Collapsing a multi-subagent architecture into a single 'smart main agent' with efficient tool calling was the primary lever for a 90-95% cost reduction — the cost driver was token overhead from agent nesting, not model choice or prompt quality.
It reframes multi-agent decomposition as a cost/latency liability rather than a capability upgrade, and points to the agent-boundary (separate model loop vs. tool call inside one loop) as the highest-leverage cost knob in an agentic system.
Any agentic system that spawns subagents should be able to justify each nested model loop against the token cost of context re-establishment; the default should be tool calls within one main loop until proven otherwise.
Running numerous subagents proved too expensive.
Moving to a smarter main agent reduced costs by 90-95%.
Subagents create massive token overhead and cost escalation.