Working Notes on Agent Systems/Brad Zhang

@teach_fireworks / X longform

This DeltaBox solves the sandbox state rollback problem of Stateful AI Agent. Agents wi...

This DeltaBox solves the sandbox state rollback problem of Stateful AI Agent. Agents will continuously change the file system, process status, tool status, and environment varia...

May 25, 2026 · 1 min read

This DeltaBox solves the sandbox state rollback problem of Stateful AI Agent.

Agents will continuously change the file system, process status, tool status, and environment variables during long tasks, code modifications, and branch explorations.

Traditional full-copy checkpoints are very costly.

The core idea of ​​DeltaBox is to only record the delta state between adjacent checkpoints, similar to git diff, rather than completely copying the sandbox.

In this way, the Agent can quickly save the state, roll back to historical nodes, and re-explore another path.

The paper results show that DeltaBox checkpoint is about 14ms and rollback is about 5ms, which is significantly faster than full copy and CRIU.

Its value lies in reducing Agent trial and error costs and making long task exploration, replay, and branch search more feasible.

When I read the DeltaBox paper today, I felt something very obvious.

Many Agents have begun to look different from traditional LLMs.

It used to be more like: input question → output answer.

The execution process of many agents now is actually closer: try, roll back, change paths, and try again.

This is especially obvious in long tasks.

Modify files, adjust tools, run programs, measure results...

the status will keep changing.

Once a certain step is missed, the entire link will start to drift.

Paper address:

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This DeltaBox solves the sandbox state rollback problem of Stateful AI Agent. Agents...THESISThis DeltaBox solvesthe sandbox staterollback problem ofStateful AI Agent.SIGNALThis DeltaBox solvesthe sandbox staterollback problem ofStateful AI Agent.OPERATORMany Agents have begunto look different fromtraditional LLMs.IMPLICATIONPaper address:
Mermaid outline
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