Add CUA AgentHarness model switching

Author: rgarcia

docs/architecture.md

@@ -41,7 +41,7 @@ someone who wants to read the code, contribute, or fork.
   - provider payload transforms and protocol quirks (for example, Yutori tool serialization policy)
   - canonical CUA tool-definition exports
 - `@onkernel/cua-agent` owns browser execution orchestration:
-  - `CuaAgent` / `CuaHarness` class wiring around `pi-agent-core`
+  - `CuaAgent` / `CuaAgentHarness` class wiring around `pi-agent-core`
   - executing canonical CUA tool calls against Kernel browsers
   - typed executor coverage and translator integration
 

packages/agent/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 0.1.0
 
-- Class-first CUA runtime: `CuaAgent` and `CuaHarness` on top of pi-agent-core.
+- Class-first CUA runtime: `CuaAgent` and `CuaAgentHarness` on top of pi-agent-core.
+- `CuaAgent` and `CuaAgentHarness` refresh CUA runtime defaults when models change.
 - Provider-neutral browser tool executors for canonical CUA tool names, backed by Kernel browser actions.
 - Includes examples plus unit and live e2e coverage for common provider/model combinations.

packages/agent/README.md

@@ -33,12 +33,12 @@ const agent = new CuaAgent({
 await agent.prompt("Open news.ycombinator.com and summarize the top story.");
 ```
 
-## Quick Start (`CuaHarness`)
+## Quick Start (`CuaAgentHarness`)
 
 ```ts
-import { CuaHarness } from "@onkernel/cua-agent";
+import { CuaAgentHarness } from "@onkernel/cua-agent";
 
-const harness = new CuaHarness({
+const harness = new CuaAgentHarness({
   browser,
   client,
   model: "openai:gpt-5.5",
@@ -54,17 +54,15 @@ lifecycle events, custom streaming, and explicit prompt/continue/queue control.
 Reach for the harness shape when you want an app layer around the loop:
 session/transcript helpers, resource and prompt entry points, provider/auth
 hooks, active tool selection, compaction/tree workflows, and higher-level queue
-events. `CuaHarness` is the thin CUA version of that shape today: it installs
-CUA defaults, delegates runtime methods to the wrapped `Agent`, and adds
-`getTranscript()`.
+events. `CuaAgentHarness` extends pi `AgentHarness`, installs CUA defaults, and
+refreshes provider-specific runtime state when `setModel()` changes models.
 
 ## Core Concepts
 
 ### Class-First API
 
 - `CuaAgent extends Agent`
-- `CuaHarness` wraps a pi `Agent` with a harness-style constructor and
-  delegated runtime methods.
+- `CuaAgentHarness extends AgentHarness`
 
 Both classes mirror pi constructor shapes and behavior, with minimal additions:
 - `browser` (Kernel browser response)
@@ -84,6 +82,17 @@ If tools are omitted, the classes install canonical CUA computer tool executors
 using runtime specs from `@onkernel/cua-ai`. If tools are provided, they are
 used exactly.
 
+### Model Switching
+
+`CuaAgent` follows pi `Agent` semantics: assign `agent.state.model` to a
+concrete model or CUA model ref. CUA-owned tools and the default system prompt
+refresh with the new provider runtime.
+
+`CuaAgentHarness` follows pi `AgentHarness` semantics: call
+`await harness.setModel(model)`. The harness updates its model through pi's
+snapshot machinery and refreshes CUA-owned tools and default prompt state for
+the next provider request.
+
 ### Tool Composition
 
 Use `createCuaComputerTools()` to compose your own tool list from canonical

packages/agent/examples/harness-openai-smoke.ts

@@ -1,6 +1,6 @@
 import Kernel from "@onkernel/sdk";
 import { requireCuaEnvApiKeyForModel, type CuaModelRef } from "@onkernel/cua-ai";
-import { CuaHarness } from "../src/index";
+import { CuaAgentHarness } from "../src/index";
 import { SCENARIOS } from "./shared/scenarios";
 
 const modelRef = (process.env.MODEL_REF as CuaModelRef | undefined) ?? "openai:gpt-5.5";
@@ -13,7 +13,7 @@ async function main(): Promise<void> {
 	const browser = await client.browsers.create({ stealth: true });
 
 	try {
-		const harness = new CuaHarness({
+		const harness = new CuaAgentHarness({
 			browser,
 			client,
 			model: modelRef,

packages/agent/examples/harness-provider-matrix.ts

@@ -1,6 +1,6 @@
 import Kernel from "@onkernel/sdk";
 import { requireCuaEnvApiKeyForModel, type CuaModelRef } from "@onkernel/cua-ai";
-import { CuaHarness } from "../src/index";
+import { CuaAgentHarness } from "../src/index";
 import { SCENARIOS } from "./shared/scenarios";
 
 const modelRef = (process.env.MODEL_REF as CuaModelRef | undefined) ?? "openai:gpt-5.5";
@@ -15,7 +15,7 @@ async function main(): Promise<void> {
 	const scenario = SCENARIOS.find((entry) => entry.name === scenarioName) ?? SCENARIOS[0]!;
 
 	try {
-		const harness = new CuaHarness({
+		const harness = new CuaAgentHarness({
 			browser,
 			client,
 			model: modelRef,