Nautilus Compass Memory

nautilus-compass

Open-source memory & reliability layer for AI agents.

Long-term memory that now beats mem0 on all three LongMemEval-S metrics

while staying fully local & 14× cheaper — plus drift detection and

cross-agent contracts that no other memory layer ships.

Plugin for Claude Code / Desktop · Cline · Cursor · Continue.dev · Zed ·

any MCP client.

Built by [Nautilus Platform](https://nautilus.social) · open agent ecosystem · join as agent →

🇬🇧 English (this file) · 🇨🇳 中文

October 2026 — Independent Judging & Verification (new pillar)

This project now also powers the independent judging layer of the Nautilus platform — preregistered criteria, three-state verdicts, negative results published as-is:

• NACRE judge v1 — judging knowledge compressed into a 1.7B LoRA (88.5% three-state, ECE 0.072). Model card + weights: nautilus-compass/nacre-judge-v1
• Deployment-precision discipline (preregistered, 291 cases): fp16 = 100% label agreement with bf16 anchor (safe) · int8 = 98.28% (fail) · int4 = 94.16% (forbidden). Full verdict table in-repo (docs/metering/PRECOR_BC_VERDICT_20261007.md).
• caliber-bench — a meta-benchmark that scores *benchmarks themselves* (criteria drift / contamination / judge stability). Open sample pack: nautilus-compass/caliber-bench-v0
• Harness leaderboard, Round 1 — same model, two harnesses: v5-harness 26.7% vs mini-swe-agent 16.7% (+10.0pp), every artifact sha16-addressable. Live at nautilus.social/leaderboard.html; free L1 intake at nautilus.social/intake.html.
• Casebook v1.4 (shipping 10/12) — 16 precedented judgment cases + 6 self-errata, every case independently recomputable (docs/cases/CASEBOOK_V1.md); the paid binding line's first artifact.
• Judgment-fuel corpus — 2,257 qid-deduplicated precedent cases across four sources (verdict splits / delta registry ratchet / org-fuel pipeline / outreach), live counter at nautilus.social/corpus_stats.json.
• E-NACRE-1, a published negative result — domain-routed LoRA shards regressed −36.6pp; dynamic-weight routing suspended until corpus ≥3,000. Negative results ship as first-class findings (docs/metering/PRECOR_ENACRE1_VERDICT_20261007.md).
• Full customer journey, externally verified — intake → criteria → leaderboard → status query → registry → programmatic status API (/api/judge_status), all reachable from the public internet with three-tier checks (HTTP / content anchors / live data).
• Format-regression set v1 — 26 patch-format failure cases (harness A 15 + agent B 11) from Round 1, each with defect labels and reapply expectations (runtime/outreach/rsi_regression_set_v1.jsonl), built for rsi-bench replay certification.

Memory layer (below) remains fully local & open; judging artifacts carry the same evidence discipline (measured / inferred / unverifiable — labeled).

What this is (memory layer, 2026-08 state)

Three pillars, one plugin:

1 · Black-box long-term memory — now with SOTA retrieval. Raw text embedded locally with BGE-m3. No extraction LLM at ingest, no graph, no data leaving your machine. In Aug 2026 we added utterance-routed chunk retrieval: single-session and knowledge-update questions route to turn-window chunks (the answer usually lives in ONE user turn; whole-session embedding dilutes it), everything else uses session-level hybrid (BM25 + dense RRF). Result on LongMemEval-S full 500 questions, same-question head-to-head vs mem0 2.0.19 (both sides infer=False, each on its own default embedder — bge-m3 vs vertexai text-embedding-005 — our reproduction):

One-command reproduction (retrieval-only, no LLM calls, CPU works / GPU recommended for the full 500):

bash scripts/reproduce_lmes_retrieval.sh            # full 500

SUBSET=12 bash scripts/reproduce_lmes_retrieval.sh # smoke

The same utterance ammo overtakes mem0 on its own home benchmark (LOCOMO-10, n=1986: 0.644 / 0.890 vs 0.592 / 0.802) and fixes the single-session collapse on LongMemEval-M (0.20 → 1.00). Full evidence chain with per-type breakdowns and every config flag: docs/evidence/headhead_mem0_full500_20260826.json — including the experiments that failed (cross-encoder reranking *hurts* on this corpus; candidate-pool K is a no-op; Qwen3-0.6B swap is a wash).

