The load-bearing L10 milestone: with resume mode enabled, a reboot resumes the
SAME life. Wires SessionContext.snapshot/restore (Phases A-C) into the
engine-state checkpoint and flips the L10 spike's P2b oracle to transparent.
Persistence is OPT-IN (RuntimeConfig.persist_session_state, default False): it is
a deliberate always-on-runtime mode, and per-turn snapshotting has an O(turns)
cost, so demos / evals / one-shot runtimes do NOT pay for resume they don't use.
This keeps every existing ChatRuntime byte-for-byte unchanged (no perf tax, no
pinned-lane SHA drift, no test breakage); only the L10 continuity lane and the
production L10 process enable it.
Phase D (wiring):
- core/config.py: persist_session_state flag (default False).
- engine_state/__init__.py: bump _SCHEMA_VERSION 1->2; add save_session_state /
load_session_state (atomic, ADR-0156). v1 checkpoints still load (1 <= 2) with
no session_state -> fresh session.
- chat/runtime.py: when persist_session_state, checkpoint_engine_state saves the
session snapshot BEFORE the manifest (manifest = the commit marker / WAL force
boundary); _load_engine_state restores it into self._context.
Phase E (flip the oracle):
- evals/l10_continuity/runner.py: the continuity lane forces persist on (it IS
the resume-mode lane).
- tests/test_l10_continuity.py: test_p2b_documents_current_resume_gap ->
test_p2b_reboot_is_transparent (asserts post_reboot_transparent, divergence
None). predicates.py / runner.py / contract.md: P2b is now the
resume-as-same-life guard.
- tests/test_adr_0146_engine_state.py: manifest schema_version 1 -> 2.
Validation: full spike (P1 closure, P2a determinism, P2b NOW TRANSPARENT, P3
bounded, P4 crash-recovery determinism + commit point, P5b/P5c) +
reboot-restores-lived-state + v1 back-compat + ADR-0146, all green;
[run K -> reboot -> run M] byte-identical to [run K+M]. With persistence off
(default), the curated smoke + showcase budget + pinned lanes are unchanged.
Closes the A->E Shape B+ scope (docs/analysis/L10-shapeBplus-persistence-scope-2026-06-05.md).
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