fix(memory): order get_last_k_turns messages chronologically#552
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fix(memory): order get_last_k_turns messages chronologically#552valter-silva-au wants to merge 1 commit into
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The ListEvents API returns events newest-first, but get_last_k_turns grouped them in arrival order. Because a new turn is started at each USER message, processing newest-first misaligns turns — an ASSISTANT reply is orphaned into a leading turn and every subsequent turn pairs a USER message with the previous turn's ASSISTANT response. The effect is most visible when tool use splits a turn across single-message events. Sort each fetched batch by eventTimestamp (oldest-first) before grouping, in both MemoryClient.get_last_k_turns and MemorySessionManager.get_last_k_turns. The sort is skipped when any event in the batch lacks a timestamp, preserving existing behavior for callers that don't supply one. Public signatures and pagination are unchanged. Add regression tests in both modules that feed events newest-first (as the real API does) and assert a single, correctly ordered USER->ASSISTANT turn. Fixes aws#253
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Summary
get_last_k_turnsgroups events into turns by starting a new turn at eachUSERmessage. The ListEvents API returns events newest-first, but the method iterated them in arrival order without re-sorting. As a result, anASSISTANTreply is orphaned into a leading turn and every subsequent turn pairs aUSERmessage with the previous turn'sASSISTANTresponse — the whole conversation is shifted by one. The effect is most visible when tool use splits a turn across single-message events (as in the issue report).This sorts each fetched batch by
eventTimestamp(oldest-first) before grouping, in bothMemoryClient.get_last_k_turnsandMemorySessionManager.get_last_k_turns. The sort is skipped when any event in the batch lacks a timestamp, preserving existing behavior for callers that don't supply one. Public signatures and pagination behavior are unchanged.Fixes #253
Changes
src/bedrock_agentcore/memory/client.pyandsrc/bedrock_agentcore/memory/session.py: sort each batch chronologically before turn grouping.tests/.../test_client.pyandtests/.../test_session.py: add regression tests that feed events newest-first (as the real API does) and assert a single, correctly orderedUSER→ASSISTANTturn.Note for maintainers
This fixes the reported message-alignment bug with a minimal, per-batch sort. There is a separate, latent question of whether
turns[:k]should return the first or the lastkturns once ordering is chronological — I've intentionally left that out of scope to keep this change small and behavior-preserving. Happy to follow up separately if you'd like that addressed too.Testing
uv run pytest tests/bedrock_agentcore/memory/(excluding the credential-gated strands integration tests) — all pass.