tessl/maven-com-embabel-agent--embabel-agent-common

Common AI framework utilities for the Embabel Agent system including LLM configuration, output converters, prompt contributors, and embedding service abstractions.

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Integration Patterns

Name: tessl/maven-com-embabel-agent--embabel-agent-common
Author: tessl

Common patterns for integrating Embabel Agent Common with Spring, reactive streams, and LLM clients.

Spring Integration

Configuration Beans

import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import com.fasterxml.jackson.databind.ObjectMapper

@Configuration
class AIConfiguration {
    @Bean
    fun objectMapper(): ObjectMapper {
        return ObjectMapper()
            .registerKotlinModule()
            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
    }

    @Bean
    fun defaultLlmOptions(): LlmOptions {
        return LlmOptions.withModel("gpt-4")
            .withTemperature(0.7)
            .withMaxTokens(1000)
    }

    @Bean
    fun embeddingService(embeddingModel: EmbeddingModel): EmbeddingService {
        return SpringAiEmbeddingService(
            name = "text-embedding-ada-002",
            provider = "openai",
            model = embeddingModel
        )
    }
}

Service Layer

import org.springframework.stereotype.Service

@Service
class LLMService(
    private val chatClient: ChatClient,
    private val objectMapper: ObjectMapper
) {
    fun <T> callWithStructuredOutput(
        prompt: String,
        responseType: Class<T>,
        options: LlmOptions = LlmOptions.withDefaultLlm()
    ): T? {
        val converter = JacksonOutputConverter(responseType, objectMapper)

        val fullPrompt = """
            $prompt

            ${converter.getFormat()}
        """.trimIndent()

        val response = chatClient
            .prompt()
            .user(fullPrompt)
            .call()
            .content()

        return converter.convert(response)
    }
}

Prompt Contributors as Beans

@Component
class SystemPromptContributor : PromptContributor {
    override val role = "system"
    override val promptContributionLocation = PromptContributionLocation.BEGINNING

    override fun contribution(): String {
        return "You are a helpful AI assistant."
    }
}

@Service
class PromptService(
    private val contributors: List<PromptContributor>
) {
    fun buildPrompt(userInput: String): String {
        val beginning = contributors
            .filter { it.promptContributionLocation == PromptContributionLocation.BEGINNING }
            .joinToString("\n\n") { it.contribution() }

        val end = contributors
            .filter { it.promptContributionLocation == PromptContributionLocation.END }
            .joinToString("\n\n") { it.contribution() }

        return buildString {
            if (beginning.isNotEmpty()) {
                appendLine(beginning)
                appendLine()
            }
            appendLine(userInput)
            if (end.isNotEmpty()) {
                appendLine()
                appendLine(end)
            }
        }.trim()
    }
}

Structured Output Pattern

Complete pattern for LLM calls with typed responses.

data class ExtractedData(
    val entities: List<String>,
    val sentiment: String,
    val summary: String
)

@Service
class ExtractionService(
    private val chatClient: ChatClient,
    private val objectMapper: ObjectMapper,
    private val costTracker: CostTracker
) {
    fun extractData(text: String): ExtractedData? {
        val converter = JacksonOutputConverter(ExtractedData::class.java, objectMapper)

        val prompt = """
            Extract information from the following text.

            ${converter.getFormat()}

            Text: $text
        """.trimIndent()

        val options = LlmOptions.withModel("gpt-4")
            .withTemperature(0.3)
            .withMaxTokens(500)

        val response = chatClient
            .prompt()
            .user(prompt)
            .call()
            .content()

        // Track costs
        val usage = response.metadata?.usage
        if (usage != null) {
            costTracker.recordUsage(usage)
        }

        return converter.convert(response)
    }
}

Streaming Pattern

Process streaming LLM responses reactively.

@Service
class StreamingService(
    private val chatClient: ChatClient,
    private val objectMapper: ObjectMapper
) {
    fun streamEvents(prompt: String): Flux<Event> {
        val converter = StreamingJacksonOutputConverter(
            Event::class.java,
            objectMapper
        )

        val fullPrompt = """
            $prompt

            ${converter.getFormat()}
        """.trimIndent()

        return chatClient
            .prompt()
            .user(fullPrompt)
            .stream()
            .content()
            .buffer()
            .map { chunks -> chunks.joinToString("") }
            .flatMapMany { jsonl -> converter.convertStream(jsonl) }
    }

    fun streamWithThinking(prompt: String): Flux<StreamingEvent<Event>> {
        val converter = StreamingJacksonOutputConverter(
            Event::class.java,
            objectMapper
        )

        return chatClient
            .prompt()
            .user(prompt)
            .stream()
            .content()
            .buffer()
            .map { it.joinToString("") }
            .flatMapMany { converter.convertStreamWithThinking(it) }
    }
}

Cost Tracking Pattern

Track costs across requests and sessions.

