refactor(coding-agent): add runtime host for session switching closes #2024

packages/coding-agent/examples/sdk/13-session-runtime.ts

@@ -0,0 +1,49 @@
+/**
+ * Session Runtime Host
+ *
+ * Use the runtime host when you need to replace the active AgentSession,
+ * for example for new-session, resume, fork, or import flows.
+ *
+ * The important pattern is: after the host replaces the runtime, rebind any
+ * session-local subscriptions and extension bindings to `runtimeHost.session`.
+ */
+
+import { AgentSessionRuntimeHost, createAgentSessionRuntime, SessionManager } from "@mariozechner/pi-coding-agent";
+
+const bootstrap = {};
+const runtime = await createAgentSessionRuntime(bootstrap, {
+	cwd: process.cwd(),
+	sessionManager: SessionManager.create(process.cwd()),
+});
+const runtimeHost = new AgentSessionRuntimeHost(bootstrap, runtime);
+
+let unsubscribe: (() => void) | undefined;
+
+async function bindSession() {
+	unsubscribe?.();
+	const session = runtimeHost.session;
+	await session.bindExtensions({});
+	unsubscribe = session.subscribe((event) => {
+		if (event.type === "queue_update") {
+			console.log("Queued:", event.steering.length + event.followUp.length);
+		}
+	});
+	return session;
+}
+
+let session = await bindSession();
+const originalSessionFile = session.sessionFile;
+console.log("Initial session:", originalSessionFile);
+
+await runtimeHost.newSession();
+session = await bindSession();
+console.log("After newSession():", session.sessionFile);
+
+if (originalSessionFile) {
+	await runtimeHost.switchSession(originalSessionFile);
+	session = await bindSession();
+	console.log("After switchSession():", session.sessionFile);
+}
+
+unsubscribe?.();
+await runtimeHost.dispose();

packages/coding-agent/examples/sdk/README.md

@@ -1,6 +1,6 @@
 # SDK Examples
 
-Programmatic usage of pi-coding-agent via `createAgentSession()`.
+Programmatic usage of pi-coding-agent via `createAgentSession()` and `createAgentSessionRuntime()`.
 
 ## Examples
 
@@ -18,6 +18,7 @@ Programmatic usage of pi-coding-agent via `createAgentSession()`.
 | `10-settings.ts` | Override compaction, retry, terminal settings |
 | `11-sessions.ts` | In-memory, persistent, continue, list sessions |
 | `12-full-control.ts` | Replace everything, no discovery |
+| `13-session-runtime.ts` | Manage runtime-backed session replacement |
 
 ## Running