YantrikDB — A Cognitive Memory Engine for Persistent AI Systems

The memory engine for AI that actually knows you.

Get Started in 60 Seconds

For AI agents (MCP — works with Claude, Cursor, Windsurf, Copilot)

pip install yantrikdb-mcp

Add to your MCP client config:

{
  "mcpServers": {
    "yantrikdb": {
      "command": "yantrikdb-mcp"
    }
  }
}

That's it. The agent auto-recalls context, auto-remembers decisions, and auto-detects contradictions — no prompting needed. See yantrikdb-mcp for full docs.

As a Python library

pip install yantrikdb

import yantrikdb
from sentence_transformers import SentenceTransformer

# Single file, no server, no config
db = yantrikdb.YantrikDB("memory.db", embedding_dim=384)
db.set_embedder(SentenceTransformer("all-MiniLM-L6-v2"))

# Record memories with importance, domain, and emotional valence
db.record("Alice is the engineering lead", importance=0.8, domain="people")
db.record("Project deadline is March 30", importance=0.9, domain="work")
db.record("User prefers dark mode", importance=0.6, domain="preference")

# Semantic recall — ranked by relevance, recency, importance, and graph proximity
results = db.recall("who leads the team?", top_k=3)
# → [{"text": "Alice is the engineering lead", "score": 1.0}, ...]

# Knowledge graph — entity relationships
db.relate("Alice", "Engineering", "leads")
db.get_edges("Alice")
# → [{"src": "Alice", "dst": "Engineering", "rel_type": "leads", "weight": 1.0}]

# Cognitive maintenance — consolidate, detect conflicts, mine patterns
db.think()
# → {"consolidation_count": 2, "conflicts_found": 0, "patterns_new": 1}

db.close()

As a Rust crate

[dependencies]
yantrikdb = "0.4"

The Problem

Current AI memory is:

Store everything → Embed → Retrieve top-k → Inject into context → Hope it helps.

That's not memory. That's a search engine with extra steps.

Real memory is hierarchical, compressed, contextual, self-updating, emotionally weighted, time-aware, and predictive. YantrikDB is built for that.

Why Not Existing Solutions?

Benchmark: Selective Recall vs. File-Based Memory

At 500 memories, file-based exceeds 32K context windows. At 5,000, it doesn't fit in any context window — not even 200K. YantrikDB stays at ~70 tokens per query. Precision improves with more data — the opposite of context stuffing.

Architecture

Design Principles

• Embedded, not client-server — single file, no server process (like SQLite)
• Local-first, sync-native — works offline, syncs when connected
• Cognitive operations, not SQL — record(), recall(), relate(), not SELECT
• Living system, not passive store — does work between conversations
• Thread-safe — Send + Sync with internal Mutex/RwLock, safe for concurrent access

Five Indexes, One Engine

┌──────────────────────────────────────────────────────┐
│                   YantrikDB Engine                    │
│                                                      │
│  ┌──────────┬──────────┬──────────┬──────────┐       │
│  │  Vector  │  Graph   │ Temporal │  Decay   │       │
│  │  (HNSW)  │(Entities)│ (Events) │  (Heap)  │       │
│  └──────────┴──────────┴──────────┴──────────┘       │
│  ┌──────────┐                                        │
│  │ Key-Value│  WAL + Replication Log (CRDT)          │
│  └──────────┘                                        │
└──────────────────────────────────────────────────────┘

1. Vector Index (HNSW) — semantic similarity search across memories
2. Graph Index — entity relationships, profile aggregation, bridge detection
3. Temporal Index — time-aware queries ("what happened Tuesday", "upcoming deadlines")
4. Decay Heap — importance scores that degrade over time, like human memory
5. Key-Value Store — fast facts, session state, scoring weights

Memory Types (Tulving's Taxonomy)

All memories carry importance, valence (emotional tone), domain, source, certainty, and timestamps — used in a multi-signal scoring function that goes far beyond cosine similarity.

Key Capabilities

Relevance-Conditioned Scoring

Not just vector similarity. Every recall combines:

• Semantic similarity (HNSW) — what's topically related
• Temporal decay — recent memories score higher
• Importance weighting — critical decisions beat trivia
• Graph proximity — entity relationships boost connected memories
• Retrieval feedback — learns from past recall quality

Weights are tuned automatically from usage patterns.

