---
title: Multi-Agent Design Patterns
created: '2026-05-25'
updated: '2026-05-25'
type: concept
namespace: work
tags: [agent, architecture, system]
confidence: medium
sources:
  - wiki/concepts/executor-orchestrator.md
  - wiki/concepts/autonomous-agent-safety.md
  - wiki/concepts/agent-memory-architecture.md
related:
  - "[[concepts/executor-orchestrator]]"
  - "[[concepts/autonomous-agent-safety]]"
  - "[[concepts/agent-memory-architecture]]"
---

# Multi-Agent Design Patterns

Synthesis of recurring patterns across the personal-os multi-agent system
and related agent architectures. Distilled from [[concepts/executor-orchestrator]],
[[concepts/autonomous-agent-safety]], and [[concepts/agent-memory-architecture]].

## Pattern 1 — Orchestrator / Worker Split

**What:** One agent owns conversation state and decision authority
(orchestrator); spawns separate worker agents for discrete tasks.

**Why:** Tight coupling between conversational layer and execution layer
causes mid-task interruptions and breaks user flow. Separate concerns.

**In personal-os:** Eagle (orchestrator) → Executor (worker) via Zulip.
**In psychologist app:** Narrator (orchestrator/mediator) ← Analyst (worker).

**Key constraint:** Worker communicates only through structured messages;
orchestrator has the only escalation path to the human.

## Pattern 2 — Scope Boundary + Auto-Approve Table

**What:** Predefine which actions a worker may take autonomously and which
require escalation. Publish the table explicitly.

**Why:** Autonomous agents fail catastrophically when they expand scope
unexpectedly (see [[concepts/executor-security-incident]]). Explicit tables
make failure modes visible.

**Implementation:** Message-type-based approval table. Unknown message types
default to escalation, never to silent proceed.

| Risk Level | Agent Action |
|---|---|
| Low (read, build, test) | Auto-approve |
| Medium (write external, open PR) | Auto-approve with logging |
| High (comment on others, merge) | Always escalate |
| Unknown | Always escalate |

## Pattern 3 — Memory Layer Separation

**What:** Separate in-session state (working memory) from cross-session
knowledge (semantic memory) from immutable facts (procedural/episodic).

**Why:** Agents that blur these layers either hallucinate stable facts or
fail to retain important session-to-session knowledge.

**In personal-os:** status.md (working) / wiki pages (semantic) /
SCHEMA.md + vault-filling-guide (procedural). See [[concepts/agent-memory-architecture]].

**Pattern rule:** Never update semantic memory from within an active session.
Crystallize post-session. Never trust working memory as a source of truth
for facts (always re-derive from semantic layer at session start).

## Pattern 4 — Role Specialization over Generalization

**What:** Instead of one agent with a long system prompt covering all roles,
split into agents with narrow, non-overlapping responsibilities.

**Why:** LLMs produce better outputs when role context is tight. Conflated
roles lead to persona drift ("is it being analytical or empathetic right now?").

**In psychologist app:** Analyst stays in 3rd-person analytical mode;
Narrator stays in 1st-person user-facing mode. Neither crosses the boundary.

**Trade-off:** Coordination overhead (structured message passing between
agents). Worthwhile when roles genuinely conflict (analysis vs. empathy).

## Pattern 5 — Deterministic Algorithm for Predictable Steps

**What:** Identify steps that look like LLM tasks but are actually
deterministic (sequencing, routing, counting) and implement them as code,
not as LLM calls.

**Why:** LLMs are expensive and non-deterministic. Steps like "show next
question in list" do not benefit from LLM reasoning and introduce failure modes.

**Examples:**
- Question delivery in psychologist app: batch generated by Analyst,
  sequenced by UI algorithm — not an LLM call per question
- Approval table in Executor: code switch on message type, not LLM judgment
- Vault namespace routing: rules in tech/vault-namespace, not agent inference

## See Also

- [[concepts/executor-orchestrator]] — concrete orchestrator/worker implementation
- [[concepts/autonomous-agent-safety]] — safety checklist derived from incidents
- [[concepts/agent-memory-architecture]] — memory taxonomy for LLM agents
- [[entities/psychologist-app]] — dual-agent architecture (patterns 1 and 4)