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Research paperSafety & Alignment · Reinforcement Learning1 source · Oct 6, 2026

RippleCP: Measuring Counterfactual Checkpoint Advantage in Coding Agents

Agent checkpoint systems decide what state is recovery-relevant, how to snapshot it, and whether rollback is admissible.

Key points

  • None decides which of the safe boundaries they expose are worth materializing.
  • We formulate this as counterfactual checkpoint advantage, the reduction in future recovery cost obtained by checkpointing a candidate rather than skipping it, and measure it by driving a CP branch and a SKIP branch to the same logical failure and recovering both under matched model, tool, verifier, and stopping conditions.
  • On a frozen pilot of 12 SWE-bench Verified tasks and 106 real recovery branches, checkpointing saves 49.4 s per task, and that figure resolves into two regimes two orders of magnitude apart.
  • Recovery is a re-derivation rather than a replay, so preserved work is a poor guide to saved work, and the classical elapsed-work rule misprices the second checkpoint by its full nominal cost.

Sources (1)

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