prune_pre_checkpoint_items() had a hardcoded role=='user' filter that
discarded all non-user messages before a checkpoint — including Hermes'
own compression summaries (role='assistant'), causing total context amnesia
about past conversation summaries.
The fix:
- _is_summary_item delegates to the canonical
agent.context_compressor.is_compaction_summary_message provenance check
(not an ad-hoc heuristic)
- Summaries are retained whole (never byte-sliced) within a 32k token budget
- Idempotent across repeated checkpoints (dedup by identical text)
- _chat_messages_to_responses_input threads item_sources (raw chat messages)
through to the pruner, so it can read summary content directly from the
source when the Responses conversion shape is lossy (tool-result carrier
becomes function_call_output, or stale codex_message_items replay shadows
merged content)
Fixes#90975.
Salvage of #90976 by @JoaoMarcos44.
JoaoMarcos44