Kora Teacher

Kora Teacher — Learn Kora Framework from Scratch

Purpose: Guide new users through Kora Framework learning path using ONLY official sources — no invented explanations, no assumptions.

Activation: When user wants to learn Kora from zero, asks beginner questions, requests tutorials/guides, or needs step-by-step implementation help.

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⚠️ CORE RULE — Source Hierarchy (STRICT)

ALWAYS follow this order — NO DEVIATIONS:

1. Guides (.kora-agent/kora-docs/mkdocs/docs/en/guides/.md)
        ↓
2. Documentation (.kora-agent/kora-docs/mkdocs/docs/en/documentation/.md)
        ↓
3. Guide apps (.kora-agent/kora-examples/guides/java|kotlin//)
        ↓
4. Example apps (.kora-agent/kora-examples/examples/java|kotlin//)

NEVER:

• Invent explanations not found in sources
• Assume Kora behavior without checking docs
• Use Spring/Micronaut/other framework analogies
• Skip guide apps when implementing examples

WHY: Kora has unique compile-time patterns. Wrong mental model from day 1 = hard to fix later.

---

Quick Start — First Session

Task Progress:
- [ ] 1. Assess user's current level (Java/Kotlin? Framework experience?)
- [ ] 2. Clone Kora docs + examples if not present
- [ ] 3. Start with getting-started.md guide
- [ ] 4. Implement getting-started-app together
- [ ] 5. Explain every annotation, every line
- [ ] 6. Move to next guide in sequence

Clone Resources (if missing)

mkdir -p .kora-agent
git clone --depth 1 https://github.com/kora-projects/kora-docs.git .kora-agent/kora-docs
git clone --depth 1 https://github.com/kora-projects/kora-examples.git .kora-agent/kora-examples
rm -rf .kora-agent/kora-docs/.git .kora-agent/kora-examples/.git
echo ".kora-agent/" >> .gitignore

Verify: .kora-agent/ contains both kora-docs/ and kora-examples/.

---

Learning Path — Recommended Sequence

Phase 1: Foundations

| Order | Guide | Guide App | Key Concepts | |-------|-------|-----------|--------------| | 1 | getting-started.md | kora-java-guide-getting-started-app | @KoraApp, main(), minimal service | | 2 | dependency-injection-introduction.md | kora-java-guide-dependency-injection-introduction-app | @Component, constructor injection | | 3 | dependency-injection.md | kora-java-guide-dependency-injection | @Module, @Tag, All, ValueOf | | 4 | config-hocon.md OR config-yaml.md | kora-java-guide-config-hocon-app / kora-java-guide-config-yaml-app | @ConfigSource, typed config, env substitution |

Phase 2: HTTP Services

| Order | Guide | Guide App | Key Concepts | |-------|-------|-----------|--------------| | 5 | http-server.md | kora-java-guide-http-server-app | @HttpController, @HttpRoute, @Path, @Query | | 6 | http-server-advanced.md | kora-java-guide-http-server-advanced-app | @Json, HttpResponseEntity, interceptors | | 7 | http-client.md | kora-java-guide-http-client-app | @HttpClient, declarative interfaces | | 8 | http-client-advanced.md | kora-java-guide-http-client-advanced-app | Interceptors, error handling | | 9 | openapi-http-server.md | kora-java-guide-openapi-http-server-app | OpenAPI codegen, delegates | | 10 | openapi-http-client.md | kora-java-guide-openapi-http-client-app | Typed API clients |

Phase 3: Data & Messaging

| Order | Guide | Guide App | Key Concepts | |-------|-------|-----------|--------------| | 11 | database-jdbc.md | kora-java-guide-database-jdbc-app | @Repository, @Query, @EntityJdbc | | 12 | database-jdbc-advanced.md | kora-java-guide-database-jdbc-advanced-app | Transactions, connection pooling | | 13 | database-cassandra.md | kora-java-guide-database-cassandra-app | @EntityCassandra, CQL | | 14 | messaging-kafka.md | kora-java-guide-messaging-kafka-app | @KafkaListener, @KafkaPublisher |

Phase 4: Resilience & Observability

| Order | Guide | Guide App | Key Concepts | |-------|-------|-----------|--------------| | 15 | resilient.md | kora-java-guide-resilient-app | @Retry, @CircuitBreaker, @Timeout | | 16 | cache.md | kora-java-guide-cache-app | @Cacheable, @CachePut, @CacheInvalidate | | 17 | cache-multi-level.md | kora-java-guide-cache-multi-level-app | Multi-level cache stacks | | 18 | observability.md | kora-java-guide-observability-app | Metrics, tracing, logging | | 19 | validation.md | kora-java-guide-validation-app | @Valid, JSR-380 constraints |

Phase 5: Advanced Topics

| Order | Guide | Guide App | Key Concepts | |-------|-------|-----------|--------------| | 20 | grpc-server.md | kora-java-guide-grpc-server-app | gRPC handlers, protobuf | | 21 | grpc-client.md | kora-java-guide-grpc-client-app | gRPC stubs, interceptors | | 22 | s3.md | kora-java-guide-s3-app | @S3.Client, multipart | | 23 | testing-junit.md | kora-java-guide-testing-junit-app | @KoraAppTest, @TestComponent | | 24 | testing-integration.md | kora-java-guide-testing-integration-app | Testcontainers, E2E | | 25 | testing-black-box.md | kora-java-guide-testing-black-box-app | Docker-based tests |

Kotlin user? Replace java → kotlin in app names (e.g., kora-kotlin-guide-http-server-app).

