Fix conversation memory replaying history newest-first instead of oldest-first - #54
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…est-first AgentCoreMemoryProvider loaded chat history in the order returned by the AgentCore Memory ListEvents API, which is newest-first. Because the events were appended without sorting (and TryConvertEventToChatMessage dropped the EventTimestamp), history was presented to the model in reverse chronological order. Multi-turn follow-ups such as "prices please" then bound to the oldest turn instead of the most recent one. LoadHistoryAsync now sorts events ascending by EventTimestamp before converting them, so history is presented oldest-first. OrderBy is a stable sort, preserving relative order for events sharing a timestamp. The in-memory Memory emulator (AWS.AgentCore.Testing) previously returned events oldest-first, which did not match the real service and masked this bug. It now returns events newest-first to match production, and its tests were updated accordingly. A regression test feeds events newest-first and asserts the provider returns them oldest-first.
normj
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Aug 20, 2026
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Minor nit for the change log but otherwise change looks good.
dscpinheiro
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Aug 20, 2026
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Problem
AWS.AgentCore.Hosting's conversation-memory provider replays chat history newest-first instead of oldest-first, so multi-turn follow-ups bind to a stale turn.Repro:
Because history comes back reversed, the oldest turn (dinners) ends up sitting right before the new "prices please" prompt, so that's what the model latches onto. OTel
gen_ai.input.messagesspans confirm the reversed order; the equivalent Strands/Python agent orders correctly.Root cause
AgentCoreMemoryProvider.LoadHistoryAsyncappendedListEventsresults without sorting. The AgentCore MemoryListEventsAPI returns events newest-first, and there was noOrderBy(EventTimestamp).TryConvertEventToChatMessagedroppedevt.EventTimestamp, so nothing downstream could re-sort.AWS.AgentCore.Testingreturned events oldest-first, the opposite of the real service.Fix
AgentCoreMemoryProvider.LoadHistoryAsyncnow collects events and sorts them ascending byEventTimestamp(stable sort) before converting, so history is presented oldest-first. Partial-pagination and error semantics are unchanged.InMemoryEventStore.ListEvents(emulator) now returns events newest-first to match the real service, so local test harnesses exercise the same ordering as production. Its unit + property tests were updated accordingly.Testing
AWS.AgentCore.Hosting.UnitTests: 102 passedAWS.AgentCore.Testing.UnitTests: 42 passedChange files
Minor version bump for both
AWS.AgentCore.HostingandAWS.AgentCore.Testing.