what we build · part four
Technical Shaping
The system's flow as a parallel discipline to the user's flow. Sequence diagrams, schemas, API contracts, ADRs, ilities. Same just-in-time pull, same release-1-first scope. Where infrastructure work belongs in the chain.
Events in this phase. Daily continues. Tech-lead-led conversations on the schema and API contracts, often pulling in the developer who will implement. ADRs are written when decisions surface that constrain future code.
What technical shaping does
Design shaping produces flows the user travels. Technical shaping produces flows the system travels. Both happen in parallel during the same window — for the same set of release-1 stories. Neither leads the other; both inform the story as it takes shape.
Technical shaping has its own artifacts. Sequence diagrams trace the path a request takes through services. Schemas describe the shape data takes in storage. API contracts define what one service promises to another. Architecture Decision Records (ADRs) capture choices that constrain future code. Each is a translation of the brief into a technical shape — and each can carry the brief's meaning forward, or quietly substitute the technical defaults the team had on hand.
The artifacts named in this part are not the whole of technical practice. There is also system architecture at higher altitude — how services compose, where boundaries fall, how the team's work fits the larger platform. Frameworks like C4 and arc42 provide vocabulary for drawing these views; senior engineers should know at least one. There is domain modelling — the conceptual entities the system reasons about, distinct from the physical schema that stores them. There is infrastructure and platform — the runtime, the deployment topology, the observability stack. This volume's scope is the chain at the unit-of-work level: the artifacts that travel from a signed brief into a story ready to pull. Architecture, modelling, and platform are upstream concerns whose decisions enter this chain through ADRs and ilities. The depth of those crafts lives in their own literature.
To make this concrete, this part walks through Uri's billing case from Volume II — the seven months of silent Cardcom failures, the manual reconciliation, the trust deficit. The Epic has been named: "Run a clean billing cycle without manual reconciliation." Uri is named in the Epic description — the person from the Technical Design Brief whose situation changes. Now technical shaping begins.