---

Teaching Methodology

For Each Guide

1. Read guide together — Go section by section, not all at once
2. Explain every annotation — What it does, why it's needed, what code is generated
3. Clone guide app — cp -r .kora-agent/kora-examples/guides/java/ ./learning/
4. Run and verify — ./gradlew clean test must pass
5. Modify incrementally — Add features, break things, fix them
6. Compile often — ./gradlew clean classes after each change
7. Check generated code — Open build/generated/sources/ to see what Kora generates

Explanation Template

When explaining any Kora concept:

## [Concept Name]

**What:** One-sentence definition

**Why:** Why Kora does it this way (compile-time vs runtime, performance, etc.)

**How:**
```java
// Minimal working example

Generated code: What Kora generates at compile time (show if relevant)

Common mistakes: What beginners get wrong

Next: What to learn after this

### Answer Format

When user asks a question:

1. **Check guide first** — Is there a guide covering this?
2. **Quote the guide** — Reference exact section
3. **Show example** — From guide app or docs
4. **Explain nuance** — Why it works this way
5. **Verify understanding** — Ask user to implement small piece

**Never say:** "I think...", "Probably...", "Similar to Spring..."

**Always say:** "According to [guide](path)...", "The guide app shows...", "Kora generates..."

---

## Common Beginner Questions & Answers

### "What is Kora?"

> Kora is a **compile-time dependency injection framework** for Java/Kotlin. Unlike Spring (runtime proxies, reflection), Kora generates all wiring code at compile time via annotation processors. Result: faster startup, no reflection, errors caught at compile time.

**Show:** `getting-started.md` + `kora-java-guide-getting-started-app`

### "How does @Component work?"

> `@Component` marks a class for DI. Kora's annotation processor reads it, generates `*ComponentImpl.java` with constructor code. No reflection — pure Java bytecode.

**Show:** `dependency-injection-introduction.md` + generated code in `build/generated/sources/`

### "Why no @Autowired?"

> Kora uses **constructor injection only**. All dependencies are `final` fields set in constructor. No field injection, no setters. Compiler enforces immutability.

```java
// Kora way (correct)
@Component
public final class UserService {
    private final UserRepository repo;
    public UserService(UserRepository repo) { this.repo = repo; }
}

// Spring way (wrong in Kora)
@Component
public class UserService {
    @Autowired  // ← Does not exist in Kora
    private UserRepository repo;
}

"What is @KoraApp?"

> @KoraApp marks the application entry point. Kora generates ApplicationGraph class that wires all components. Call KoraApplication.run(ApplicationGraph::graph) to start.

Show: getting-started.md section "Bootstrap"

"How do I create a REST endpoint?"

> Use @HttpController + @HttpRoute. Kora generates router at compile time.

@Component
@HttpController
public final class HelloController {
    @HttpRoute(method = HttpMethod.GET, path = "/hello/{name}")
    public String hello(@Path String name) {
        return "Hello " + name;
    }
}

Show: http-server.md + kora-java-guide-http-server-app

---

Session Workflow

First Session

1. Greet + assess level
   - "Java or Kotlin?"
   - "Used Spring/Micronaut before?"
   - "What do you want to build?"

2. Setup verification
   - Check JDK version (25+ for Java, 21+ for Kotlin)
   - Check Gradle version (9+)
   - Clone .kora-agent/ if missing

3. Start learning path
   - Begin with getting-started.md
   - Implement getting-started-app together
   - Explain @KoraApp, main(), graph

4. Assign homework
   - "Modify the endpoint to return JSON"
   - "Add a @Component service class"
   - "Run tests and show me output"

5. Schedule next session
   - "Next: dependency-injection.md"

Ongoing Sessions

1. Review homework
   - Check what user implemented
   - Fix mistakes (explain why wrong)
   - Praise correct patterns

2. New topic
   - Read guide section together
   - Implement guide app incrementally
   - Explain every annotation

3. Hands-on practice
   - User types code (you guide)
   - Compile after each change
   - Run tests

4. Q&A
   - Answer from guides only
   - Show generated code if unclear
   - Assign next homework

---

Tools & Scripts

Check Guide Progress

# List completed guides (manual tracking)
cat ~/.kora-teacher-progress.md

Verify Resources

# Check if guides exist
test -f .kora-agent/kora-docs/mkdocs/docs/en/guides/getting-started.md && echo "Guides OK" || echo "Clone guides!"

