Vol. II · Production Doctrine · II.5
Small, Focused Agents
A good agent has few tools, a narrow goal, and a short context. Generalists are orchestrators. Specialists do the work.
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humanlayer/12-factor-agentsopenai/openai-agents-pythonlangchain-ai/deepagentscrewAIInc/crewAIopenai/swarm
Doctrine
- If an agent has more than a handful of tools, split it.
- Subagents exist to protect the parent's context, not to add drama.
- Name agents after jobs, not after vibes: InvoiceMatcher, not Genius.
Factor 10 and the industry consensus
OpenAI Swarm/Agents SDK: hand off to a specialist. Deep Agents: spawn a subagent with a fresh window and a file drop. CrewAI: one role, one goal, one backstory — and the backstory is only useful if it changes behavior. DeerFlow: researcher ≠ coder ≠ publisher.
The scaling law that matters is not number of agents. It is number of tokens each agent must keep coherent. Small agents are a context strategy.
Anti-patterns
- One agent with browser, shell, email, database, and 'search the web'.
- Role-play backstories that do not change the tool set or the prompt constraints.
- Spawning subagents that inherit the full parent transcript.