An agent that runs long enough outgrows its context window, so the platform compresses what came before into a carried-forward summary. OpenAI's documentation says that summary is not meant to be read by a person, which means when a long task goes wrong there is no way to see what was dropped.
What people are trying
- Compaction · OpenAI · read 09/19/2026
It is opaque and not intended to be human-interpretable.
Where it bites: Long-running tasks