The first way we noticed it was not from a crash. The build still passed, the repo state looked normal, but when we ran the app, part of the feature was just missing.
After that, we started comparing what each agent said it had completed against what actually survived in the repo. That made the failure obvious: an agent would report success, but a later valid write had overwritten the same surface.
We then tested it more directly with 5 Claude Code agents on the same Express.js repo. In the concurrent run, about 24% of intended changes disappeared while the build still passed, and one agent’s auth routes were completely lost.
So I think this lines up with @wfh distinction above: LangGraph state/reducers give you a safety model inside the graph, but once agents mutate external shared resources like repo files, you’re back in plain read-modify-write territory.
Orchestration and scoped tasks help reduce overlap, but they don’t fully solve that boundary if two workers can still touch the same shared surface. That’s what pushed us toward Klock: pre-write coordination for cooperative file-mutating agents. Not as a replacement for LangGraph state, but as a separate layer for shared resources outside the graph.
Important limitation: OSS v1 is still narrow. It works for cooperative agents that call the SDK or wrapped tools before mutation. It’s not transparent filesystem-level enforcement yet.