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Choreography Is Not a Topology

Choreography is a coordination mode that operates across topologies, not one column among six. Closer to the Teams pattern than to Orchestrate's opposite.

Definition

In distributed systems, choreography names a way of coordinating agents without a central conductor: events propagate, peers react. When applied to AI agents, choreography can sit alongside chain / route / parallel / loop / hierarchy / orchestrate — it is a coordination mode, not an execution shape. Treating it as a seventh topology column would conflate two different kinds of axis.

The problem it names

[TODO: 咖哥 voice — 这一节最适合你写。 你在做双轴矩阵时,茹炳晟和姜宁都讨论过"编舞算不算独立拓扑"。 结论是"不算"——这件事值得在这里留个 record。 可以一句话讲清:编舞回答 "谁触发谁",拓扑回答 "工作长什么形状",问题层不同。]

How it changes design decisions

Once choreography is recognized as a coordination mode rather than a shape, design conversations get cleaner:

• You can have a fan-out/gather (Parallel) under choreography — workers react to a published event, no orchestrator dispatches them
• You can have a handoff chain (Chain) under choreography — each agent emits an event that the next subscribes to
• The matrix stays 7×6; the choreography choice is a cross-cutting decision documented per-pattern, not a new column

This mirrors the older Teams pattern (PLOPD): teams describe how peers coordinate; pipelines / hierarchies describe how work flows. Different axes.

Lineage

• Saga pattern (Garcia-Molina & Salem, 1987) — distributed transactions via choreographed event flow
• Choreography vs orchestration debate in microservices (early 2010s) — same architectural question, agent era inherits it
• Event Sourcing / CQRS — choreography as the dominant coordination mode in event-driven systems
• Teams pattern (PLOPD vol. 3, 1995) — peer coordination as a distinct architectural concern

What it is NOT

• Not "Orchestrate's opposite." Treating them as a binary flattens the matrix.
• Not a sixth or seventh topology column. The matrix already names six shapes; choreography crosses all six.
• Not "leaderless multi-agent." Choreography is a coordination protocol; leaderless is one consequence among several.
• Not absent from the framework. The choice surfaces in the per-pattern text where it matters (e.g. Collaboration patterns), it just doesn't get its own column.

Where it's developed further

• ADPS Collaboration module (C1-C5): each pattern's white paper notes when choreography is the right mode vs orchestration
• Note appears below the matrix on both adpsagent.com/patterns/ and the kage-ai dual-axis page
• Position paper: arXiv:2605.13850 — explicit treatment of why choreography sits outside the topology axis

Cite as: Huang, J. (2026). Choreography Is Not a Topology. kage-ai.com/concepts/choreography-is-not-a-topology/