Patterns & control flow

Composition, delegation, visibility, memory — how multiple agents cooperate without stepping on each other.

        flowchart LR
    P[Patterns<br/>review_loop, map_reduce,<br/>cascade, fan_out_merge] --> T[Transfer control<br/>sub_agent vs agent_tool]
    T --> V[Visibility<br/>what surfaces in<br/>the topology]
    V --> M[Memory<br/>persistence across<br/>sessions]

    classDef node fill:#ede7f6,stroke:#4527a0,color:#311b92
    class P,T,V,M node
    

Chapters

Chapter	Reach for it when
Patterns	You’re writing the same compose-shape for the third time — use a higher-order constructor instead.
Transfer control	You need to delegate to a specialist — and you’re unsure whether to call it as a tool or hand off control.
Visibility	Your topology diagram or audit log is cluttered with plumbing agents.
Memory	You need continuity beyond one session — user preferences, past conversations, long-term state.

Know the builders first — start with Foundations if you haven’t.

Tip

Pattern or raw builder? Higher-order patterns (review_loop, map_reduce) are syntactic sugar over Pipeline / Loop / FanOut. Start with the raw builder; reach for a pattern only when you’ve written the same shape twice. Patterns encode conventions, not capabilities.