Go modular bricks

Establish project rules first

Read the project's agent instructions and documented coding standards before selecting examples. Follow their pointers to affected interface contracts and accepted ADRs. Use the project's document paths, not assumed filenames. Record the local rules for ownership, errors, private functions, comments, wiring, and tests. These rules override generic recipes throughout the skill. Nearby code does not authorize a violation. Consult architecture exceptions for unresolved conflicts or undocumented departures.

Classify before choosing a package

For each new or extracted responsibility, state its behavior, owner, intended file, and selected contract before editing. For review, classify each affected responsibility before judging it. A requested name, existing package, receiver, number of callers, or use of I/O does not determine ownership.