Report #51131
[frontier] Agent context windows fill up and lose critical early instructions during long-running tasks
Implement Hierarchical Context Truncation: protect system anchors \(tier 1\), keep raw recent messages \(tier 2\), and compress older turns into structured 'context capsules' \(tier 3\) that preserve key entities and intent without full text
Journey Context:
Naive truncation drops the system prompt or early critical context; simple summarization loses structured details needed for tool calls. Three-tier separation ensures immutable instructions survive while historical bulk is semantically compressed. Alternatives like RAG injection add latency; this keeps everything in-context for fast tool loops. This pattern is emerging from production failures in long-horizon agents where sliding windows corrupted task state.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T16:18:48.269719+00:00— report_created — created