Multi-Agent Architecture Patterns

Distribute work across multiple LM instances w/ isolated context windows. Sub-agents exist to isolate context, not to anthropomorphize roles.

When to Activate

• Single-agent context limits constrain task complexity
• Tasks decompose into parallel subtasks
• Different subtasks need different tools | system prompts
• Building multi-domain agent systems

Core Concepts

Three patterns: supervisor/orchestrator (centralized), peer-to-peer/swarm (flexible handoffs), hierarchical (layered abstraction). Key principle: context isolation — sub-agents partition context, not simulate org roles. Requires explicit coordination protocols & consensus mechanisms avoiding sycophancy.

Token Economics

Architecture	Token Multiplier	Use Case
Single agent	1x	Simple queries
Agent w/ tools	~4x	Tool-using tasks
Multi-agent	~15x	Complex research/coordination

BrowseComp: token usage explains 80% of performance variance. Model upgrades often outperform doubling token budgets — model selection & multi-agent architecture are complementary.

Parallelization

Tasks w/ independent subtasks: assign each to dedicated agent w/ fresh context. All work simultaneously -> total time approaches longest subtask, not sum of all.

Architectural Patterns

Pattern 1: Supervisor/Orchestrator

User Query -> Supervisor -> [Specialist, Specialist, Specialist] -> Aggregation -> Final Output

Use when: Clear decomposition, cross-domain coordination, human oversight needed Pros: Strict workflow control, easier human-in-the-loop Cons: Supervisor context bottleneck, cascade failures, "telephone game" problem

Telephone Game Fix: forward_message tool lets sub-agents pass responses directly to users:

def forward_message(message: str, to_user: bool = True):
    """Forward sub-agent response directly to user w/o supervisor synthesis."""
    if to_user:
        return {"type": "direct_response", "content": message}
    return {"type": "supervisor_input", "content": message}

Pattern 2: Peer-to-Peer/Swarm

Agents communicate directly via handoff mechanisms. No central control.

def transfer_to_agent_b():
    return agent_b  # Handoff via fn return

agent_a = Agent(name="Agent A", functions=[transfer_to_agent_b])

Use when: Flexible exploration, emergent requirements Pros: No single point of failure, scales for breadth-first exploration Cons: Coordination complexity grows w/ agent count, divergence risk

Pattern 3: Hierarchical

Strategy Layer (Goals) -> Planning Layer (Decomposition) -> Execution Layer (Atomic Tasks)

Use when: Large-scale projects, enterprise workflows, mixed high/low-level tasks Pros: Clear separation of concerns, different context per level Cons: Inter-layer coordination overhead, strategy-execution misalignment

Context Isolation

Primary purpose of multi-agent architecture. Three mechanisms:

• Full context delegation: Planner shares entire context -> max capability but defeats isolation purpose
• Instruction passing: Planner creates instructions via fn call -> maintains isolation, limits flexibility
• File system memory: Agents read/write persistent storage -> shared state w/o context bloat, adds latency

Consensus & Coordination

• Weighted voting: Weight by confidence/expertise (not simple majority)
• Debate protocols: Adversarial critique > collaborative consensus for complex reasoning
• Trigger-based intervention: Stall triggers (no progress), sycophancy triggers (mimicked answers)

Failure Modes

Failure	Mitigation
Supervisor bottleneck	Output schema constraints, workers return distilled summaries, checkpointing
Coordination overhead	Clear handoff protocols, batch results, async communication
Divergence	Objective boundaries per agent, convergence checks, TTL limits
Error propagation	Validate outputs before passing, retry w/ circuit breakers, idempotent ops

Examples

Supervisor
├── Researcher (web search, doc retrieval)
├── Analyzer (data analysis, statistics)
├── Fact-checker (verification)
└── Writer (report generation)

def handle_customer_request(request):
    if request.type == "billing":
        return transfer_to(billing_agent)
    elif request.type == "technical":
        return transfer_to(technical_agent)
    elif request.type == "sales":
        return transfer_to(sales_agent)
    else:
        return handle_general(request)

Guidelines

1. Design for context isolation as primary benefit
2. Choose pattern by coordination needs, not org metaphor
3. Explicit handoff protocols w/ state passing
4. Weighted voting | debate for consensus
5. Monitor supervisor bottlenecks, use checkpointing
6. Validate outputs between agents
7. Set TTL limits to prevent infinite loops
8. Test failure scenarios explicitly

Integration

Builds on context-fundamentals & context-degradation:

• memory-systems — shared state across agents
• tool-design — tool specialization per agent
• context-optimization — context partitioning strategies

References

• LangGraph — Multi-agent patterns & state management
• AutoGen — GroupChat & conversational patterns
• CrewAI — Hierarchical agent processes
• Multi-Agent Coordination Survey