Recovery Under Drift: When Failed Context Helps or Hurts

Failed context can contain both misleading content and correct task information, so removing it changes two things at once. We study this trade-off with controlled interventions that vary correct facts inside a partly wrong record, correct facts supplied separately, failed-code visibility, the source of failures used for training, and conversation retention at fixed files. In tool-use and ALFWorld recovery states, adding correct facts to the retained record raises its benefit for Qwen3-8B and Gemma-4-12B-it. A complete current reference lowers retention benefit in the tool setting, whereas the ALFWorld intervals do not establish the same change. A secondary Qwen tool comparison finds that partial external facts can first increase the record's benefit before a complete reference lowers it. Code experiments show that measured recovery also depends on restart context and failure source: for one 7B model, omitting failed code and feedback raises success within 64 attempts from 22.1% to 55.5%, and matched-source training gains exceed mismatched gains across five model settings. On 34 MettleBench failures at identical repository files, retaining the pre-checkpoint conversation raises mean recovery from 11.8% to 35.8%. Recovery evaluations should state what each condition retains, compare repair with fresh starts, and match inference budgets.