diff --git a/src/lib/onboard/machine/core-flow-phases.ts b/src/lib/onboard/machine/core-flow-phases.ts
index 91011a26a8d..af4a72b7734 100644
--- a/src/lib/onboard/machine/core-flow-phases.ts
+++ b/src/lib/onboard/machine/core-flow-phases.ts
@@ -2,7 +2,12 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { WebSearchConfig } from "../../inference/web-search";
-import { assertProviderSelectedContext, type OnboardFlowContext } from "./flow-context";
+import {
+  assertProviderSelectedContext,
+  mergeProviderModelSelectedContext,
+  mergeSandboxCreatedContext,
+  type OnboardFlowContext,
+} from "./flow-context";
 import { runCoreOnboardFlowSequence } from "./flow-slices";
 import {
   handleProviderInferenceState,
@@ -75,8 +80,7 @@ export function createCoreOnboardFlowPhases<
       });
 
       return {
-        context: {
-          ...context,
+        context: mergeProviderModelSelectedContext(context, {
           session: providerInferenceResult.session,
           sandboxName: providerInferenceResult.sandboxName,
           model: providerInferenceResult.model,
@@ -88,7 +92,7 @@ export function createCoreOnboardFlowPhases<
           preferredInferenceApi: providerInferenceResult.preferredInferenceApi,
           nimContainer: providerInferenceResult.nimContainer,
           webSearchConfig: providerInferenceResult.webSearchConfig,
-        },
+        }),
         result: providerInferenceResult.stateResults,
       };
     },
@@ -121,14 +125,13 @@ export function createCoreOnboardFlowPhases<
       });
 
       return {
-        context: {
-          ...context,
+        context: mergeSandboxCreatedContext(context, {
           session: sandboxStateResult.session,
           sandboxName: sandboxStateResult.sandboxName,
-          webSearchConfig: sandboxStateResult.webSearchConfig ?? null,
+          webSearchConfig: sandboxStateResult.webSearchConfig,
           selectedMessagingChannels: sandboxStateResult.selectedMessagingChannels,
           webSearchSupported: sandboxStateResult.webSearchSupported,
-        },
+        }),
         result: sandboxStateResult.stateResult,
       };
     },
diff --git a/src/lib/onboard/machine/flow-context.test.ts b/src/lib/onboard/machine/flow-context.test.ts
index dbd7eafcdd0..8ddd580d298 100644
--- a/src/lib/onboard/machine/flow-context.test.ts
+++ b/src/lib/onboard/machine/flow-context.test.ts
@@ -8,6 +8,8 @@ import {
   assertProviderSelectedContext,
   assertSandboxCreatedContext,
   mergeOnboardFlowContext,
+  mergeProviderModelSelectedContext,
+  mergeSandboxCreatedContext,
   type OnboardFlowContext,
   onboardFlowPhaseResult,
 } from "./flow-context";
@@ -64,6 +66,29 @@ describe("onboard flow context helpers", () => {
     expect(result.result).toMatchObject({ next: "gateway", transitionKind: "advance" });
   });
 
+  it("merges provider/model-selected context updates", () => {
+    const context = mergeProviderModelSelectedContext(baseContext(), {
+      session: createSession(),
+      sandboxName: "my-assistant",
+      provider: "nvidia-prod",
+      model: "model",
+      endpointUrl: "https://example.test/v1",
+      credentialEnv: "NVIDIA_INFERENCE_API_KEY",
+      hermesAuthMethod: null,
+      hermesToolGateways: [],
+      preferredInferenceApi: "openai-responses",
+      nimContainer: null,
+      webSearchConfig: null,
+    });
+
+    expect(context).toMatchObject({
+      sandboxName: "my-assistant",
+      provider: "nvidia-prod",
+      model: "model",
+      credentialEnv: "NVIDIA_INFERENCE_API_KEY",
+    });
+  });
+
   it("asserts provider-selected context before sandbox setup", () => {
     const context = mergeOnboardFlowContext(baseContext(), {
       provider: "nvidia-prod",
@@ -79,6 +104,35 @@ describe("onboard flow context helpers", () => {
     );
   });
 
