Skip to content

# Why One Agent Is Not Enough ​

June 3, 2026

A single agent, no matter how smart, hits three ceilings.

## The Context Ceiling ​

One agent doing everything means one context window holding everything. File contents, database schemas, business logic, deployment configs — they all compete for the same limited space. A 100K token codebase leaves zero room for the actual task.

## The Capability Ceiling ​

A generalist agent is mediocre at everything. A specialized agent — backend dev, security reviewer, UI designer — outperforms the generalist in its domain by a wide margin. You wouldn't ask your frontend dev to write SQL migrations. Why ask your agent to?

## The Reliability Ceiling ​

One agent failing = everything fails. Multi-agent systems degrade gracefully. If the reviewer agent crashes, the builder keeps working. If the planner goes down, deployed agents continue running.

## The Solution: Depth-2 Delegation ​

The production-proven pattern:

    User
      |
      v
    Orchestrator (Opus-level, thinking only)
      |
      +-- Planning Team Lead
      |     +-- Product Manager (worker)
      |     +-- UX Researcher (worker)
      |
      +-- Engineering Team Lead
      |     +-- Frontend Dev (worker)
      |     +-- Backend Dev (worker)
      |
      +-- Validation Team Lead
            +-- QA Engineer (worker)
            +-- Security Reviewer (worker)

Leads think, plan, and delegate. Workers execute. The orchestrator never touches code.

## When to Go Multi-Agent ​

You need multiple agents when any of these are true:

- Different expertise required — Your task needs a planner, a coder, a reviewer, and a security auditor
- Parallel work possible — Multiple sub-tasks can run simultaneously
- Failure cost is high — You want a second agent to catch mistakes before they ship
- Context exceeds one window — Split across specialized agents

If none of these are true, a single well-configured agent is simpler and cheaper.

This is an excerpt from Module 4 of the Agentic Engineering Course. The full module includes runnable lab code for building multi-agent systems with domain locking, mental models, and P2P communication.