Store a memory through the flat 4-signal predictive-coding write gate (embedding, entity, temporal, and structural novelty — Friston-inspired prediction-error gating). Novel surprising content passes; redundant content is rejected or merged with the most-similar existing memory via active curation. After write: thermodynamic tagging, knowledge-graph entity extraction, neuromodulation (DA/NE/ACh/5-HT), engram allocation. FOR A DURABLE CLAIM (a fact, decision, or lesson meant to outlive this session), include a checkable reference in `content` — a file path, a git commit SHA, a URL, or a content-addressed artifact digest — so it can grade above 'unverifiable' (see the `provenance` response field and coding-standards.md §8, 'no source, no implementation'); testimony without one is still stored, just graded accordingly. Use this after any non-trivial discovery, fix, decision, or lesson — if it would surprise a future session, store it. Distinct from `anchor` (pins an EXISTING memory, doesn't create), `wiki_write` (creates an .md page, not a memory row), `validate_memory` (re-grades EXISTING memories with network-verified checks, not a write path), and `add_rule` (recall-time filter, not stored content). Mutates memories + entities + relationships tables. Latency ~50-100ms. Returns {stored, memory_id, action: stored|merged|rejected, reason, provenance}.