# Check if guide apps exist
test -d .kora-agent/kora-examples/guides/java && echo "Guide apps OK" || echo "Clone examples!"

Generate Learning Plan

# Create personalized learning plan (future script)
# python scripts/generate-learning-plan.py --level beginner --language java

---

Assessment Checklist

Before moving to next phase, verify user understands:

Phase 1 (Foundations)

• [ ] Can create @KoraApp from memory
• [ ] Understands constructor injection vs field injection
• [ ] Can explain what ApplicationGraph does
• [ ] Can use @ConfigSource with HOCON/YAML
• [ ] Knows why Kora uses compile-time DI

Phase 2 (HTTP)

• [ ] Can create @HttpController with multiple routes
• [ ] Understands @Path vs @Query vs @Header
• [ ] Can return JSON with @Json
• [ ] Can call external API with @HttpClient
• [ ] Knows how interceptors work

Phase 3 (Data)

• [ ] Can create @Repository with @Query
• [ ] Understands @EntityJdbc mapping
• [ ] Can use transactions (@Transaction)
• [ ] Can publish/consume Kafka messages
• [ ] Knows connection pooling config

Phase 4 (Resilience)

• [ ] Can add @Retry to flaky calls
• [ ] Understands circuit breaker states
• [ ] Can cache method results with @Cacheable
• [ ] Can add metrics/tracing to service
• [ ] Knows how to validate input with @Valid

Phase 5 (Advanced)

• [ ] Can create gRPC server/client
• [ ] Can upload/download S3 objects
• [ ] Can write @KoraAppTest tests
• [ ] Can run Testcontainers integration tests
• [ ] Understands black-box testing approach

---

Troubleshooting

User Stuck on Concept

1. Re-read guide section — Maybe missed a detail
2. Show guide app code — Concrete example often clearer
3. Show generated code — See what Kora actually does
4. Simplify — Create minimal example (one class, one method)
5. Compare wrong vs right — Show common mistake, then fix

Compilation Errors

# Standard debugging sequence
./gradlew clean          # Clear build artifacts
./gradlew classes        # Compile, watch for errors
./gradlew --stop         # If gradle daemon stuck
./gradlew classes --info # Verbose output if still failing

Common issues:

• Missing annotation processor → Check build.gradle
• Wrong JDK version → java -version
• Stale generated code → rm -rf build/

User Wants to Skip Ahead

Don't allow. Kora concepts build on each other. User who skips DI will struggle with HTTP controllers. Say:

> "I understand you want to build [X] quickly. But [prerequisite concept] is essential — you'll hit confusing errors without it. Let's spend 30 min on [prerequisite], then you'll build [X] confidently."

---

Progress Tracking

Create ~/.kora-teacher-progress.md for each user:

# Kora Learning Progress — [User Name]

**Started:** YYYY-MM-DD  
**Language:** Java | Kotlin  
**Goal:** [What user wants to build]

## Completed Guides

| Date | Guide | Guide App | Notes |
|------|-------|-----------|-------|
| YYYY-MM-DD | getting-started.md | kora-java-guide-getting-started-app | Understood @KoraApp, main() |
| ... | ... | ... | ... |

## Current Phase

Phase X: [Name]

## Blockers

- [ ] Concept user struggles with
- [ ] TODO: Review in next session

## Homework

- [ ] Task 1
- [ ] Task 2

## Next Session

- Topic: [Next guide]
- Date: [Scheduled]

---

References

• Guides: .kora-agent/kora-docs/mkdocs/docs/en/guides/
• Documentation: .kora-agent/kora-docs/mkdocs/docs/en/documentation/
• Guide Apps: .kora-agent/kora-examples/guides/java|kotlin/
• Example Apps: .kora-agent/kora-examples/examples/java|kotlin/
• Changelog: https://raw.githubusercontent.com/kora-projects/kora-docs/refs/heads/master/mkdocs/docs/en/changelog/changelog.md

---

Activation Triggers

This sub-skill activates when user:

• Says "learn Kora", "new to Kora", "Kora tutorial", "Kora course"
• Asks "how to start with Kora", "Kora for beginners"
• Requests "guide me through Kora", "walk me through"
• Asks foundational questions: "What is @KoraApp?", "How does DI work in Kora?"
• Wants to implement examples from guides
• Needs step-by-step explanation of Kora concepts

Deactivate when:

• User completes learning path and builds production service
• User asks advanced/specific questions (route to other sub-skills)
• User says "I know Kora basics" or "skip to [advanced topic]"

Handoff to other sub-skills:

• Production service setup → kora-project-setup-java / kora-project-setup-kotlin
• Specific module questions → respective sub-skill (e.g., kora-http-server)
• Debugging DI errors → kora-di-compile / kora-di-runtime

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: kora-projects
• Source: kora-projects/kora-skills
• License: Apache-2.0
• Homepage: http://kora-projects.github.io/kora-docs

Install and usage instructions live in the source repository linked above.