Canon

The canon is the methodology itself, in plain Markdown. Two complementary references — both required reading if you want to use FCD seriously, but each useful on its own.

FCA — Fractal Component Architecture

The structural layer. Defines what a component is, how components compose, and how the same discipline repeats at every scale of software.

Eight chapters take you from the 8-part component model through layers, domains, FP roots, the 10 principles, common patterns, and a fully worked applied example. Three advice documents cover multiagent systems, co-design dynamics, and recursive semantic algorithms.

Start here: 01 — The Component.

ECD — Extreme Co-Design

The process layer. Defines how teams make FCA tractable in practice: surface-first ordering, port freezes, co-design rituals.

Three chapters: the philosophy and evidence, the translation from hardware co-design to software engineering, and the synthesis that shows how FCA operationalizes ECD’s principles.

Start here: 01 — Extreme Co-Design.

How the canon is used

• By the fcd-* Claude skills — each skill loads or references canon sections to inform agent behavior. The skills are the canon-in-action.
• By this docs site — the markdown rendered here is the same markdown stored in canon/ at the repo root. There is no duplication.
• By tools — @fractal-co-design/fca-index (and future tools) implement canon concepts (8-part components, port detection, layer assertions).

Contributing

Substantive changes (new principles, restructured part model) need discussion via issue first — canon is the spec everything else depends on. Typo fixes and clarifications via PR. See CONTRIBUTING.md.