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Memory Architectures

This guide covers architectural patterns for using Z3rno’s four-tier memory system effectively. The core pattern is progressive consolidation: working memory flows into episodic memory, which is distilled into semantic memory, which informs procedural memory.

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The Consolidation Pipeline

Working Memory          Episodic Memory          Semantic Memory         Procedural Memory
(active context)        (event history)          (facts & knowledge)     (learned behaviours)
      |                       |                        |                        |
      |   session ends        |   pattern detected     |   behaviour learned    |
      |---------------------> |----------------------> |----------------------> |
      |                       |                        |                        |
   ephemeral              time-bounded              long-lived               permanent
   (minutes)              (days/weeks)              (indefinite)             (indefinite)
This mirrors how human memory works: short-term experiences are consolidated into episodic memories during sleep, repeated experiences become semantic knowledge, and practiced skills become procedural habits.

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Pattern 1: Automatic Session Consolidation

The simplest pattern. Z3rno automatically consolidates working memories into episodic memories when a session ends. 
from z3rno import Z3rnoClient

client = Z3rnoClient(base_url="http://localhost:8000", api_key="z3rno_sk_...")

# Start a session
session = client.start_session(agent_id="support-agent")

# During the conversation, store working memories
client.store(
    agent_id="support-agent",
    content="User asked about refund policy for annual plans.",
    memory_type="working",
    session_id=session.id,
)
client.store(
    agent_id="support-agent",
    content="User has order ORD-4821, purchased 3 days ago.",
    memory_type="working",
    session_id=session.id,
)
client.store(
    agent_id="support-agent",
    content="Issued full refund. User was satisfied with resolution.",
    memory_type="working",
    session_id=session.id,
)

# End session: working memories are consolidated into episodic
client.end_session(session_id=session.id)
# Result: An episodic memory is created summarizing the refund interaction
After the session ends, the working memories are evicted and a consolidated episodic memory is created. The next time someone asks “has this user contacted support?”, the episodic memory will surface.

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Pattern 2: Episodic-to-Semantic Promotion

When you notice the same fact appearing across multiple episodes, promote it to semantic memory for faster, more reliable recall. 
# After noticing a pattern across multiple interactions...
# The user has mentioned Python preference in 4 separate conversations.

# Option A: Explicit promotion via API
client.promote(
    memory_id="mem_episodic_xyz",
    target_type="semantic",
)

# Option B: Store directly as semantic when confidence is high
client.store(
    agent_id="support-agent",
    content="User is a Python developer who prefers CLI tools over GUIs.",
    memory_type="semantic",
    importance=0.85,
    metadata={"derived_from": ["mem_ep_1", "mem_ep_2", "mem_ep_3", "mem_ep_4"]},
)

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Automated Pattern Detection

Build a periodic job that scans episodic memories for repeated themes: 
def consolidate_episodes(agent_id: str):
    """Scan recent episodes and extract semantic facts."""
    from openai import OpenAI
    oai = OpenAI()

    # Get recent episodic memories
    episodes = client.recall(
        agent_id=agent_id,
        query="*",
        memory_type="episodic",
        top_k=50,
    )

    if len(episodes.results) < 5:
        return  # Not enough data to consolidate

    # Use an LLM to extract recurring facts
    episode_text = "\n".join(f"- {r.content}" for r in episodes.results)

    completion = oai.chat.completions.create(
        model="gpt-4o",
        messages=[{
            "role": "system",
            "content": "Extract recurring facts, preferences, and patterns from these interaction summaries. Return each fact on its own line. Only include facts that appear in multiple interactions.",
        }, {
            "role": "user",
            "content": episode_text,
        }],
    )

    facts = completion.choices[0].message.content.strip().split("\n")
    for fact in facts:
        if fact.strip():
            client.store(
                agent_id=agent_id,
                content=fact.strip(),
                memory_type="semantic",
                metadata={"source": "episode_consolidation"},
            )

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Pattern 3: Procedural Learning

