-paste starter templates
+
+Use `templates/pattern-starter/` as the canonical scaffold whenever introducing a new pattern sample.
+
+Template contents:
+- `README.md` — pattern intent, when to use, trade-offs, and rollout guidance.
+- `src/main/java/.../PatternTemplate.java` — minimal production-style implementation.
+- `src/test/java/.../PatternTemplateTest.java` — executable behavior checks.
+- `EXTENSION_POINTS.md` — explicit customization hooks for workplace adaptation.
+
+This standard is intended to be replicated **for every new pattern contribution**.
+
+---
+
+## Domain recipes (adaptation playbooks)
+
+### Fintech
+- Prioritize: Idempotency Key, Event Sourcing, Saga, Retry with bounded backoff.
+- Add: strict audit trails, PII masking policies, deterministic evaluation harnesses for AI-assisted decisions.
+- Guardrails: monetary operations must be replay-safe and duplicate-resistant.
+
+### E-commerce
+- Prioritize: CQRS, Saga orchestration, Circuit Breaker, Cache-friendly read models.
+- Add: inventory reservation compensation strategies, burst traffic rate limits.
+- Guardrails: protect checkout path with latency budgets and timeout defaults.
+
+### Healthcare
+- Prioritize: ACL, Repository + Specification, Policy-Enforced AI wrappers.
+- Add: traceability and privacy-first defaults (PII masking, least-privilege data flow).
+- Guardrails: immutable audit events and deterministic rollback/compensation for critical workflows.
+
+### Logistics
+- Prioritize: Event-driven choreography/orchestration, Bulkhead, DLQ, Retry.
+- Add: geo/route strategy modules and state-machine based workflow transitions.
+- Guardrails: isolate partner integration failures and preserve eventually consistent shipment state.
+
+---
+
+## Suggested acceptance criteria for this phase
+
+- Domain leads can select a starting pattern set in under 5 minutes.
+- New contributors can scaffold a pattern example from template assets in under 15 minutes.
+- Reviewers can verify extension points and tests exist before approving new pattern additions.

templates/pattern-starter/EXTENSION_POINTS.md

@@ -0,0 +1,21 @@
+# Extension Points
+
+Document how teams should adapt the pattern safely.
+
+## Required extension points
+
+1. **Domain policy hook**
+   - Where business validation rules are injected.
+2. **Integration adapter hook**
+   - Where external system calls are abstracted.
+3. **Observability hook**
+   - Where tracing/metrics/logging can be added.
+4. **Failure strategy hook**
+   - Where retry/timeout/circuit-break behavior can be configured.
+
+## Workplace adaptation checklist
+
+- Fintech: add idempotency and immutable audit IDs.
+- E-commerce: add timeout budgets and stock consistency rules.
+- Healthcare: add privacy filters and access-control checks.
+- Logistics: add routing strategy and asynchronous compensation hooks.

templates/pattern-starter/README.md

@@ -0,0 +1,31 @@
+# Pattern Starter Template
+
+Use this folder as the base for adding a new pattern to the repository.
+
+## What to include
+
+1. **Intent**: one sentence on the design problem solved.
+2. **When to use**: concrete triggering conditions.
+3. **Trade-offs**: at least two downside risks.
+4. **Real-world mapping**: one enterprise scenario.
+5. **How to run tests**: exact Maven command.
+
+## Pattern metadata checklist
+
+- Pattern name:
+- Category (creational/structural/behavioral/enterprise/etc.):
+- Target package:
+- Key dependencies (if any):
+- Related test class:
+
+## Required files
+
+- `src/main/java/.../PatternTemplate.java`
+- `src/test/java/.../PatternTemplateTest.java`
+- `EXTENSION_POINTS.md`
+
+## Definition of done
+
+- Example compiles.
+- Test verifies positive and negative/edge behavior.
+- Extension points documented for workplace customization.

templates/pattern-starter/src/main/java/org/example/template/PatternTemplate.java

@@ -0,0 +1,16 @@
+package org.example.template;
+
+/**
+ * Minimal starter class for a new pattern contribution.
+ */
+public class PatternTemplate {
+    private final String input;
+
+    public PatternTemplate(String input) {
+        this.input = input;
+    }
+
+    public String execute() {
+        return "processed:" + input;
+    }
+}

templates/pattern-starter/src/test/java/org/example/template/PatternTemplateTest.java

@@ -0,0 +1,14 @@
+package org.example.template;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class PatternTemplateTest {
+
+    @Test
+    void executeShouldPrefixProcessed() {
+        PatternTemplate template = new PatternTemplate("sample");
+        assertEquals("processed:sample", template.execute());
+    }
+}