smrti

AtomSpace-inspired memory engine for AI agents. Stores beliefs as graph nodes with Bayesian truth values, emotional valence, and attention weights in a single SQLite file with vector indexing. No extra infra to maintain. Just Plug & Play.

How It Works

When an agent calls remember(), Smrti embeds the text, resolves any entities it mentions (via a 4-tier cascade: exact → alias → fuzzy → embedding), and stores the result as a typed graph node (concept, belief, episode, or goal) carrying a Bayesian truth value, an attention weight, and an emotional valence score. Every observation is appended to an immutable evidence log — truth values are never mutated directly.

On recall(), the query is embedded and matched against the tenant-partitioned vector index (sqlite-vec KNN). Results are expanded one hop through the graph, then ranked by a salience formula that blends semantic similarity, short/long-term attention, confidence, and emotional intensity. When a memory has strong negative valence (e.g. a past outage), salience weights shift dynamically so critical errors outrank recent trivia. Each result is classified as critical_warning, known_antipattern, or context.

Consolidation happens automatically in all server modes (MCP, REST, proxy) on a configurable timer (default 60s, set SMRTI_REFLECT_INTERVAL). Each cycle merges pending evidence via PLN Bayesian revision, decays attention, promotes high-importance nodes to long-term memory, resolves contradictions by weakening the less confident belief, and prunes low-salience atoms. You can also trigger it manually via reflect(). A personality profile (16 tunable hyperparameters) governs every weight and threshold in this pipeline.

Features

• Graph-structured memory — Concepts, beliefs, episodes, and goals as typed atoms with relation edges
• Bayesian truth maintenance — Probabilistic Logic Networks (PLN) for merging independent observations
• Personality-driven retrieval — 6 presets with 16 tunable hyperparameters that shape what gets surfaced
• Multi-tenant isolation — Tenant/space overlay model with cross-space reads and single-space writes
• Three server modes — MCP (stdio), REST API, and OpenAI-compatible proxy
• Entity resolution — 4-tier cascade: exact match, alias lookup, fuzzy (RapidFuzz), embedding similarity
• Zero external services — Single SQLite file with sqlite-vec for KNN search, ONNX embeddings on CPU

Install

pip install smrti

Quick Start

Python API

from smrti import Smrti

mem = Smrti(db_path="~/.smrti/memory.db", personality="balanced")

# Store memories
mem.remember("Alice prefers TypeScript", probability=0.9, valence=0.3)
mem.remember("The deploy pipeline is broken", probability=0.95, valence=-0.7)

# Recall by semantic similarity + salience
results = mem.recall("programming languages")
for r in results:
    print(f"{r.atom.label} (salience={r.salience:.2f}, confidence={r.atom.truth.confidence:.2f})")

# Assert a belief with evidence
mem.believe("Python is the best language for ML", probability=0.85, evidence="Team survey results")

# Consolidate: decay, promote, prune, resolve contradictions
epoch = mem.reflect()
print(f"Updated {epoch.beliefs_updated} beliefs, pruned {epoch.atoms_pruned} atoms")

mem.close()

CLI

# Initialize a database
smrti init --db ~/.smrti/memory.db --personality balanced

# Check status
smrti status

# Start servers
smrti serve mcp           # MCP stdio server (for Claude, etc.)
smrti serve rest           # FastAPI on :8420
smrti serve proxy          # OpenAI-compatible proxy on :8421

Server Modes

MCP Server

Exposes 6 tools over stdio for direct LLM integration (Claude, etc.):

Tool	Description
remember	Store an observation or episode
recall	Semantic search with salience scoring
believe	Assert a belief with truth value
reflect	Run a consolidation epoch
forget	Lower confidence on a memory
status	Get memory statistics

smrti serve mcp

Configure via environment variables:

export SMRTI_DB=~/.smrti/memory.db
export SMRTI_PERSONALITY=balanced
export SMRTI_TENANT_ID=default
export SMRTI_SPACE=default
export SMRTI_READ_SPACES=default,shared   # comma-separated
export SMRTI_REFLECT_INTERVAL=60          # auto-consolidation interval in seconds (0 to disable)

