diff --git a/src/lib/onboard/machine/handlers/provider-inference.test.ts b/src/lib/onboard/machine/handlers/provider-inference.test.ts
index 4c4e0133e5..00e04257f0 100644
--- a/src/lib/onboard/machine/handlers/provider-inference.test.ts
+++ b/src/lib/onboard/machine/handlers/provider-inference.test.ts
@@ -495,6 +495,93 @@ describe("handleProviderInferenceState", () => {
     expect(result).toMatchObject({ provider: "ollama-local", model: "llama3.1" });
   });
 
+  it("reserves the prompted sandbox route when resume skips already-ready inference (#6562)", async () => {
+    const session = createSession({
+      provider: "nvidia-prod",
+      model: "nvidia/nemotron-test",
+      endpointUrl: "https://integrate.api.nvidia.com/v1",
+      credentialEnv: "NVIDIA_INFERENCE_API_KEY",
+      preferredInferenceApi: "openai-responses",
+    });
+    session.steps.provider_selection.status = "complete";
+    const { deps, calls } = createDeps({ isInferenceRouteReady: vi.fn(() => true) });
+    calls.promptName.mockResolvedValueOnce("tm");
+
+    const result = await handleProviderInferenceState({
+      ...baseOptions(deps, session),
+      resume: true,
+      sandboxName: null,
+    });
+
+    expect(calls.promptName).toHaveBeenCalledWith(null);
+    expect(calls.setupNim).not.toHaveBeenCalled();
+    expect(calls.setupInference).not.toHaveBeenCalled();
+    expect(calls.reserveRoute).toHaveBeenCalledWith("tm", {
+      provider: "nvidia-prod",
+      model: "nvidia/nemotron-test",
+      endpointUrl: "https://integrate.api.nvidia.com/v1",
+      credentialEnv: "NVIDIA_INFERENCE_API_KEY",
+      preferredInferenceApi: "openai-responses",
+      gatewayName: "nemoclaw",
+      reservationSessionId: session.sessionId,
+    });
+    expect(result.sandboxName).toBe("tm");
+  });
+
+  it("does not reserve a route when resume skips inference after sandbox completion (#6562)", async () => {
+    const session = createSession({
+      sandboxName: "completed-sandbox",
+      provider: "nvidia-prod",
+      model: "nvidia/nemotron-test",
+      endpointUrl: "https://integrate.api.nvidia.com/v1",
+      credentialEnv: "NVIDIA_INFERENCE_API_KEY",
+      preferredInferenceApi: "openai-responses",
+    });
+    session.steps.provider_selection.status = "complete";
+    session.steps.sandbox.status = "complete";
+    const { deps, calls } = createDeps({ isInferenceRouteReady: vi.fn(() => true) });
+
+    const result = await handleProviderInferenceState({
+      ...baseOptions(deps, session),
+      resume: true,
+      sandboxName: "completed-sandbox",
+    });
+
+    expect(calls.promptName).not.toHaveBeenCalled();
+    expect(calls.setupNim).not.toHaveBeenCalled();
+    expect(calls.setupInference).not.toHaveBeenCalled();
+    expect(calls.reserveRoute).not.toHaveBeenCalled();
+    expect(result.sandboxName).toBe("completed-sandbox");
+  });
+
+  it("reserves the prompted sandbox route after redoing provider selection on resume (#6562)", async () => {
+    const session = createSession();
+    const completedSelection = createSession({ sessionId: "resume-selection-session" });
+    const { deps, calls } = createDeps({ isInferenceRouteReady: vi.fn(() => true) });
+    calls.complete.mockResolvedValueOnce(completedSelection);
+    calls.promptName.mockResolvedValueOnce("tm");
+
+    const result = await handleProviderInferenceState({
+      ...baseOptions(deps, session),
+      resume: true,
+      sandboxName: null,
+    });
+
+    expect(calls.setupNim).toHaveBeenCalledOnce();
+    expect(calls.setupInference).not.toHaveBeenCalled();
+    expect(calls.promptName).toHaveBeenCalledWith(null);
+    expect(calls.reserveRoute).toHaveBeenCalledWith("tm", {
+      provider: "nvidia-prod",
+      model: "nvidia/test",
+      endpointUrl: "https://integrate.api.nvidia.com/v1",
+      credentialEnv: "NVIDIA_INFERENCE_API_KEY",
+      preferredInferenceApi: "openai-responses",
+      gatewayName: "nemoclaw",
+      reservationSessionId: "resume-selection-session",
+    });
+    expect(result.sandboxName).toBe("tm");
+  });
+
   it("coerces a resumed anthropic-messages seed for an OpenAI-only agent (#6294)", async () => {
     const session = createSession({
       provider: "compatible-anthropic-endpoint",
@@ -985,7 +1072,15 @@ describe("handleProviderInferenceState", () => {
     });
 
