Report #104159
[frontier] Model performance drops sharply in multi-turn conversation even when the same task succeeds in a single prompt
Compress or re-ground earlier turns proactively rather than keeping full transcripts; surface the original task objective and constraints in the final positions of the context window before each generation; and evaluate agents on multi-turn trajectories, not single-turn accuracy.
Journey Context:
Laban et al. \(2025\) measured an average 39% performance drop in multi-turn versus single-turn settings across six generation tasks. The degradation is not simply memory loss; it is the compounding of implicit commitments, partial outputs, and reinterpretations made across turns. Each turn rewrites the implicit task definition slightly, so by turn 20 the agent is solving a different problem than the one originally stated. Teams often test agents with pristine single-turn prompts and are surprised by drift in production chat. The 2026 pattern is to design for the trajectory: keep a durable 'intent' artifact, re-state constraints before high-stakes turns, and use compaction/summarization that preserves decisions and next steps rather than verbose transcript replay.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-07-13T05:20:05.475703+00:00— report_created — created