Conflict Detection & Resolution

When memories contradict, YantrikDB doesn't guess — it creates a conflict segment:

"works at Google" (recorded Jan 15) vs. "works at Meta" (recorded Mar 1)
→ Conflict: identity_fact, priority: high, strategy: ask_user

Resolution is conversational: the AI asks naturally, not programmatically.

Semantic Consolidation

After many conversations, memories pile up. think() runs:

1. Consolidation — merge similar memories, extract patterns
2. Conflict scan — find contradictions across the knowledge base
3. Pattern mining — cross-domain discovery ("work stress correlates with health entries")
4. Trigger evaluation — proactive insights worth surfacing

Proactive Triggers

The engine generates triggers when it detects something worth reaching out about:

• Memory conflicts needing resolution
• Approaching deadlines (temporal awareness)
• Patterns detected across domains
• High-importance memories about to decay
• Goal tracking ("how's the marathon training?")

Every trigger is grounded in real memory data — not engagement farming.

Multi-Device Sync (CRDT)

Local-first with append-only replication log:

• CRDT merging — graph edges, memories, and metadata merge without conflicts
• Vector indexes rebuild locally — raw memories sync, each device rebuilds HNSW
• Forget propagation — tombstones ensure forgotten memories stay forgotten
• Conflict detection — contradictions across devices are flagged for resolution

Sessions & Temporal Awareness

sid = db.session_start("default", "claude-code")
db.record("decided to use PostgreSQL")  # auto-linked to session
db.record("Alice suggested Redis for caching")
db.session_end(sid)
# → computes: memory_count, avg_valence, topics, duration

db.stale(days=14)    # high-importance memories not accessed recently
db.upcoming(days=7)  # memories with approaching deadlines

Full API

Technical Decisions

Ecosystem

Roadmap

• V0 — Embedded engine, core memory model (record, recall, relate, consolidate, decay)
• V1 — Replication log, CRDT-based sync between devices
• V2 — Conflict resolution with human-in-the-loop
• V3 — Proactive cognition loop, pattern detection, trigger system
• V4 — Sessions, temporal awareness, cross-domain pattern mining, entity profiles
• V5 — Multi-agent shared memory, federated learning across users

Worked example: Wirecard (RFC 008 substrate — with honest limits)

For nearly a decade, Wirecard's filings and EY's audit attested to €1.9B in Philippine escrow accounts. In June 2020 both banks and the central bank formally denied the accounts existed.

When the source_lineage fields are hand-populated — EY as [wirecard, ey] to capture audit dependence on Wirecard-provided documents, BSP as [bsp, bpi, bdo] to capture restatement of the commercial banks — RFC 008's ⊕ discounts the dependent claims, and the contest operator's temporal split distinguishes present-tense contradictions from historical state changes. On this hand-populated data, the substrate produces useful annotations.

Honest limits (surfaced by Phase 2 empirical testing, Apr 2026):

• On naturalistic evidence where a real agent populates the fields, the substrate's gates don't reliably fire. Cases B and C of the Phase 2 eval need an extractor/canonicalizer (not yet built) to work; Case A exposed that ⊕ is mathematically incapable of flipping decisions at realistic N, regardless of coefficient tuning.
• Current claim: structured schema for evidence provenance/temporal/conflict annotation, useful for audit and inspection. The dependence-discount operator works on curated inputs but needs replacement before it can drive decisions.
• Not a current claim: "decision-improvement substrate for AGI-capable agents." That framing is withdrawn pending RFC 009.

See docs/showcase/wirecard.md for the full walkthrough including the Phase 2 negative result and the gold-state ablation that partitioned operator failure from extraction failure. Run the hand-populated demonstration directly:

cargo run --example showcase_wirecard

Research & Publications

• U.S. Patent Application 19/573,392 (March 2026): "Cognitive Memory Database System with Relevance-Conditioned Scoring and Autonomous Knowledge Management"
• Zenodo: YantrikDB: A Cognitive Memory Engine for Persistent AI Systems

Author

Pranab Sarkar — ORCID · LinkedIn · developer@pranab.co.in

License

AGPL-3.0. See LICENSE for the full text.

The MCP server is MIT-licensed — using the engine via the MCP server does not trigger AGPL obligations on your code.