Align native context management with the Claude Code / Codex model:
entry-capped tool results, history frozen below the threshold, one
high-quality summary at the wall — instead of the old pipeline that
microcompacted old messages from 60% usage and hid everything past 40
messages behind a snip marker with no summary.
- context pipeline: history below the hard threshold is never rewritten
(model quality and prompt-cache prefixes depend on byte-identical old
messages); the 60% tool-aware microcompact and the 40-message history
snip move to an emergency-only fallback used under overflow pressure
when the summarizer is unavailable or circuit-broken.
- durable compaction (was a stub): at usage >= context_guard.hard_threshold
(now 0.90, soft_threshold removed) the old span is folded into a
9-section summary via the new HistoryCompactor.summarize_runtime_history,
keeping the system head, the seed user request verbatim on every round
(injected session-memory/artifact messages shift the stale
base_prefix_len, so the fold start is structure-aware), and a
pairing-safe recent tail. A previous summary stays foldable, so exactly
one summary exists at a time and rounds chain.
- token accounting anchors on the provider-reported prompt size of the
latest request (max with the local estimate).
- reactive_compaction.circuit_breaker_failures (previously unread) now
stops repeated summarizer failures; provider overflow errors retry
through the same pipeline, summary-first.
- tool-result budget clip keeps head and tail instead of tail-chopping.
- chat-side transcripts get the same treatment: new
MemoryManager.maybe_compact_session_history wires the threshold-gated
maybe_compact_session into secretary, office_ui dispatcher, and
context_loader before prompt building, closing the unbounded-growth
path; dead no-op compactor entries (maybe_compact_after_message,
should_compact_prompt) removed.
Verified by 13 new tests (history sanctity below threshold, multi-round
single-summary/seed-verbatim/chain invariants, breaker, emergency
fallback, provider-overflow end-to-end recovery) plus a live-provider
probe: multi-round compaction with the model completing correctly from
summarized context. Full suite: 1859 passed.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
LZH-YS1998
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