REST API

Full CRUD over HTTP on port 8420:

smrti serve rest --host 0.0.0.0 --port 8420

# Store a memory
curl -X POST http://localhost:8420/remember \
  -H "Content-Type: application/json" \
  -d '{"content": "Alice prefers TypeScript", "probability": 0.9}'

# Recall
curl -X POST http://localhost:8420/recall \
  -d '{"query": "programming languages", "top_k": 5}'

# Run consolidation
curl -X POST http://localhost:8420/reflect

# Get status
curl http://localhost:8420/status

OpenAI-Compatible Proxy

Drop-in replacement for https://api.openai.com/v1/chat/completions. Intercepts requests, injects relevant memories into the system prompt, and stores the exchange afterward.

smrti serve proxy --host 0.0.0.0 --port 8421 --upstream https://api.openai.com

Use it from any OpenAI-compatible client:

from openai import OpenAI

client = OpenAI(
    base_url="http://localhost:8421/v1",
    api_key="sk-..."  # forwarded to upstream
)

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "What do you know about Alice?"}],
    extra_headers={
        "X-Smrti-Tenant-Id": "user_123",
        "X-Smrti-Write-Space": "work",
        "X-Smrti-Read-Spaces": "work,personal",
    }
)

The proxy automatically:

1. Recalls relevant memories from the specified read spaces (using recent conversation context, not just the last message)
2. Classifies each memory by severity (critical_warning, known_antipattern, context) and injects them as structured XML tags into the system prompt
3. Stores user messages and the assistant response as episodes

Configure with:

export SMRTI_UPSTREAM_URL=https://api.openai.com  # or any OpenAI-compatible API
export SMRTI_RECALL_TOP_K=5
export SMRTI_RECALL_MIN_CONFIDENCE=0.3
export SMRTI_QUERY_MODE=concat        # "concat" (default) or "last" for last-message-only
export SMRTI_QUERY_CONTEXT_MSGS=5     # number of recent messages to include in query
export SMRTI_QUERY_MAX_CHARS=500      # max characters for the recall query
export SMRTI_REFLECT_INTERVAL=60      # auto-consolidation interval in seconds (0 to disable)

Multi-Tenant / Space Model

Smrti uses a two-level isolation model:

• Tenant — Hard boundary. Different tenants never share atoms. Maps to a user or organization.
• Space — Soft boundary within a tenant. Memories are written to one space but can be read from multiple.

# Read from multiple spaces, write to one
mem = Smrti(
    tenant_id="user_123",
    write_space="work",
    read_spaces=["work", "personal", "shared"]
)

# Each space can have its own personality
mem.set_personality("analytical")

Personality System

Six built-in presets control retrieval behavior, decay rates, and emotional dynamics:

Preset	Bias	Use Case
balanced	Equal weights across all signals	General-purpose agents
analytical	High confidence weight, low valence	Logical reasoning, data-driven decisions
curious	High STI weight, fast decay	Exploration, novelty-seeking
empathetic	High valence weight, emotional propagation	Relationship-focused agents
maverick	Slow decay, high propagation	Independent, contrarian reasoning
deterministic	Fast learning, slow decay, laser focus	Agentic workflows, code gen, deployments

Each preset tunes 16 hyperparameters. To create a custom personality, start from a preset and override individual values via the personality DB table or the /personality API endpoint.

