Status: Proposed · Authored 2026-07-14 · Builds on
docs/V2_PLAN.md("Git for your AI's memory") and the shipped v2 engine. Research backing: a July-2026 frontier sweep (agent-memory survey + arXiv preprints, coding long-horizon benchmarks, context-engineering/compaction, on-device embeddings). Source appendix at the end. This doc is the contract for what v3 is and the order we build it.
v1 made memory local and ownable. v2 made it portable, signed, and mergeable — "Git for your AI's memory." The field has since moved again, and v3 answers where it went.
The 2026 research consensus is sharp and consistent across independent groups:
- Memory is becoming active, not a passive store. The frontier is Memory-as-Action —
the agent decides when to write, edit, compact, and forget as first-class actions, and
context compaction (Anthropic's
compact-2026-01-12API; CompactionRL; Self-Compacting agents) is now the dominant way long-horizon agents survive. The open question is where the dropped context goes. Today it evaporates. That's Helix's opening: be the durable sink for compaction. - Experience must compound, with fair credit assignment. Memory-R2, Fine-Mem, and DELTAMEM all attack the same problem: an agent should get measurably better from its own outcomes, and each memory should be rewarded/penalized in proportion to how much it actually helped. v2 shipped this for procedures (reliability grows on confirmed reuse). v3 generalizes it to every fact — the strand demonstrably improves, and we can prove it.
- Temporal reasoning is the #1 unsolved gap. Independent benchmarks (LongMemEval-V2, LoCoMo temporal split) show up to 15-point accuracy gaps on "when/why did this change?" queries — the single weakest axis across every memory architecture. Helix already stores bi-temporal columns almost nobody else has. v3 turns that latent asset into a temporal reasoning surface that answers belief-change queries directly.
- Coding memory needs its own eval, and long-horizon software evolution is the arena. SWE-EVO and the "knowledge compounding / agentic ROI" line argue the metric that matters is not chat recall — it's does the agent's stored experience make the next task cheaper and more likely to succeed? v3 ships that benchmark.
The v3 thesis in one line: v1 you own it, v2 you move it — v3 it compounds. Helix is the only local-first, portable memory that makes your coding agent measurably better over time, proves it with a coding-native benchmark, and is the durable place your agent's context goes when it compacts.
Like v2, v3 is additive, not a rewrite. The engine, .dna container, and MCP surface all
stand; v3 adds an experience/credit-assignment layer, a temporal-reasoning surface, a
compaction bridge, and the eval that scores them — every piece $0/offline by default.
PASSIVE STORE ─────────────────────────────► ACTIVE / AGENTIC MEMORY
(RAG-over-facts) (Memory-as-Action, self-editing)
v1 ● ────────► v2 ● (portable/mergeable) ────────► ★ v3 (compounding + active)
Axes the 2026 papers converged on, and where Helix stands:
┌────────────────────────────┬───────────────────────────────┬──────────────┐
│ Frontier axis │ SOTA direction (2026) │ Helix today │
├────────────────────────────┼───────────────────────────────┼──────────────┤
│ Active / self-managing │ Memory-as-Action, compaction │ passive → v3 │
│ Experience compounding │ Memory-R2 credit assignment │ procedures→v3│
│ Temporal reasoning │ bi-temporal + change events │ columns → v3 │
│ Long-horizon coding eval │ SWE-EVO, agentic ROI │ recall eval │
│ On-device embeddings │ EmbeddingGemma / Qwen3 / jina │ bge-small │
└────────────────────────────┴───────────────────────────────┴──────────────┘
Helix keeps the two structural advantages no funded competitor can copy without abandoning their cloud-first economics — local-first ownership and a portable signed strand — and now claims a third the incumbents aren't even chasing yet: memory that compounds and proves it, offline.
Each capability carries an effort tag (S/M/L) and a priority (P0 = v3.0 headline, P1 = v3.x, P2 = later). Everything runs at $0 with no network unless a row says otherwise; cloud stays opt-in.
The defining v3 capability. v2 proved the mechanism on procedures; v3 makes the whole strand learn from outcomes and dramatizes the result.
Helix's bi-temporal columns are a latent asset; v3 exposes them as answers.
| # | Capability | What it adds | Effort | Pri |
|---|---|---|---|---|
| 2.1 | history_of(subject) — belief timeline |
The ordered history of what Helix believed about a subject: current + superseded facts by valid_from, with each transition (from→to→when). Directly answers the temporal queries where every architecture loses 15 points. Builds on v2's changes/as_of. |
M | P0 |
| 2.2 | Temporal query grammar | Parse "as of", "when did", "before/after" phrasing in recall and route to the bitemporal path instead of pure semantic match — so an agent's natural question hits the right index. | M | P1 |
| 2.3 | Change-point summaries | On demand, summarize the arc of a decision ("Postgres→Mongo→Postgres, and why each time") from the supersession chain. LLM-optional; deterministic fallback lists the transitions. | S | P1 |
The single biggest new integration surface in 2026. When an agent compacts, the pruned context is exactly the distilled-facts Helix exists to keep.
