JetBrains/koog 0.6.1

on GitHub

Published 28 January 2026

Major Features

Block of changes:

• Converse API support in Bedrock LLM client: Added support for the Converse API in the Bedrock LLM client, enabling richer prompt-based interactions (KG-543, #1384)
• Tool choice heuristics: Introduced heuristic-based required tool selection via LLMBasedToolCallFixProcessor for models that do not support explicit tool choice (KG-200, #1389)

Improvements

• Prompt parameter preservation: Ensured that LLMParams fields are preserved after calling Prompt.withUpdatedParams (#1194)
• Error handling for tools: Improved error handling for tool argument parsing, result serialization, and subgraph tool execution failures (KG-597, #1329)
• OpenTelemetry:
  • Updated span attributes and names to better align with semantic conventions (KG-646, #1351; KG-647, #1359)
  • Replaced agent data propagation through the coroutine context with the AIAgentContext instance for agent events (KG-178, #1336)
• ACP SDK update: Updated the ACP SDK to version 0.13.1 to enable connections from IntelliJ-based IDE clients (KG-671, #1363)

Bug fixes

• OpenAI client:
  • Restored the minimal option in ReasonEffort within OpenAIDataModels (#1412)
  • Fixed missing token usage information in streaming mode (#1072, #1404)
• Bedrock client:
  • Fixed JSON schema generation for Bedrock tools to correctly handle nested objects (#1259, #1361)
  • Fixed parsing of tool usage in Bedrock Anthropic streaming responses (KG-627, #1310)
• DeepSeek structured output: Fixed structured output handling for DeepSeek (KG-537, #1385)
• Gemini 3.0 tool calls: Fixed thought signature handling for tool calls (KG-596, #1317)
• Subtask completion flow: Ensured that subtasks return after a tool call finishes, before issuing a new LLM request (#1322, #1362)

Examples

• Updated the ACP example to use the latest ACP SDK version (#1363)
• Updated the Compose Demo App to use the latest Koog version (#1227)