Open-Source Function-Calling Models in Production: Comparing Gorilla OpenFunctions-v2, Hermes 3, Functionary, and xLAM
Deploying autonomous AI agents and automated API workflows requires reliable structured output generation and tool invocation. While general-purpose language models can be prompted to output JSON tool invocations, specialized function-calling fine-tunes provide higher schema compliance, lower parameter hallucination rates, and support for parallel tool invocation. Four open-source model families have emerged as prominent architectures for local and private function calling: Gorilla OpenFunction
