NorthCUA Harness architecture

The NorthCUA repository currently packages the NorthCUA Harness. The following components implement its Desktop/Web task lifecycle on public NexAU.

flowchart LR
  U[CLI / Python / websocket] --> A[Desktop or Web agent]
  A --> C[Context + image window + working memory]
  C --> N[Public NexAU model runtime]
  N --> T[Typed tool dispatch]
  T --> L[Local native / Playwright backend]
  T --> R[Controller command transport]
  R --> D[Leased device worker]
  A --> F[Durable artifacts]
  F --> E[Artifact / live evaluator]
  E --> L
  E --> R
  B[Batch scheduler] --> R
  B --> S[Fresh / task-prepared sandbox]
  S --> D

The protocol distribution defines task/session/command/artifact contracts. The shared runtime distribution defines tool schemas and backend bridges. The device distribution executes permitted commands. The root distribution owns agents, controller plugins, context/evaluation and orchestration; its desktop bridge is an explicit device dependency.

agentkernel contains policy/data abstractions; agentinfra connects NexAU, providers, context persistence and runtime infrastructure; agentkit composes reusable agent and evaluator execution. Desktop and Web specialize observations and actions. These layers are retained because the runnable paths and extension contracts depend on them.

NexAU adapters preserve NorthCUA's message, error, tracer and session contract on top of the pinned public runtime. Some compatibility hooks affect agent creation/history. Removing them is a behavioural change and requires the focused provider, lifecycle and history tests. The old private/public migration approval framework is not part of the runtime.

A controller lease defines which worker/session may execute commands. Task cancellation and cleanup stay distinct from terminal task decisions. The actor browser remains live through evaluation, then closes once. Prepared sandboxes belong to a task attempt; capacity is never recycled as hidden cross-task application state.

The retained nexau_compat layer has no private dependency. It defines explicit XML formatting, request/replay normalization, error-history and persistence behavior over public NexAU. Some internal symbols retain historical names. The old migration administration, duplicate CLI registry and unused visual planner have been removed; the generated AgentKit CLI and actual message projector are the maintained paths.