A captured native-compaction checkpoint lives in the persisted
codex_reasoning_items sidecar, but the wire restructure that follows it
(prune_pre_checkpoint_items) ran unconditionally: the native gate only
decided whether context_management went into the request, and no signal
from it ever reached _chat_messages_to_responses_input.
So a single checkpoint kept deleting every pre-checkpoint item from all
later requests — after a mid-session swap out of the gpt-5.6 family,
after compression.enabled: false, after the rejection kill switch, and
after a session resume that reloads the sidecar from state.db. The model
receiving the opaque blob was no longer the one able to decode it, and
nothing was logged.
Thread a single native_compaction_eligible boolean, derived from the same
value that gates the context_management field, into the converter. When
ineligible: do not replay type: "compaction" items and do not prune. Safe
because native compaction never truncates Hermes' local history, so the
fallback still carries the full conversation.
All Responses call sites are covered: build_kwargs and convert_messages
derive the flag via _native_compaction_active, the auxiliary/compression
client is explicitly ineligible, and the converter defaults to False
(pre-feature wire) so future call sites are safe by construction.
Fixes#85914
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
joaomarcos
11c5aae104