Root cause: when consolidation LLM fails, raw_archive() dumped full message
content (~1MB) into history.jsonl with no size limit. Since build_system_prompt()
injects history.jsonl into every system prompt, all subsequent LLM calls exceeded
the 200K context window with error 1261.
Additionally, _cap_consolidation_boundary's 60-message cap caused consolidation
to get stuck on sessions with long tool chains (200+ iterations), triggering
the raw_archive fallback in the first place.
Three-layer fix:
- Remove _cap_consolidation_boundary: let pick_consolidation_boundary drive
chunk sizing based solely on token budget
- Truncate archive() input: use tiktoken to cap formatted text to the model's
input token budget before sending to consolidation LLM
- Truncate raw_archive() output: cap history.jsonl entries at 16K chars
chengyongruandXubin Ren
2848f69897