diff --git a/src/lib/onboard.ts b/src/lib/onboard.ts
index 4fef39b2aa..a05c9f16da 100644
--- a/src/lib/onboard.ts
+++ b/src/lib/onboard.ts
@@ -6382,6 +6382,7 @@ const onboardRuntimeBoundary = new OnboardRuntimeBoundary({
   maybeForceE2eStepFailure,
 });
 
+const recordOnboardStarted = onboardRuntimeBoundary.recordOnboardStarted.bind(onboardRuntimeBoundary);
 const startRecordedStep = onboardRuntimeBoundary.startRecordedStep.bind(onboardRuntimeBoundary);
 const recordStepComplete = onboardRuntimeBoundary.recordStepComplete.bind(onboardRuntimeBoundary);
 const recordStepSkipped = onboardRuntimeBoundary.recordStepSkipped.bind(onboardRuntimeBoundary);
@@ -6675,6 +6676,8 @@ async function onboard(opts: OnboardOptions = {}): Promise<void> {
       );
     }
 
+    await recordOnboardStarted(resume);
+
     // Backstop for the resume path: a session may exist (so the early guard
     // skipped because resume === true) but never have recorded a sandboxName
     // — sandbox creation could have failed before that step ran. Without a
diff --git a/src/lib/onboard/runtime-boundary.test.ts b/src/lib/onboard/runtime-boundary.test.ts
new file mode 100644
index 0000000000..d81116ed86
--- /dev/null
+++ b/src/lib/onboard/runtime-boundary.test.ts
@@ -0,0 +1,94 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { describe, expect, it } from "vitest";
+
+import {
+  createSession,
+  filterSafeUpdates,
+  normalizeSession,
+  type Session,
+  type SessionUpdates,
+} from "../state/onboard-session";
+import type { OnboardMachineEvent } from "./machine/events";
+import { OnboardRuntime, type OnboardRuntimeDeps } from "./machine/runtime";
+import { OnboardRuntimeBoundary } from "./runtime-boundary";
+
+function cloneSession(session: Session): Session {
+  return normalizeSession(JSON.parse(JSON.stringify(session))) ?? session;
+}
+
+function createRuntimeHarness() {
+  let session: Session | null = createSession();
+  const events: OnboardMachineEvent[] = [];
+  const updateSession = (mutator: (value: Session) => Session | void): Session => {
+    const current = session ? cloneSession(session) : createSession();
+    session = cloneSession(mutator(current) ?? current);
+    return cloneSession(session);
+  };
+  const deps: OnboardRuntimeDeps = {
+    loadSession: () => (session ? cloneSession(session) : null),
+    createSession,
+    saveSession: (next) => {
+      session = cloneSession(next);
+      return cloneSession(session);
+    },
+    updateSession,
+    markStepStarted: (stepName) =>
+      updateSession((current) => {
+        current.steps[stepName].status = "in_progress";
+        return current;
+      }),
+    markStepComplete: (stepName, updates: SessionUpdates = {}) =>
+      updateSession((current) => {
+        current.steps[stepName].status = "complete";
+        Object.assign(current, filterSafeUpdates(updates));
+        return current;
+      }),
+    markStepSkipped: (stepName) =>
+      updateSession((current) => {
+        current.steps[stepName].status = "skipped";
+        return current;
+      }),
+    markStepFailed: (stepName, message) =>
+      updateSession((current) => {
+        current.steps[stepName].status = "failed";
+        current.failure = { step: stepName, message: message ?? null, recordedAt: "now" };
+        return current;
+      }),
+    completeSession: (updates: SessionUpdates = {}) =>
+      updateSession((current) => {
+        Object.assign(current, filterSafeUpdates(updates));
+        current.status = "complete";
+        return current;
+      }),
+    filterSafeUpdates,
+    emitEvent: (event) => events.push(event),
+    now: () => "2026-05-27T00:00:00.000Z",
+  };
+  return {
+    createRuntime: () => new OnboardRuntime(deps),
+    events,
+  };
+}
+
+describe("OnboardRuntimeBoundary", () => {
+  it("records started and resumed lifecycle events through the runtime", async () => {
+    const harness = createRuntimeHarness();
+    const boundary = new OnboardRuntimeBoundary({
+      toSessionUpdates: (updates) => filterSafeUpdates(updates as SessionUpdates) as SessionUpdates,
+      maybeForceE2eStepFailure: () => undefined,
+      createRuntime: harness.createRuntime,
+    });
+
+    await boundary.recordOnboardStarted(false);
+    await boundary.recordOnboardStarted(true);
+
+    expect(harness.events.map((event) => event.type)).toEqual([
+      "onboard.started",
+      "onboard.resumed",
+    ]);
+    expect(harness.events[0]).toMatchObject({ state: "init" });
+    expect(harness.events[1]).toMatchObject({ state: "init" });
+  });
+});
diff --git a/src/lib/onboard/runtime-boundary.ts b/src/lib/onboard/runtime-boundary.ts
index daa8a13367..e90166e17b 100644
--- a/src/lib/onboard/runtime-boundary.ts
+++ b/src/lib/onboard/runtime-boundary.ts
@@ -8,6 +8,7 @@ import type { OnboardMachineEventType, OnboardMachineState } from "./machine/typ
 export interface OnboardRuntimeBoundaryOptions {
   toSessionUpdates(updates: Record<string, unknown>): SessionUpdates;
   maybeForceE2eStepFailure(stepName: string): void;
+  createRuntime?(): OnboardRuntime;
 }
 
 export class OnboardRuntimeBoundary {
@@ -16,7 +17,7 @@ export class OnboardRuntimeBoundary {
   constructor(private readonly options: OnboardRuntimeBoundaryOptions) {}
 
   reset(): void {
-    this.runtime = new OnboardRuntime();
+    this.runtime = this.options.createRuntime?.() ?? new OnboardRuntime();
   }
 
   clear(): void {
@@ -24,12 +25,13 @@ export class OnboardRuntimeBoundary {
   }
 
   getRuntime(): OnboardRuntime {
-    if (!this.runtime) this.runtime = new OnboardRuntime();
+    if (!this.runtime) this.runtime = this.options.createRuntime?.() ?? new OnboardRuntime();
     return this.runtime;
   }
 
   recorders() {
     return {
+      recordOnboardStarted: this.recordOnboardStarted.bind(this),
       startRecordedStep: this.startRecordedStep.bind(this),
       recordStepComplete: this.recordStepComplete.bind(this),
       recordStepSkipped: this.recordStepSkipped.bind(this),
@@ -41,6 +43,10 @@ export class OnboardRuntimeBoundary {
     };
   }
 
+  async recordOnboardStarted(resumed: boolean): Promise<Session> {
+    return this.getRuntime().start({ resumed });
+  }
+
   async startRecordedStep(
     stepName: string,
     updates: {