Chronicle: Cut-Point Replay for Regression Testing of LLM Agents

TL;DR - Chronicle turns recorded LLM-agent failures into reproducible regression tests using cut-point replay, selectively replaying nondeterministic boundaries while executing changed code live. This enables stable, low-overhead incident testing in continuous integration.

• Records model and tool boundary interactions as immutable envelopes for deterministic replay.
• Full replay made zero model calls and remained bit-stable across 20 repetitions.
• Across six recorded incidents, cut-point tests rejected faulty code while accepting guarded and benign changes.
• Cut-point testing caught every mutation that allowed a recorded unsafe action; fully stubbed baseline tests caught none.