# When to Split Into Multiple Agents

Companion to **When Does an eCommerce Business Need Multiple AI Agents?**

Default: **one** agent. Multi-agent is a cost and failure-mode multiplier. Strands Graph / Swarm / Agents-as-Tools are **framework** patterns on Runtime after export — they do not replace Gateway, Identity, or Cedar.

```text
Operations Supervisor (only if needed)
        │
   ┌────┼────┐
   ↓    ↓    ↓
 Sales Inv. Support
```

## Decision

| Situation | Choose |
| --------- | ------ |
| One domain, ≤~8 tools, one Identity audience | **One** Harness |
| Deterministic path (status → template) | **Workflow / Flow**, not an agent |
| Two domains, different write blast radius | Two agents **or** one agent with tool allow-lists per JWT |
| Cross-domain question with hop caps / specialists | Supervisor + specialists (export to Strands) |
| Vendor demo of Swarm | Still one agent until Level 4 works |

## Failure modes of premature multi-agent

- Duplicate tool calls; no hop cap
- Specialist A writes; specialist B unaware
- Shared Memory as a shadow CRM
- Swarm exploration on refunds

## Related

- Maturity: [`ai-agent-maturity-model.md`](ai-agent-maturity-model.md)
- Team roster: [`supervisor-specialist-team.md`](supervisor-specialist-team.md)
- CTO architecture: [`architecture-cto-brief.md`](architecture-cto-brief.md)