Architecture

The CLI owns argument parsing, logging setup, top-level orchestration, and the process exit boundary. The library owns configuration parsing, module preparation, variable resolution, command construction, and workflow execution.

configuration (JSON or YAML)
            |
            v
        xylem-cli
            |
            v
        xylem-lib
       /    |     \
      v     v      v
 modules  inputs  variables
       \    |     /
        v   v    v
       child commands

ExecutionLimits and ExecutionContext provide the current worker-budget boundary. Modules execute in declaration order for an input, while multiple inputs and module preparation may use the configured Rayon pool.

See ARCHITECTURE.md for repository-level notes and the planning wiki for proposed contract changes.