Extract behavioural patterns from successful interactions and store them as procedural memories. 
def learn_procedure(agent_id: str, pattern: str, confidence: float = 0.7):
    """Store a learned behaviour as procedural memory."""
    client.store(
        agent_id=agent_id,
        content=pattern,
        memory_type="procedural",
        importance=confidence,
        metadata={"type": "learned_behaviour"},
    )

# After observing that empathetic responses get higher satisfaction scores:
learn_procedure(
    "support-agent",
    "When a user is frustrated, acknowledge their frustration explicitly before offering a solution. Example: 'I understand this is frustrating. Let me help fix this right away.'",
    confidence=0.85,
)

# After observing that step-by-step responses work better for technical questions:
learn_procedure(
    "support-agent",
    "For technical troubleshooting questions, provide numbered step-by-step instructions rather than paragraph explanations.",
    confidence=0.9,
)

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Using Procedural Memory in Responses

def get_response_guidelines(agent_id: str, question: str) -> str:
    """Recall procedural memory to guide response generation."""
    response = client.recall(
        agent_id=agent_id,
        query=question,
        memory_type="procedural",
        top_k=3,
    )
    if response.results:
        return "\n".join(f"- {r.content}" for r in response.results)
    return ""

# Include procedural guidance in the system prompt
guidelines = get_response_guidelines("support-agent", "User is frustrated about billing")
system_prompt = f"""You are a support agent. Follow these learned guidelines:
{guidelines}
"""

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Pattern 4: Full-Stack Memory Architecture

Combine all tiers into a complete memory system: 
class AgentMemory:
    """Full-stack memory architecture using all four tiers."""

    def __init__(self, client: Z3rnoClient, agent_id: str):
        self.client = client
        self.agent_id = agent_id

    def build_context(self, query: str) -> dict:
        """Build a comprehensive context from all memory tiers."""

        # Procedural: How should I respond?
        procedures = self.client.recall(
            agent_id=self.agent_id,
            query=query,
            memory_type="procedural",
            top_k=3,
        )

        # Semantic: What do I know?
        facts = self.client.recall(
            agent_id=self.agent_id,
            query=query,
            memory_type="semantic",
            top_k=5,
        )

        # Episodic: What has happened before?
        episodes = self.client.recall(
            agent_id=self.agent_id,
            query=query,
            memory_type="episodic",
            top_k=5,
        )

        # Working: What is happening right now?
        working = self.client.recall(
            agent_id=self.agent_id,
            query=query,
            memory_type="working",
            top_k=10,
        )

        return {
            "guidelines": [r.content for r in procedures.results],
            "facts": [r.content for r in facts.results],
            "history": [r.content for r in episodes.results],
            "current_context": [r.content for r in working.results],
        }

    def format_system_prompt(self, context: dict) -> str:
        """Format memory context into a system prompt section."""
        parts = []
        if context["guidelines"]:
            parts.append("## Response Guidelines\n" + "\n".join(f"- {g}" for g in context["guidelines"]))
        if context["facts"]:
            parts.append("## Known Facts\n" + "\n".join(f"- {f}" for f in context["facts"]))
        if context["history"]:
            parts.append("## Relevant History\n" + "\n".join(f"- {h}" for h in context["history"]))
        if context["current_context"]:
            parts.append("## Current Session\n" + "\n".join(f"- {c}" for c in context["current_context"]))
        return "\n\n".join(parts)

# Usage
memory = AgentMemory(client, "support-agent")
context = memory.build_context("User asking about refund")
prompt_section = memory.format_system_prompt(context)

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Architecture Decision Guide

ScenarioRecommended Architecture
Simple chatbot with historySession consolidation only (Pattern 1)
Personal assistant that learnsSession + episodic-to-semantic (Patterns 1+2)
Customer support agentFull-stack with procedural learning (Pattern 4)
Research agentEpisodic + semantic without procedural (Patterns 1+2)
Multi-agent crewShared semantic + private working (see Multi-Agent Memory)

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Next Steps