Koog Files

Published 17 March 2026

Major Features

• Java API: Introduced comprehensive Java interoperability across the framework:
• Java API for creating and running agents from pure Java projects (#1185)
• Builder-based Java API for graph strategies (#1581, [#1617], [#1366])
• Java-friendly API for AIAgentStorage with JVM-specific methods (#1600)
• Blocking API builders for PromptExecutor and LLMClient for Java (#1555, [#1604])
• Jackson as the default serializer for Java API (#1630)
• Weave and Langfuse integrations now available from Java (#1616)
• Centralized Java/Kotlin time conversion utilities (TimeUtils, toKotlinDuration, etc.) (#1620)
• Spring AI Integration: Added two new Spring Boot starters (koog-spring-ai-starter-model-chat and koog-spring-ai-starter-model-embedding) to integrate Spring AI ChatModel and EmbeddingModel implementations as Koog LLM backends, enabling support for the wide range of providers available in Spring AI (KG-109, [#1587])
• Chat Memory: Introduced persistent chat memory with multiple storage backend options:
  • Core ChatMemory feature and ChatHistoryProvider abstraction (#1511)
  • Exposed-ORM based providers for PostgreSQL, MySQL, and H2 (#1584)
  • Pure JDBC ChatHistoryProvider for PostgreSQL, MySQL, and H2 with no ORM dependency (#1597)
  • JDBC-based PersistenceStorageProvider (#1612)
• Long-term Memory: Added LongTermMemory feature that augments prompts with relevant memory records from storage and extracts/ingests new memories from agent conversations (#1490)
• Library-Agnostic Serialization API: Introduced a JSONSerializer abstraction to support pluggable serialization libraries. Two implementations provided: KotlinxSerializer (default) and the new JacksonSerializer in a separate serialization-jackson module. Tools API migrated to this new abstraction (#1588)

Improvements

• OpenTelemetry:
• Added OpenTelemetry support for functional agent pipelines (KG-677, [#1447])
• Added OpenTelemetry spans for MCP tool calls (#1421)
• Planner improvements:
• Added AIAgentPlannerContext and AIAgentFunctionalContextBase for better context hierarchy and planner-specific APIs (#1480)
• Added planner-specific pipeline interceptors: onPlanCreationStarting/Completed, onStepExecutionStarting/Completed, onPlanCompletionEvaluationStarting/Completed (KG-672, [#1550])
• GOAP strategies now have typed input/output and a dedicated GoapAgentState (#1498)
• OpenRouter embedding support: Implemented LLMEmbeddingProvider for OpenRouter, enabling access to 21+ embedding models (KG-659, [#1398])
• Swift Package Manager support: Added XCFramework build and distribution infrastructure for iOS/macOS development via SPM (KG-682, [#1485])

New LLM Models

• Anthropic Claude Opus 4.6: Added support via Anthropic and Bedrock executors (#1513)
• Google Gemini 3 Flash Preview: New model with extended capabilities and high-speed processing (#1621)
• OpenAI GPT-5.x series: Added GPT-5.1-Codex-Max, GPT-5.2-Codex, GPT-5.3-Codex, GPT-5.4, and GPT-5.4-Pro (#1595)
• Moonshot Kimi K2 Thinking: Added support via the Bedrock Converse API (#1436)
• Ollama thinking support: Added think=true request parameter and streaming reasoning delta support for Ollama models (#1532)

Bug Fixes

• Persistence checkpoints: Fixed last successful node being re-executed when restoring from a checkpoint; changed lastInput to lastOutput in checkpoint structure (#1308)
• Ollama streaming: Fixed Ollama client to use preparePost(...).execute for proper streaming instead of buffering the full response (#1497)
• OpenRouter streaming: Fixed missing reasoning and reasoningDetails fields in OpenRouterStreamDelta causing deserialization errors (#1504)
• Dashscope streaming: Fixed tool call argument merging for streaming responses in DashscopeLLMClient (KG-658, [#1590])
• agents-ext dependency leak: Moved agents-ext from commonMain api to jvmTest implementation in agents-test to prevent transitive compile-time dependency leakage (#1506)
• Streaming exception handling: executeStreaming now properly propagates exceptions from LLM clients and requires StreamFrame.End to signal stream completion (KG-550, [#1580])
• Debugger feature: Extended to support functional agents in addition to graph-based agents by dispatching appropriate strategy starting events (KG-741, [#1637])

Breaking Changes

• Serialization API: All encode/decode methods in Tool now accept a second JSONSerializer parameter. Automatic ToolDescriptor generation for primitive argument types (Tool<String, String>) is no longer supported without a custom descriptor. AIAgentFeature.createInitialConfig now takes an agentConfig: AIAgentConfig parameter. JSON types in pipeline events changed from kotlinx.serialization to ai.koog.serialization (#1588)
• TypeToken replaces KType: Nodes and agent features now work with ai.koog.serialization.TypeToken instead of kotlin.reflect.KType. All typeOf<Foo>() usages should be replaced with typeToken<Foo>() (#1581)
• Global JSON schema registries removed: RegisteredStandardJsonSchemaGenerators and RegisteredBasicJsonSchemaGenerators removed. getStructuredRequest and StructureFixingParser moved to ai.koog.prompt.executor.model package (KG-698, [#1517])
• LLMDescription.description renamed to value: The description field of LLMDescription has been renamed to value for Java compatibility (#1607)
• Deprecated kotlinx.datetime imports replaced with kotlin.time equivalents (Clock, Instant) (#1533)
• Retired Anthropic/Bedrock models: Removed Sonnet_3_7, Haiku_3_5, Sonnet_3_5, and Opus_3 from Anthropic models; removed several AI21, Bedrock, and legacy Anthropic models. Haiku_3 marked as deprecated (#1526)

Documentation

• Added documentation for Java API and Java examples (#1610)
• Added documentation for Spring AI integration (KG-109, [#1627])
• Added documentation for custom feature creation (#1295)
• Reworked Getting Started, agent types, and Chat Memory tutorials (#1349, [#1552])
• Improved Prompts and Planner agent documentation (#1302, [#1301])
• Added nightly builds documentation (#1433)

Examples

• Added Java example for JavaOne 2026 (#1641)
• Added full Spring Boot Java API example (#1350)
• Added example for calling a Koog agent from JavaScript code, including browser (TypeScript webapp) and Node.js usage with AbortSignal support (#1500)