@Service
class ManagedLLMService(
    private val chatClient: ChatClient,
    private val pricing: PricingModel
) {
    private val sessionTracker = CostTracker(pricing)

    fun callWithTracking(prompt: String, options: LlmOptions): String {
        val response = chatClient
            .prompt()
            .user(prompt)
            .call()

        val usage = response.metadata?.usage
        if (usage != null) {
            sessionTracker.recordUsage(usage)
            logger.info("Request cost: $${pricing.costOf(usage)}")
            logger.info("Session total: $${sessionTracker.totalCost()}")
        }

        return response.content()
    }

    fun getSessionCost(): Double = sessionTracker.totalCost()

    fun resetSession() {
        sessionTracker.reset()
    }
}

Multi-Model Pattern

Route requests to different models based on criteria.

@Service
class MultiModelService(
    private val chatClient: ChatClient,
    private val objectMapper: ObjectMapper
) {
    private val modelStrategy = mapOf(
        "quick" to LlmOptions.withModel("gpt-3.5-turbo").withMaxTokens(500),
        "balanced" to LlmOptions.withModel("gpt-4").withMaxTokens(1000),
        "creative" to LlmOptions.withModel("claude-3-opus").withTemperature(0.9),
        "analytical" to LlmOptions.withModel("gpt-4").withTemperature(0.2)
    )

    fun call(prompt: String, strategy: String = "balanced"): String {
        val options = modelStrategy[strategy]
            ?: throw IllegalArgumentException("Unknown strategy: $strategy")

        return chatClient
            .prompt()
            .user(prompt)
            .call()
            .content()
    }

    fun <T> callStructured(
        prompt: String,
        responseType: Class<T>,
        strategy: String = "balanced"
    ): T? {
        val converter = JacksonOutputConverter(responseType, objectMapper)
        val options = modelStrategy[strategy]
            ?: throw IllegalArgumentException("Unknown strategy: $strategy")

        val fullPrompt = "$prompt\n\n${converter.getFormat()}"
        val response = call(fullPrompt, strategy)

        return converter.convert(response)
    }
}

Embedding Pattern

Semantic search and similarity detection.

@Service
class SemanticSearchService(
    private val embeddingService: EmbeddingService
) {
    private val documents = mutableListOf<Pair<String, FloatArray>>()

    fun indexDocument(text: String) {
        val embedding = embeddingService.embed(text)
        documents.add(text to embedding)
    }

    fun indexDocuments(texts: List<String>) {
        val embeddings = embeddingService.embed(texts)
        texts.zip(embeddings).forEach { (text, embedding) ->
            documents.add(text to embedding)
        }
    }

    fun search(query: String, topK: Int = 5): List<String> {
        val queryEmbedding = embeddingService.embed(query)

        return documents
            .map { (text, embedding) ->
                text to cosineSimilarity(queryEmbedding, embedding)
            }
            .sortedByDescending { it.second }
            .take(topK)
            .map { it.first }
    }

    fun findSimilar(text: String, threshold: Double = 0.7): List<String> {
        val embedding = embeddingService.embed(text)

        return documents
            .filter { (_, docEmbedding) ->
                cosineSimilarity(embedding, docEmbedding) >= threshold
            }
            .map { it.first }
    }

    private fun cosineSimilarity(a: FloatArray, b: FloatArray): Double {
        val dotProduct = a.zip(b).sumOf { (x, y) -> (x * y).toDouble() }
        val magA = kotlin.math.sqrt(a.sumOf { (it * it).toDouble() })
        val magB = kotlin.math.sqrt(b.sumOf { (it * it).toDouble() })
        return dotProduct / (magA * magB)
    }
}

RAG Pattern

Retrieval-Augmented Generation with embeddings.

@Service
class RAGService(
    private val embeddingService: EmbeddingService,
    private val chatClient: ChatClient
) {
    private val knowledgeBase = mutableListOf<Pair<String, FloatArray>>()

    fun addKnowledge(text: String) {
        val embedding = embeddingService.embed(text)
        knowledgeBase.add(text to embedding)
    }

    fun addKnowledge(texts: List<String>) {
        val embeddings = embeddingService.embed(texts)
        texts.zip(embeddings).forEach { (text, embedding) ->
            knowledgeBase.add(text to embedding)
        }
    }

    fun query(question: String, topK: Int = 3): String {
        // 1. Embed question
        val questionEmbedding = embeddingService.embed(question)

        // 2. Find relevant context
        val relevantDocs = knowledgeBase
            .map { (text, embedding) ->
                text to cosineSimilarity(questionEmbedding, embedding)
            }
            .sortedByDescending { it.second }
            .take(topK)
            .map { it.first }

        // 3. Build prompt with context
        val context = relevantDocs.joinToString("\n\n")
        val prompt = """
            Use the following context to answer the question.

            Context:
            $context

            Question: $question

            Answer:
        """.trimIndent()

        // 4. Generate answer
        return chatClient
            .prompt()
            .user(prompt)
            .call()
            .content()
    }

    private fun cosineSimilarity(a: FloatArray, b: FloatArray): Double {
        val dotProduct = a.zip(b).sumOf { (x, y) -> (x * y).toDouble() }
        val magA = kotlin.math.sqrt(a.sumOf { (it * it).toDouble() })
        val magB = kotlin.math.sqrt(b.sumOf { (it * it).toDouble() })
        return dotProduct / (magA * magB)
    }
}

Batch Processing Pattern

Process multiple requests efficiently.

