Milestone 2.5.G5.M1 — Temporal Validity Columns

Status: Completed (2026-08-24)
Goal: Track E — Schema Pre-Work
Phase: 2.5 — Provider Generalization & Foundation
Estimated effort: 0.5 days
ADR: ADR-0047

Why This Milestone Exists

The schema tracked memory lifecycle status (active/superseded/merged_into/archived/quarantined/deleted) but had no notion of when a fact was true, which is exactly the gap Zep/Graphiti-style temporal graphs close.

This is the schema-level fix for the "contradiction requires a similarity threshold to even detect" problem — a contradiction becomes two rows with overlapping [valid_from, valid_until) ranges and a contradicts edge in memory_relationships, rather than requiring the extraction worker to silently pick a winner.

This milestone is migration-only, additive, and unused by application code yet — the point is to have the right shape in Postgres before Phase 3's write pipeline is built against it.

Non-Goals

Application code reading or writing the new columns (Phase 3)
Temporal query patterns or indexes (Phase 3)
Backfilling historical valid_from values (no prior rows)
Embedding / pgvector / HNSW (Phase 3.1.1 expand)
memory_categories / memory_relationships (G5.M2 / G5.M3)

What shipped

Migration 000014_create_memories_temporal — CREATE ibex_core.memories (not ALTER)
Columns: valid_from / valid_until / observed_at plus lean content, category, status, tenancy
CHECK (valid_until IS NULL OR valid_until > valid_from); half-open interval documented in ADR-0047
FORCE ROW LEVEL SECURITY + ibex_core.rls_org_visible; composite (agent_id, org_id) FK; UNIQUE (id, org_id)
Optional session_id composite FK; clear via trigger on session delete
Integration tests: columns/defaults/CHECK/RLS/idempotent up
Docs: ADR-0047, DATABASE_SCHEMA.md, 3.1.1 expand-not-CREATE callout

Success signals

Migration creates ibex_core.memories with valid_from, valid_until, observed_at
valid_from and observed_at have DEFAULT NOW() and are NOT NULL
valid_until is nullable
Migration is forward-only in production (down is dev/test only per ADR-0005)
Migration applies cleanly: make db-migrate / integration Up exits 0
No application code reads or writes the new columns in this milestone
Consistent with expand-contract (3.1.1 expands; does not double-CREATE)

Prerequisites

Track D (embedder) merged — sequencing only; no code dependency
Sessions / agents / RLS helpers from Phase 2 migrations (000007–000010)

Orientation (historical sketch)

The original sketch used ALTER TABLE. That path was invalid because the table did not exist. Kept for orientation only:

SQL

-- Sketch only — do not apply; shipped path is CREATE in 000014
ALTER TABLE ibex_core.memories
 ADD COLUMN valid_from TIMESTAMPTZ NOT NULL DEFAULT NOW(),
 ADD COLUMN valid_until TIMESTAMPTZ,
 ADD COLUMN observed_at TIMESTAMPTZ NOT NULL DEFAULT NOW();

Column semantics

Column	Meaning	Nullable
`valid_from`	When the fact described by this memory became true in the real world	No (defaults to `NOW()` on insert)
`valid_until`	When the fact ceased to be true (`NULL` = still valid)	Yes
`observed_at`	When IBEX learned this fact (distinct from when it became true)	No (defaults to `NOW()` on insert)

Why observed_at is distinct from valid_from: A user might tell IBEX "I moved to Berlin three years ago" — the fact (valid_from = 3 years ago) and the observation (observed_at = now) are different instants.