Hyperparameter Reference

Salience weights — control how retrieval ranks results (should sum to ~1.0):

Parameter	Default	Effect
w_similarity	0.35	Weight of embedding cosine similarity
w_sti	0.25	Weight of short-term importance (recency/access)
w_confidence	0.20	Weight of truth value confidence
w_lti	0.10	Weight of long-term importance
w_valence	0.10	Weight of emotional intensity (dynamically boosted when valence < -0.5)

Belief dynamics — govern how confidence evolves over time:

Parameter	Default	Effect
confidence_decay_rate	0.02	Per-epoch confidence decay. Higher = memories fade faster
confidence_update_lr	0.3	Learning rate for PLN evidence merges. Higher = new evidence has more impact
min_confidence_to_surface	0.1	Floor below which atoms are excluded from recall results

Attention dynamics — control what stays in focus:

Parameter	Default	Effect
sti_decay_rate	0.1	Per-epoch STI decay. Higher = faster attention loss
sti_boost_on_access	0.5	STI added each time an atom is recalled. Higher = stronger recency bias
sti_propagation_factor	0.15	Fraction of STI boost propagated to linked atoms. Higher = broader activation
lti_promotion_threshold	0.7	Cumulative STI required to increment LTI. Higher = harder to become permanent

Emotional dynamics — shape how valence influences behavior:

Parameter	Default	Effect
valence_weight	0.2	Global scaling factor for emotional influence on salience
valence_propagation	0.1	Fraction of valence propagated to linked atoms during epochs
mood_inertia	0.8	Resistance to mood shifts (0 = reactive, 1 = stable)

Architecture

graph TD
    subgraph Facade
        S["Smrti<br/><small>remember · recall · believe · reflect · forget · status</small>"]
    end

    subgraph Servers
        MCP["mcp.py<br/><small>MCP stdio</small>"]
        REST["rest.py<br/><small>FastAPI :8420</small>"]
        PROXY["proxy.py<br/><small>OpenAI proxy :8421</small>"]
    end

    subgraph Core
        AS["AtomSpace"]
        DB["Database"]
        EMB["Embedder"]
        MOD["Models"]
    end

    subgraph Retrieval
        FAN["fan_out"]
        SAL["salience"]
        CLS["classify"]
    end

    subgraph Evolution
        EPO["epoch"]
        TRU["truth"]
        CON["connections"]
    end

    subgraph Extraction
        RES["resolve"]
        ALI["aliases"]
    end

    subgraph Storage
        SQL["SQLite + sqlite-vec<br/><small>multilingual-MiniLM-L12-v2 · 384d · ONNX CPU</small>"]
    end

    MCP & REST & PROXY --> S
    S --> Core & Retrieval & Evolution & Extraction
    Core & Retrieval & Evolution & Extraction --> SQL

Loading

Retrieval pipeline: Embed query → KNN over tenant partition → filter to read spaces → 1-hop graph expansion → salience scoring → top-k

Salience formula:

S = w_sim × similarity + w_sti × sti + w_conf × confidence + w_lti × lti + w_val × |valence| × intensity

When valence < -0.5, weight shifts dynamically from w_sti to w_val so critical errors outrank recent trivia.

Consolidation epoch (runs automatically every SMRTI_REFLECT_INTERVAL seconds, or manually via reflect()):

1. Process pending evidence via Bayesian update
2. Decay STI and confidence
3. Promote high-STI atoms to LTI
4. Resolve contradictions (weaken less confident belief)
5. Discover cross-domain connections (every 10th epoch)
6. Prune atoms below confidence/LTI floors

Data Model

Atom Type	Purpose	Example
concept	Reusable entities	"Alice", "Python", "OpenAI"
belief	Probabilistic facts	"Alice prefers TypeScript"
episode	Timestamped observations	"User asked about deployment"
goal	Desired states	"Finish the migration by Friday"
relation	Edges between atoms	Alice → works_at → Acme Corp

Each atom carries:

• TruthValue — probability [0,1] and confidence [0,1], merged via PLN revision
• AttentionValue — sti (short-term importance, decays fast) and lti (long-term, accumulates)
• Valence — emotional tone [-1,1] and intensity [0,1]

Testing

pytest tests/ -v

License

MIT