A follow-up in my Harness plugin was resetting the agent's tools

I maintain ThoughtDAG, a conversation map plugin for DeepSeek Harness. A user found that asking a follow-up from the map could reset their agent preset's tool state.

hexu321 traced it to session handling: the next node was starting a fresh session, so the preset lost the state it had built up.

The fix handles two cases:

- Continue from the latest turn: keep the same session.

- Branch from an earlier turn: fork at that exact turn, leaving later messages from the other branch out.

We checked both paths against a live Harness session on macOS. This fix covers single-parent continuation and branching. It shipped in 0.4.12.

Thanks to hexu321 for the logs, diagnosis and fix. The PR includes the reproduction and verification:

https://github.com/chenxiachan/thoughtdag/pull/29

For others building on Harness: how do you handle stateful agent presets when a user branches from an earlier turn?