@Service
class BatchProcessingService(
    private val chatClient: ChatClient,
    private val objectMapper: ObjectMapper
) {
    fun <T> processBatch(
        items: List<String>,
        responseType: Class<T>,
        batchSize: Int = 10
    ): List<T?> {
        val converter = JacksonOutputConverter(responseType, objectMapper)

        return items.chunked(batchSize).flatMap { batch ->
            batch.mapNotNull { item ->
                val prompt = "Process: $item\n\n${converter.getFormat()}"
                val response = chatClient
                    .prompt()
                    .user(prompt)
                    .call()
                    .content()

                converter.convert(response)
            }
        }
    }

    fun <T> processBatchParallel(
        items: List<String>,
        responseType: Class<T>
    ): Flux<T> {
        val converter = JacksonOutputConverter(responseType, objectMapper)

        return Flux.fromIterable(items)
            .parallel()
            .runOn(Schedulers.parallel())
            .flatMap { item ->
                val prompt = "Process: $item\n\n${converter.getFormat()}"
                Mono.fromCallable {
                    val response = chatClient
                        .prompt()
                        .user(prompt)
                        .call()
                        .content()

                    converter.convert(response)
                }
            }
            .sequential()
            .filter { it != null }
            .map { it!! }
    }
}

Retry Pattern with Backoff

@Service
class ResilientLLMService(
    private val chatClient: ChatClient
) {
    fun callWithRetry(
        prompt: String,
        maxRetries: Int = 3
    ): String? {
        var lastError: Exception? = null

        repeat(maxRetries) { attempt ->
            try {
                return chatClient
                    .prompt()
                    .user(prompt)
                    .call()
                    .content()
            } catch (e: Exception) {
                lastError = e
                logger.warn("Attempt ${attempt + 1} failed: ${e.message}")

                if (attempt < maxRetries - 1) {
                    val delay = 1000L * (attempt + 1) // Exponential backoff
                    Thread.sleep(delay)
                }
            }
        }

        logger.error("All retries failed", lastError)
        return null
    }

    fun callWithReactiveRetry(prompt: String): Mono<String> {
        return Mono.fromCallable {
            chatClient
                .prompt()
                .user(prompt)
                .call()
                .content()
        }
        .retryWhen(Retry.backoff(3, Duration.ofSeconds(1)))
        .onErrorResume { error ->
            logger.error("All retries failed", error)
            Mono.empty()
        }
    }
}

Caching Pattern

@Service
class CachedLLMService(
    private val chatClient: ChatClient
) {
    private val cache = ConcurrentHashMap<String, String>()

    fun callWithCache(prompt: String): String {
        return cache.getOrPut(prompt) {
            chatClient
                .prompt()
                .user(prompt)
                .call()
                .content()
        }
    }

    fun callWithTimedCache(
        prompt: String,
        ttl: Duration = Duration.ofMinutes(10)
    ): String {
        val cacheKey = "$prompt:${System.currentTimeMillis() / ttl.toMillis()}"
        return cache.getOrPut(cacheKey) {
            chatClient
                .prompt()
                .user(prompt)
                .call()
                .content()
        }
    }

    fun clearCache() {
        cache.clear()
    }
}

Testing Patterns

Mock Converters

class MockConverter<T>(private val mockResult: T) : StructuredOutputConverter<T> {
    override fun convert(text: String): T = mockResult
    override fun getFormat(): String = "Mock format"
}

@Test
fun `test service with mock converter`() {
    val mockPerson = Person("Test", 30, "test@example.com")
    val mockConverter = MockConverter(mockPerson)

    // Use in tests
    val result = service.process(mockConverter)
    assertEquals(mockPerson, result)
}

Integration Tests

@SpringBootTest
class LLMServiceIntegrationTest {
    @Autowired
    private lateinit var llmService: LLMService

    @Test
    fun `test structured output extraction`() {
        val result = llmService.callWithStructuredOutput(
            "Extract: John Doe, 30, john@example.com",
            Person::class.java
        )

        assertNotNull(result)
        assertEquals("John Doe", result?.name)
        assertEquals(30, result?.age)
    }
}

Best Practices

Use dependency injection for all services
Reuse ObjectMapper instances - they're thread-safe
Track costs in production environments
Implement retries with exponential backoff
Cache responses when appropriate
Use streaming for long-running tasks
Batch requests when possible
Handle errors gracefully with fallbacks
Test with mocks for unit tests
Monitor performance and costs in production

Install with Tessl CLI

npx tessl i tessl/maven-com-embabel-agent--embabel-agent-common@0.3.0

docs

advanced

error-handling.md

integration-patterns.md

performance.md

core

reference

supporting

tessl/maven-com-embabel-agent--embabel-agent-common