Composable
n.—value that comes from the joint, not the parts.
A high-performance tyre is a composite whose behaviour comes from an architecture of rubber compounds, textile plies, steel cords, beads, and reinforcements. Each material has a distinct job: grip, stiffness, flexibility, containment, resistance to heat and fatigue. None could make a tyre on its own. Performance emerges from the way they are arranged, bonded, and made to work under load as a single object.
A composite is therefore not the sum of its ingredients. Steel cord alone cannot grip the road. Rubber alone cannot preserve the tyre's shape at speed. Textile reinforcement alone cannot transmit torque or hold a curve. Their limits do not disappear in the finished object; they are made useful by the structure that connects them.
That's the part of "composable" that the software usage of the word tends to lose. We use it to mean: small pieces that can be reassembled in different configurations. True, but incomplete. The configuration is not incidental—it's where the value actually lives. A skill, an MCP server, a well-scoped API: none of them are valuable in isolation. They become valuable in the specific way they're laid against each other, the same way the materials of a tyre become useful only once someone designs the architecture that holds them together.
I think about this every time someone frames modularity as the goal. Modularity is necessary but not sufficient—a box of well-cut parts is not a composite, it's a kit. The craft is in the assembly, not the cutting. An organization that gets very good at producing reusable components and never gets good at composing them has built a warehouse, not a material.