     expect(calls.reconcileRouter).toHaveBeenCalledOnce();
-    expect(calls.reserveRoute).not.toHaveBeenCalled();
+    expect(calls.reserveRoute).toHaveBeenCalledWith("router-sandbox", {
+      provider: "nvidia-router",
+      model: "router/model",
+      endpointUrl: "http://host.openshell.internal:4000/v1",
+      credentialEnv: null,
+      preferredInferenceApi: null,
+      gatewayName: "nemoclaw",
+      reservationSessionId: session.sessionId,
+    });
   });
 
   // #5974 instance 5: the Model Router Python preflight (`prepareModelRouterVenv`)
diff --git a/src/lib/onboard/machine/handlers/provider-inference.ts b/src/lib/onboard/machine/handlers/provider-inference.ts
index cc78ae9fbd..910f49bf74 100644
--- a/src/lib/onboard/machine/handlers/provider-inference.ts
+++ b/src/lib/onboard/machine/handlers/provider-inference.ts
@@ -636,10 +636,12 @@ export async function handleProviderInferenceState<Gpu, Agent, Host>({
         );
         break;
       }
-      const authoritativeReservationName = authoritativeResumeConfig
-        ? (sandboxName ?? (await deps.promptValidatedSandboxName(agent)))
-        : null;
-      if (authoritativeReservationName) sandboxName = authoritativeReservationName;
+      const sandboxStepComplete = session?.steps?.sandbox?.status === "complete";
+      const resumeReservationName =
+        authoritativeResumeConfig || !sandboxStepComplete
+          ? (sandboxName ?? (await deps.promptValidatedSandboxName(agent)))
+          : null;
+      if (resumeReservationName) sandboxName = resumeReservationName;
       const routedInferenceProvider = deps.isRoutedInferenceProvider(provider);
       if (routedInferenceProvider) {
         // #4564: re-upsert the gateway provider with the sandbox-facing
@@ -667,8 +669,8 @@ export async function handleProviderInferenceState<Gpu, Agent, Host>({
             credentialEnv,
           );
           const reserved =
-            reupserted.ok && authoritativeReservationName
-              ? deps.reserveSandboxInferenceRoute(authoritativeReservationName, {
+            reupserted.ok && resumeReservationName
+              ? deps.reserveSandboxInferenceRoute(resumeReservationName, {
                   provider: selectedProvider,
                   model: selectedModel,
                   endpointUrl: reupserted.endpointUrl,
@@ -688,22 +690,20 @@ export async function handleProviderInferenceState<Gpu, Agent, Host>({
           deps.exitProcess(reupserted.status ?? 1);
         }
         if (reserved === false) {
-          deps.error(
-            `  Failed to reserve inference route for sandbox '${authoritativeReservationName}'.`,
-          );
+          deps.error(`  Failed to reserve inference route for sandbox '${resumeReservationName}'.`);
           deps.exitProcess(1);
         }
         endpointUrl = reupserted.endpointUrl;
       }
-      if (authoritativeReservationName && !routedInferenceProvider) {
+      if (resumeReservationName && !routedInferenceProvider) {
         const reserved = await deps.withGatewayRouteMutationLock(gatewayName, () => {
-          assertProviderInferenceRouteCompatible(deps, gatewayName, authoritativeReservationName, {
+          assertProviderInferenceRouteCompatible(deps, gatewayName, resumeReservationName, {
             provider: selectedProvider,
             model: selectedModel,
             endpointUrl,
             preferredInferenceApi,
           });
-          return deps.reserveSandboxInferenceRoute(authoritativeReservationName, {
+          return deps.reserveSandboxInferenceRoute(resumeReservationName, {
             provider: selectedProvider,
             model: selectedModel,
             endpointUrl,
@@ -714,9 +714,7 @@ export async function handleProviderInferenceState<Gpu, Agent, Host>({
           });
         });
         if (!reserved) {
-          deps.error(
-            `  Failed to reserve inference route for sandbox '${authoritativeReservationName}'.`,
-          );
+          deps.error(`  Failed to reserve inference route for sandbox '${resumeReservationName}'.`);
           deps.exitProcess(1);
         }
       }