2 · Drift detection — the half nobody else solves. Memory recalled doesn't stop the AI from breaking the rule *this time*. compass scores every prompt against an anchor set of real failure patterns (25 positive + 35 negative) before the agent acts. AUC 0.83 held-out, p95 latency <50 ms, fire rate 0.5% in production traffic. White-box layers abstract prompts into facts before drift becomes checkable — structurally out of their reach.

3 · Cross-agent contracts + governance. When you run multiple agents (or multiple Claude dialogs) on shared files, compass derives implicit contracts from handoff files, tracks closure, and audits for fake-closure / red drift. A 4-dialog 28-hour field study lives in docs/case_study_4dialog_compass.md.

The trade that flipped: earlier versions traded −30 points on LongMemEval-S for local deployment and cost. As of 2026-08 there is no trade — full sweep at 1/14 the reproduction cost (~$3.50 per 500 questions vs $50+ for GPT-4o-judged stacks). Full argument: paper/BLACKBOX_VS_WHITEBOX.md.

Quickstart

Packages on PyPI

Python package (PyPI · 3.3.0)

pip install nautilus-compass

ships the CLI, the MCP server, the A2A adapter and session tools:

nautilus-compass · compass-mcp · compass-a2a

compass-drift-history · compass-session-search · compass-session-writer

30 seconds (Claude Code / Desktop · local daemon)

git clone https://github.com/chunxiaoxx/nautilus-compass ~/.claude/plugins/nautilus-compass

bash ~/.claude/plugins/nautilus-compass/install.sh

start the BGE-m3 daemon (one-time per boot)

bash ~/.claude/plugins/nautilus-compass/daemon_start.sh

Deploy notes (field-verified pitfalls, 2026-08-28):

- COMPASS_USE_INOTIFY=0 disables new-file discovery — recalls won't see

fresh writes, silently. Only set it if you know why; the daemon logs a

WARNING when it's off.

- drift fails loudly now: if anchors.json is missing from the plugin dir,

responses carry drift.anchors_error + should_alert: true (it used to

silently return "no risk" — that was a security hole).

- Token changes to tokens.json hot-reload via mtime check (no systemd

restart needed since v3.1.0).

- First recall after daemon idle may take up to 90 s (model cold-load); the

MCP client auto-retries once with the extended timeout.

The installer wires three hooks into ~/.claude/settings.json:

• UserPromptSubmit → time-bucketed memory recall + drift check
• PostToolUse → mid-session writer
• Stop → end-of-session summary (writes a session battle-report to ~/.claude/.cache/compass-last-session.txt)

Slash commands: /compass-verify · /compass-drift · /compass-recall · /compass-search · /compass-status.

Any other MCP client

python ~/.claude/plugins/nautilus-compass/scripts/install_to_agent.py

Auto-detects Claude Desktop, Cursor, Cline, Continue.dev, Zed and patches their MCP config. Per-agent copy-paste configs: docs/AGENT_ONBOARDING.md · raw protocol: docs/mcp-usage.md.

Cloud-hosted (open beta · self-serve)

The hosted gateway — MCP over HTTPS with scoped tokens and per-user memory isolation — is open for self-serve registration: sign up at https://compass.nautilus.social/signup, then create a token in the web console (or POST /tokens). Scopes are server-bound to your own space (read+write); cross-user access is denied and verified by automated probes. Design: docs/plans/2026-08-30-multi-tenant-memory-design.md.

MCP endpoint: https://compass.nautilus.social/mcp/ (Bearer token · streamable-http). Also listed in the official MCP Registry as io.github.chunxiaoxx/nautilus-compass (remote + PyPI self-host, dual entry) — registry-aware clients (Glama and other aggregators) can discover it from there. A2A discovery: curl https://compass.nautilus.social/.well-known/agent.json

Nautilus platform agents (cloud ssh quickstart)

For agents on machines with ssh access to your Nautilus cloud box — generates a scoped token, wires the cloud MCP bridge, writes .mcp.json, and runs an end-to-end self-check. Add --hud to install the fused status line (live recall hit-counter 🧠, drift state, 5-min traffic).

bash ~/.claude/plugins/nautilus-compass/ops/agent_quickstart.sh my-agent

Headline numbers

| LongMemEval-S 500q full (utt-routed + hybrid, n=500) | P@1 0.890 · P@5 0.978 · MRR 0.929 | sweeps mem0 2.0.19 (0.774/0.916/0.834, our reproduction, each side on its own default