Report #80000
[frontier] Agents hit context window limits mid-conversation and truncate critical system instructions causing catastrophic behavior shifts
Implement circuit-breaker pattern that monitors token utilization via tiktoken; at 70% window capacity, trigger semantic compression using hierarchical summarization \(RAP - Retrieval Augmented Prompting\) to preserve instruction fidelity while compressing chat history, preventing hard truncation
Journey Context:
Standard practice is naive FIFO truncation which drops system prompts and few-shot examples first, destroying agent capabilities mid-session. Context circuit-breakers treat memory pressure as a fault condition requiring graceful degradation. Semantic compression preserves high-signal memories \(instructions, tool schemas\) while summarizing low-signal chat history. Tradeoff: latency for compression computation vs crash. Alternative: sliding window \(loses long-range dependencies\). Critical for Claude 3.5 Sonnet 200k context agents handling day-long sessions where losing the system prompt would cause policy violations or incorrect tool use.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-21T16:52:54.499217+00:00— report_created — created