Description

_create_memory (both sync Memory and async AsyncMemory) had three gaps in how it handled timestamps:

Problem 1: updated_at was never set on creation

When a memory was first created, only created_at was set. updated_at remained None in the vector store payload until the memory was explicitly updated via _update_memory. This caused:

• Inconsistent API responses — consumers had to null-check updated_at since it was sometimes a string, sometimes None
• Broken sorting/filtering — sorting by updated_at (e.g. "most recently changed") dropped all never-updated memories
• Wrong "last modified" queries — queries like "memories changed since X" missed memories created after X but never updated

Problem 2: created_at was unconditionally overwritten

metadata["created_at"] = datetime.now(timezone.utc).isoformat()

If any caller pre-set created_at in the metadata dict (e.g. an integration backdating a memory, or the platform API honoring a user-provided timestamp), it was silently overwritten with the current time.

Problem 3: History table missing updated_at for ADD events

_update_memory passed updated_at to db.add_history(), but _create_memory did not — leaving the updated_at column NULL for all ADD history entries, even though the value was available.

Solution

In both sync and async _create_memory:

1. Guard created_at with if "created_at" not in metadata — only auto-generate if not already present
2. Set updated_at = created_at — a newly created record was "last modified" at creation time
3. Pass updated_at to db.add_history() — consistent with _update_memory behavior

Related to #3720

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

19 tests in tests/memory/test_main.py (7 new + 12 existing), all passing.

New tests:

Existing tests (all still pass):

• test_create_memory_uses_utc_timestamps — created_at is UTC
• test_update_memory_uses_utc_timestamps — updated_at is UTC, created_at preserved and normalized
• Async equivalents of both
• 4 _normalize_iso_timestamp_to_utc tests
• 4 _add_to_vector_store error handling tests

Also verified against the broader test suite:

tests/memory/test_main.py  — 19 passed
tests/test_memory.py       — 21 passed
tests/test_server_auth.py  — 74 passed
                             ─────────
                             114 passed, 0 failed

• Unit Test

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have checked my code and corrected any misspellings

Maintainer Checklist

• Related to The value of created_at differs between search and get_all results #3720
• Made sure Checks passed