diff --git a/src/lib/onboard/sandbox-registration.test.ts b/src/lib/onboard/sandbox-registration.test.ts
index 062c132093..b1a341447b 100644
--- a/src/lib/onboard/sandbox-registration.test.ts
+++ b/src/lib/onboard/sandbox-registration.test.ts
@@ -1,14 +1,24 @@
 // SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+import { createHash } from "node:crypto";
 import { createRequire } from "node:module";
 import { afterEach, describe, expect, it, vi } from "vitest";
 
+import { managedStartupE2eProfile } from "../../../scripts/checks/generate-managed-startup-profile-fixture.mts";
 import {
   serializedHostLocalInferenceReceipt,
   serializedLlamaCppHostLocalInferenceReceipt,
 } from "../../../test/helpers/host-local-inference-receipt";
+import type { SandboxWorkloadReceipt } from "../state/registry/types";
 import { createSandboxHostLocalInferenceProvenance } from "../state/registry/host-local-inference";
+import {
+  MANAGED_IMAGE_CAPABILITY_CONTRACT_VERSION,
+  MANAGED_IMAGE_REPOSITORIES,
+  MANAGED_IMAGE_STARTUP_PROFILE_CONTRACT_VERSION,
+  type ManagedImageAgent,
+} from "./managed-image/contract";
+import { encodeManagedStartupProfile } from "./managed-startup/profile";
 
 const requireDist = createRequire(import.meta.url);
 const onboardSession = requireDist("../state/onboard-session.js");
@@ -31,7 +41,103 @@ const runtimeFields = {
   openshellVersion: "0.1.2",
 };
 
+function managedWorkloadReceipt(
+  agent: ManagedImageAgent,
+): Extract<SandboxWorkloadReceipt, { readonly kind: "managed-image" }> {
+  const encodedProfile = encodeManagedStartupProfile(managedStartupE2eProfile(agent));
+  const digest = agent === "openclaw" ? "a" : "b";
+  return {
+    schemaVersion: 1,
+    kind: "managed-image",
+    reference: `${MANAGED_IMAGE_REPOSITORIES[agent]}@sha256:${digest.repeat(64)}`,
+    platform: "linux/amd64",
+    release: "v0.0.100",
+    sourceRevision: "d".repeat(40),
+    sourceCohort: "ghrun-9356-1",
+    capabilityContractVersion: MANAGED_IMAGE_CAPABILITY_CONTRACT_VERSION,
+    startupProfileContractVersion: MANAGED_IMAGE_STARTUP_PROFILE_CONTRACT_VERSION,
+    encodedProfile,
+    startupProfileSha256: createHash("sha256").update(encodedProfile, "utf8").digest("hex"),
+    credentialProxyReplayRequired: false,
+    shared: true,
+  };
+}
+
+function createdRegistryEntryInput(
+  overrides: Partial<Parameters<typeof buildCreatedSandboxRegistryEntry>[0]> = {},
+): Parameters<typeof buildCreatedSandboxRegistryEntry>[0] {
+  return {
+    sandboxName: "demo",
+    inferenceSelection: {
+      model: "llama",
+      provider: "openai-compatible",
+      endpointUrl: null,
+      credentialEnv: null,
+      preferredInferenceApi: null,
+      compatibleEndpointReasoning: null,
+      compatibleEndpointReasoningEffort: null,
+      nimContainer: null,
+    },
+    runtimeFields,
+    agent: null,
+    agentVersionKnown: true,
+    imageTag: null,
+    appliedPolicies: [],
+    plannedMessagingState: undefined,
+    hermesToolGateways: [],
+    hermesDashboardState: { enabled: false, config: null },
+    dashboardPort: 18789,
+    gatewayName: "nemoclaw",
+    gatewayPort: 8080,
+    ...overrides,
+  };
+}
+
 describe("buildCreatedSandboxRegistryEntry", () => {
+  it("records explicit OpenClaw identity for a managed workload receipt (#9356)", () => {
+    const workload = managedWorkloadReceipt("openclaw");
+    const entry = buildCreatedSandboxRegistryEntry(
+      createdRegistryEntryInput({ imageTag: workload.reference, workload }),
+    );
+    const authority = requireDist(
+      "./workload/authority.ts",
+    ) as typeof import("./workload/authority");
+
+    expect(entry.agent).toBe("openclaw");
+    expect(authority.readManagedWorkloadAuthority(entry)?.agent).toBe("openclaw");
+  });
+
+  it("keeps the legacy OpenClaw registry identity for a custom image (#9356)", () => {
+    const entry = buildCreatedSandboxRegistryEntry(
+      createdRegistryEntryInput({
+        agentVersionKnown: false,
+        fromDockerfile: "/tmp/Dockerfile.custom",
+        imageTag: "custom-openclaw:latest",
+        workload: {
+          schemaVersion: 1,
+          kind: "legacy-dockerfile",
+          reference: "custom-openclaw:latest",
+          shared: false,
+        },
+      }),
+    );
+
+    expect(entry.agent).toBeNull();
+  });
+
+  it("rejects a managed receipt for a different agent before registry mutation (#9356)", () => {
+    const workload = managedWorkloadReceipt("hermes");
+    const registerSandbox = vi.fn();
+
+    expect(() =>
+      registerCreatedSandbox({
+        ...createdRegistryEntryInput({ imageTag: workload.reference, workload }),
+        registerSandbox,
+      }),
+    ).toThrow(/agent identity does not match its managed workload receipt/u);
+    expect(registerSandbox).not.toHaveBeenCalled();
+  });
+
   it("copies matching session profile provenance into the durable registry (#8246)", () => {
     const provenance = {
       schemaVersion: 1,
diff --git a/src/lib/onboard/sandbox-registration.ts b/src/lib/onboard/sandbox-registration.ts
index 9c955abb61..2d4128484d 100644
--- a/src/lib/onboard/sandbox-registration.ts
+++ b/src/lib/onboard/sandbox-registration.ts
@@ -26,6 +26,7 @@ import { DEFAULT_TOOL_DISCLOSURE, type ToolDisclosure } from "../tool-disclosure
 import type { DcodeAutoApprovalMode } from "./dcode-auto-approval";
 import { cloneSandboxHostMounts } from "../state/registry/host-mount";
 import { resolveOnboardHermesApiPort } from "./hermes-api-port";
+import { isManagedImageAgent, MANAGED_IMAGE_REPOSITORIES } from "./managed-image/contract";
 import {
   getHermesDashboardRegistryFields,
   type HermesDashboardOnboardState,
@@ -37,7 +38,7 @@ import {
   requireRuntimeProviderBundleForSandbox,
   requireRuntimeProviderMutationAuthority,
 } from "./runtime-provider/access";
-import { getSandboxAgentRegistryFields } from "./sandbox-agent";
+import { getRequestedSandboxAgentName, getSandboxAgentRegistryFields } from "./sandbox-agent";
 
