# agent_appkit The macOS GUI backend for the [agent surface](/docs/agent-surface): it binds the framework-agnostic [agent_core](/docs/packages/agent_core) rules to a live [AppKit](/docs/packages/appkit) window. - **`open(window)`** walks the live NSView tree into a `Surface` — the controllable model an agent sees. - **`describe_ui`** returns a snapshot of the exposed nodes (`Vec[UiNode]`). A node is exposed by giving it an agent id with `set_agent_id`. - **Authorized actions** — `click`, `set_text`, and `scroll_to` run through the `agent_core` authorization brain. Text edits use optimistic-concurrency versioning, so a stale edit is rejected. - **Events** — AppKit notifications are translated into verbs and delivered as the bubbling events `agent_core` defines. Pair it with [agent_mcp](/docs/packages/agent_mcp) to expose the surface to an external agent. [AppKit agent surface](/examples/appkit-agent-counter) documents the checked `docs/examples/recipes/appkit_agent` recipe from the C+ source tree: describe the tagged UI, act on a real AppKit button, reject stale text edits, and refuse requests through a closed consent gate.