JetBrains/koog 0.6.0

on GitHub

Published 22 December 2025

Major Features

• ACP Integration: Introduce initial ACP (Agent Communication Protocol) integration to create ACP-compatible agents in Koog (#1253)
• Planner Agent Type: Introduce new "planner" agent type with iterative planning capabilities. Provide two out-of-the box strategies: simple LLM planner and GOAP (Goal-Oriented Action Planning) (#1232)
• Response Processor: Introduce ResponseProcessor to fix tool call messages from weak models that fail to properly generate tool calls (KG-212, #871)

Improvements

• Event ID Propagation: Integrate event ID and execution info propagation across all pipeline events, agent execution flow, and features including Debugger and Tracing (KG-178)
• Bedrock Enhancements:
  • Add fallback model support and warning mechanism for unsupported Bedrock models with custom families (KG-595, #1224)
  • Add global inference profile prefix support to Bedrock models for improved availability and latency (#1139)
  • Add Bedrock support in Ktor integration for configuring and initializing Bedrock LLM clients (#1141)
  • Improve Bedrock moderation implementation with conditional guardrails API calls (#1105)
• Ollama: Add support for file attachments in Ollama client (#1221)
• Tool Schema: Add extension point for custom tool schemas to allow clients to provide custom schemas or modify existing ones (#1158)
• Google Client:
  • Add support for /models request in Google LLM Client (#1181)
  • Add text embedding support for Google's Gemini models via gemini-embedding-001 (KG-314, #1235)
• HTTP Client: Make KoogHttpClient auto-closable and add clientName parameter (#1184)
• Update MCP SDK version to 0.7.7 (#1154)
• Use SEQUENTIAL mode as default for singleRunStrategy (#1195)

Bug Fixes

• Streaming: Fix streaming + tool call issues for Google and OpenRouter clients - Google client now passes tools parameter, OpenRouter uses CIO engine for SSE, improved SSE error handling (KG-616, #1262)
• Tool Calling: Fix requestLLMOnlyCallingTools ignoring tool calls after reasoning messages from models with Chain of Thought (KG-545, #1198)
• File Tools:
  • Handle empty filters in ListDirectoryTool (KG-628, #1285)
  • Fix directory collapse in ListDirectoryUtil (KG-583, #1260)
  • Clamp endLine to file length and add warnings for overflow in ReadFileTool (KG-534, #1182)
• Model-Specific Fixes:
  • Pass jsonObject as responseFormat for DeepSeek to fix JSON mode (KG-537, #1258)
  • Remove LLMCapability.Temperature from GPT-5 model capabilities (#1277)
  • Fix OpenAI streaming with tools in Responses API (KG-584, #1255)
  • Fix Bedrock timeout setting propagation to BedrockRuntimeClient.HttpClient (#1190)
  • Add handler for GooglePart.InlineData to support binary content responses (KG-487, #1094)
• Other Fixes:
  • Fix reasoning message handling in provided simple strategies (#1166)
  • Fix empty list condition check in onMultipleToolResults and onMultipleAssistantMessages (#1192)
  • Fix timeout not respected in executor because join() was called before timeout check (#1005)
  • Fix ContentPartsBuilder to flush whenever textBuilder is not empty (KG-504, #1123)
  • Fix and simplify McpTool to properly support updated Tool serialization (#1128)
  • Fix OpenAIConfig.moderationsPath to be mutable (var instead of val) (#1097)
  • Finalize pipeline feature processors after agent run for StatefulSingleUseAIAgent (KG-576)

Breaking Changes

• Persistence: Remove requirement for unique graph node names in Persistence feature, migrate to node path usage (#1288)
• Tool API: Update Tool API to fix name and descriptor discrepancy - moved configurable tool properties to constructors, removed doExecute in favor of execute (KG-508, #1226)
• OpenAI Models: GPT-5-Codex and GPT-5.1 reasoning models moved from Chat section to Reasoning section (KG-562, #1146)
• Structured Output: Rename structured output classes - StructuredOutput → StructuredRequest, StructuredData → Structure, JsonStructuredData → JsonStructure (#1107)
• Module Organization: Move LLMChoice from prompt-llm to prompt-executor-model module (#1109)