 export type CreatedSandboxRuntimeFields = Pick<
   SandboxEntry,
@@ -224,13 +225,26 @@ export function buildCreatedSandboxRegistryEntry(
       hostLocalInferenceReceipt,
     );
   }
+  const agentFields = getSandboxAgentRegistryFields(input.agent, input.agentVersionKnown);
+  if (workload?.kind === "managed-image") {
+    const requestedAgent = getRequestedSandboxAgentName(input.agent);
+    if (
+      !isManagedImageAgent(requestedAgent) ||
+      !workload.reference.startsWith(`${MANAGED_IMAGE_REPOSITORIES[requestedAgent]}@sha256:`)
+    ) {
+      throw new RuntimeProviderSelectionError(
+        "Sandbox agent identity does not match its managed workload receipt.",
+      );
+    }
+    agentFields.agent = requestedAgent;
+  }
 
   return {
     name: input.sandboxName,
     servingProfileProvenance,
     ...inferenceSelectionRegistryFields(input.inferenceSelection),
     ...input.runtimeFields,
-    ...getSandboxAgentRegistryFields(input.agent, input.agentVersionKnown),
+    ...agentFields,
     imageTag: input.imageTag,
     workload,
     ...(hostLocalInferenceReceipt !== undefined ? { hostLocalInferenceReceipt } : {}),
diff --git a/test/helpers/managed-image-buildless-e2e.ts b/test/helpers/managed-image-buildless-e2e.ts
index 7549771d51..52d4483d4b 100644
--- a/test/helpers/managed-image-buildless-e2e.ts
+++ b/test/helpers/managed-image-buildless-e2e.ts
@@ -729,7 +729,7 @@ function assertManagedLaunch(
       result.payload.registerCalls,
     )}`,
   ).toBeDefined();
-  expect(registration?.agent).toBe(agent === "openclaw" ? null : agent);
+  expect(registration?.agent).toBe(agent);
   if (agent === "langchain-deepagents-code") {
     expect(registration?.dashboardPort).toBe(0);
   }