fix: detect and correct text-based tool call hallucinations (MODEL_NO_TOOLS_USED loop)#5377
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kevinvandijk merged 3 commits intoKilo-Org:mainfrom Feb 13, 2026
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…t MODEL_NO_TOOLS_USED loop This fixes a common error loop where the model outputs '[Tool Use: ...]' as text instead of using the native API. The task loop now detects this pattern and issues a specific correction. Also updated system prompt guidelines.
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This was referenced Feb 13, 2026
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This PR addresses the recurring
MODEL_NO_TOOLS_USEDerror where models output tool calls as text (e.g.,[Tool Use: ...]) instead of using the native API format.Fixes #5256
Fixes #5280
Changes
src/core/task/Task.tsto detect text blocks matching the[Tool Use: ...]pattern. When detected, the system now provides a specific error message instructing the model to use the native tool calling capability. This immediate feedback breaks the retry loop.src/core/prompts/sections/tool-use-guidelines.tsto include a critical guideline for native protocol sessions, explicitly forbidding text-based tool call mimicry.This resolves the "mimicry loop" issues reported by users, particularly with Gemini and OpenRouter models.