When small models break tool-call JSON
rust
dev.to
A coding agent lives and dies by tool calls. With a frontier model you barely think about them. With a 7B model running on your laptop, the JSON is where things fall apart. This is what we ran into in oxi, what is safe to fix on the client, and why everything else should go back to the model instead of being hidden. How a tool call gets to your code In an OpenAI-compatible API, the model doesn't run anything. It returns a message with a tool_calls array: a tool name and an arguments