| # | Capability | What it adds | Effort | Pri |
|---|---|---|---|---|
| 3.1 | distill_session(messages) — pre-compaction sink |
A named surface that takes an agent's about-to-be-dropped working context and distills durable facts from it (reuses batched extraction + the redaction/gate pipeline). The compaction handoff the ecosystem is standardizing around, made durable and local. | M | P0 |
| 3.2 | memory_distill / memory_outcome MCP tools |
Expose the compaction sink and the credit-assignment loop to agents over MCP — the two operations that make memory active from the agent's side (ADR-038, grows the surface 10→12, still small). | S | P0 |
| 3.3 | Compaction-aware provenance | Facts distilled at compaction carry a compaction origin marker so the dashboard can show "learned while compacting session X" and the user can audit the automatic sink. |
S | P1 |
| 3.4 | Reflection-on-session | After a session, synthesize the 1–3 durable lessons (not every turn) — sleep-time consolidation triggered by the session boundary rather than a cron. | M | P1 |
v2 promised a coding eval; v3 makes it the yardstick and scores the new capabilities.
| # | Capability | What it adds | Effort | Pri |
|---|---|---|---|---|
| 4.1 | Compounding & temporal eval metrics | Extend helix eval with: reuse-rate, build-green-after-recall proxy, stale-catch rate, temporal-accuracy (does history_of answer the change query?), and an agentic-ROI proxy (did recall make the second attempt cheaper?). |
M | P0 |
| 4.2 | SWE-EVO-style scenario harness | A small, local, multi-episode scenario (a project evolving over "sessions") that exercises compounding end-to-end — the honest coding analog to LongMemEval-V2's trajectory benchmark. | L | P1 |
| 4.3 | Regression gate in CI | Fail the build if compounding/temporal metrics drop below a floor — the eval becomes a contract, not a report. | S | P1 |
Non-headline but overdue; each is gated and $0-preserving.
The thesis made real, entirely $0/offline/deterministic:
- Compounding: 1.1 credit assignment for every fact, 1.2 experience-weighted ranking, 1.3 the compounding meter.
- Temporal: 2.1
history_of(subject). - Compaction bridge: 3.1
distill_session, 3.2memory_outcome+memory_distillMCP tools. - Prove it: 4.1 compounding + temporal eval metrics.
- Full SDK parity + docs (ADR-038) + tests.
- 1.4 auto-skill distillation, 1.5 low-reliability review, 2.2 temporal grammar, 2.3 change summaries, 3.3 compaction provenance, 3.4 reflection-on-session, 4.2 SWE-EVO harness, 4.3 CI regression gate.
- 5.1 embedding refresh, 5.2 local-LLM extraction, 5.3 perf budgets. Dashboard surfaces for the compounding meter + belief timeline.
- Compounding is real: after recording outcomes, proven facts rank measurably higher and the compounding meter climbs across a scenario — verified in the eval, not asserted.
- Temporal accuracy:
history_ofanswers belief-change queries the pure-semantic path misses (closes the documented 15-point gap on the local eval). - Compaction sink works: a dropped working-context distills to durable, sourced, redacted facts — round-tripped in a test.
- $0 promise intact: every Wave-A capability makes zero network calls; the compounding meter, like the $0 meter, is computed locally.
- No core path may require a network call or cloud account. Credit assignment is offline arithmetic, not RL; RL/auto-tuning stays opt-in cloud (v2 §1.7).
- Never store raw transcripts —
distill_sessiondistills, it does not log. The compaction sink keeps facts, not the dropped tokens. - Credit assignment never auto-deletes; low reliability routes to the review queue. The user owns the memory.
- Every new fact still carries
source · created_at · confidence · type; experience addsreliabilitywithout dropping any of them. - Don't bloat the MCP surface: v3 adds exactly two agent-facing tools, both central to active memory, documented and ADR'd.
- Credit-assignment noise — a single outcome shouldn't swing ranking. Mitigate with Laplace smoothing + a bounded, neutral-at-baseline multiplier (Wave A ships conservative constants).
- Temporal surface complexity — keep
history_ofdeterministic over existing columns; defer the NL grammar (2.2) to Wave B. - Compaction-sink over-capture — the gate + redaction still apply; distill, never log; mark provenance so the user can audit.
- Eval over-fitting — the coding eval is a floor and a compass, not a leaderboard to game; keep it honest and local.
Agent-memory frontier: Memory in the Age of AI Agents: A Survey (Agent-Memory-Paper-List), Fine-Mem (arXiv 2601.08435), SAM: State-Adaptive Memory (2605.24468), Memory-R2 (2605.21768), DELTAMEM (2606.03083), ACE: Adaptive Context Elasticizer (2606.31564), Agentic Memory: Unified Long/Short-Term Management, EverMemOS, Memory as Action: Autonomous Context Curation, The State of AI Agent Memory in 2026 (vektor/mem0), 2026 Memory Literature Scan.
Coding / long-horizon eval: SWE-EVO (2512.18470), LongMemEval-V2 (2605.12493), LoCoMo + temporal split, BEAM, LOCA-bench (2602.07962), Knowledge Compounding / Agentic ROI (2604.11243), Hippocampus memory module (2602.13594), ByteRover 2.0 LoCoMo results.
Context engineering / compaction: Anthropic Effective context engineering for AI agents +
the compaction API (compact-2026-01-12), CompactionRL (2607.05378), Self-Compacting LM Agents
(2606.23525), Slipstream trajectory-grounded compaction (2605.08580), subagent context isolation.
On-device embeddings: EmbeddingGemma (arXiv 2509.20354), Qwen3-Embedding (2506.05176), jina-embeddings-v3, BGE-M3 + BGE-reranker-v2, bge-code-v1, nomic-embed-text-v2; Matryoshka + int8 quantization; local-on-Apple-Silicon comparisons (June 2026).