+  it("merges sandbox-created context updates", () => {
+    const providerContext = mergeProviderModelSelectedContext(baseContext(), {
+      session: createSession(),
+      sandboxName: null,
+      provider: "nvidia-prod",
+      model: "model",
+      endpointUrl: null,
+      credentialEnv: null,
+      hermesAuthMethod: null,
+      hermesToolGateways: [],
+      preferredInferenceApi: null,
+      nimContainer: null,
+      webSearchConfig: null,
+    });
+    const context = mergeSandboxCreatedContext(providerContext, {
+      session: createSession(),
+      sandboxName: "my-assistant",
+      webSearchConfig: null,
+      selectedMessagingChannels: ["telegram"],
+      webSearchSupported: true,
+    });
+
+    expect(context).toMatchObject({
+      sandboxName: "my-assistant",
+      selectedMessagingChannels: ["telegram"],
+      webSearchSupported: true,
+    });
+  });
+
   it("asserts sandbox-created context before final phases", () => {
     const context = mergeOnboardFlowContext(baseContext(), {
       sandboxName: "my-assistant",
diff --git a/src/lib/onboard/machine/flow-context.ts b/src/lib/onboard/machine/flow-context.ts
index 761e71681bb..bb7ace415ab 100644
--- a/src/lib/onboard/machine/flow-context.ts
+++ b/src/lib/onboard/machine/flow-context.ts
@@ -30,11 +30,16 @@ export interface OnboardFlowContext<Agent = unknown, Gpu = unknown, SandboxGpuCo
   gpuPassthrough: boolean;
 }
 
-export type ProviderSelectedOnboardFlowContext<Context extends OnboardFlowContext> = Context & {
-  model: string;
-  provider: string;
-  sandboxGpuConfig: NonNullable<Context["sandboxGpuConfig"]>;
-};
+export type ProviderModelSelectedOnboardFlowContext<Context extends OnboardFlowContext> =
+  Context & {
+    model: string;
+    provider: string;
+  };
+
+export type ProviderSelectedOnboardFlowContext<Context extends OnboardFlowContext> =
+  ProviderModelSelectedOnboardFlowContext<Context> & {
+    sandboxGpuConfig: NonNullable<Context["sandboxGpuConfig"]>;
+  };
 
 export type SandboxCreatedOnboardFlowContext<Context extends OnboardFlowContext> = Context & {
   sandboxName: string;
@@ -50,6 +55,28 @@ export interface OnboardFlowPhaseResult<Context extends OnboardFlowContext = Onb
   result: OnboardStateHandlerResult;
 }
 
+export interface ProviderModelSelectedContextUpdate {
+  session: Session | null;
+  sandboxName: string | null;
+  model: string;
+  provider: string;
+  endpointUrl: string | null;
+  credentialEnv: string | null;
+  hermesAuthMethod: string | null;
+  hermesToolGateways: string[];
+  preferredInferenceApi: string | null;
+  nimContainer: string | null;
+  webSearchConfig: WebSearchConfig | null;
+}
+
+export interface SandboxCreatedContextUpdate {
+  session: Session | null;
+  sandboxName: string;
+  webSearchConfig: WebSearchConfig | null;
+  selectedMessagingChannels: string[];
+  webSearchSupported: boolean;
+}
+
 export function assertProviderSelectedContext<Context extends OnboardFlowContext>(
   context: Context,
   stepName: string,
@@ -75,6 +102,20 @@ export function mergeOnboardFlowContext<Context extends OnboardFlowContext>(
   return { ...context, ...patch };
 }
 
+export function mergeProviderModelSelectedContext<Context extends OnboardFlowContext>(
+  context: Context,
+  patch: ProviderModelSelectedContextUpdate,
+): ProviderModelSelectedOnboardFlowContext<Context> {
+  return { ...context, ...patch };
+}
+
+export function mergeSandboxCreatedContext<Context extends OnboardFlowContext>(
+  context: ProviderModelSelectedOnboardFlowContext<Context>,
+  patch: SandboxCreatedContextUpdate,
+): SandboxCreatedOnboardFlowContext<Context> {
+  return { ...context, ...patch };
+}
+
 export function onboardFlowPhaseResult<Context extends OnboardFlowContext>(
   context: Context,
   result: OnboardStateHandlerResult,