diff --git a/libs/langgraph/src/lib/agent.fn.spec.ts b/libs/langgraph/src/lib/agent.fn.spec.ts
index 739ea3026..923ac04ac 100644
--- a/libs/langgraph/src/lib/agent.fn.spec.ts
+++ b/libs/langgraph/src/lib/agent.fn.spec.ts
@@ -76,6 +76,25 @@ describe('agent', () => {
     expect(ref.isLoading()).toBe(true);
   });
 
+  it('submit() resolves after the active stream completes', async () => {
+    const transport = new MockAgentTransport();
+    const ref = withInjectionContext(() =>
+      agent({ apiUrl: '', assistantId: 'a', transport })
+    );
+
+    let settled = false;
+    const submitted = ref.submit({ message: 'hello' }).then(() => {
+      settled = true;
+    });
+
+    await Promise.resolve();
+    expect(settled).toBe(false);
+
+    transport.close();
+    await submitted;
+    expect(settled).toBe(true);
+  });
+
   it('queue() exposes server-side enqueue submissions', async () => {
     const transport = new MockAgentTransport();
     const ref = withInjectionContext(() =>
@@ -135,8 +154,9 @@ describe('agent', () => {
     const ref = withInjectionContext(() =>
       agent({ apiUrl: '', assistantId: 'a', transport })
     );
-    await ref.submit({ message: 'hello' });
+    const submitted = ref.submit({ message: 'hello' });
     transport.close();
+    await submitted;
     await new Promise(r => setTimeout(r, 10));
     ref.reload();
     expect(ref.isLoading()).toBe(true);
@@ -239,6 +259,130 @@ describe('agent', () => {
     ]);
   });
 
+  it('normalizes resume submit input state into a LangGraph command update', async () => {
+    const seen: Array<{ payload: unknown; options: unknown }> = [];
+    const transport = new MockAgentTransport();
+    transport.stream = async function* (
+      _assistantId: string,
+      _threadId: string | null,
+      payload: unknown,
+      _signal: AbortSignal,
+      options?: unknown,
+    ) {
+      seen.push({ payload, options });
+      yield* [];
+    };
+
+    const ref = withInjectionContext(() =>
+      agent({ apiUrl: '', assistantId: 'a', transport, threadId: 'thread-1', throttle: false })
+    );
+
+    await ref.submit({
+      resume: { approved: true },
+      state: { reviewNotes: 'ship it' },
+    });
+
+    expect(seen).toEqual([
+      {
+        payload: null,
+        options: expect.objectContaining({
+          command: {
+            resume: { approved: true },
+            update: { reviewNotes: 'ship it' },
+          },
+        }),
+      },
+    ]);
+  });
+
+  it('normalizes resume submit input messages into a LangGraph command update', async () => {
+    const seen: Array<{ payload: unknown; options: unknown }> = [];
+    const transport = new MockAgentTransport();
+    transport.stream = async function* (
+      _assistantId: string,
+      _threadId: string | null,
+      payload: unknown,
+      _signal: AbortSignal,
+      options?: unknown,
+    ) {
+      seen.push({ payload, options });
+      yield* [];
+    };
+
+    const ref = withInjectionContext(() =>
+      agent({ apiUrl: '', assistantId: 'a', transport, threadId: 'thread-1', throttle: false })
+    );
+
+    await ref.submit({
+      message: 'Approved, continue',
+      resume: { approved: true },
+      state: { reviewer: 'Ada' },
+    });
+
+    expect(seen).toEqual([
+      {
+        payload: null,
+        options: expect.objectContaining({
+          command: {
+            resume: { approved: true },
+            update: {
+              messages: [{ type: 'human', role: 'human', content: 'Approved, continue' }],
+              reviewer: 'Ada',
+            },
+          },
+        }),
+      },
+    ]);
+  });
+
+  it('merges resume submit updates with existing LangGraph command updates', async () => {
+    const seen: Array<{ payload: unknown; options: unknown }> = [];
+    const transport = new MockAgentTransport();
+    transport.stream = async function* (
+      _assistantId: string,
+      _threadId: string | null,
+      payload: unknown,
+      _signal: AbortSignal,
+      options?: unknown,
+    ) {
+      seen.push({ payload, options });
+      yield* [];
+    };
+
+    const ref = withInjectionContext(() =>
+      agent({ apiUrl: '', assistantId: 'a', transport, threadId: 'thread-1', throttle: false })
+    );
+
+    await ref.submit(
+      {
+        resume: { approved: true },
+        state: { reviewer: 'Ada' },
+      },
+      {
+        command: {
+          update: { workflow: 'release' },
+          goto: 'publish',
+        },
+      },
+    );
+
+    expect(seen).toEqual([
+      {
+        payload: null,
+        options: expect.objectContaining({
+          command: {
+            resume: { approved: true },
+            update: {
+              workflow: 'release',
+              reviewer: 'Ada',
+            },
+            goto: 'publish',
+          },
+        }),
+      },
+    ]);
+  });
+
   it('experimentalBranchTree() exposes a branch tree derived from LangGraph history', async () => {
     const root = threadState('root');
     const left = threadState('left', 'root');
diff --git a/libs/langgraph/src/lib/agent.fn.ts b/libs/langgraph/src/lib/agent.fn.ts
index 3cdc83262..1b9770e28 100644
--- a/libs/langgraph/src/lib/agent.fn.ts
+++ b/libs/langgraph/src/lib/agent.fn.ts
@@ -12,7 +12,7 @@ import {
 import { takeUntil } from 'rxjs/operators';
 import type { Observable } from 'rxjs';
 import type { BaseMessage, AIMessage as CoreAIMessage } from '@langchain/core/messages';
-import type { Interrupt, ToolCallWithResult } from '@langchain/langgraph-sdk';
+import type { Command, Interrupt, ToolCallWithResult } from '@langchain/langgraph-sdk';
 import type { BagTemplate, InferBag } from '@langchain/langgraph-sdk';
 import type {
   AgentEvent,
@@ -242,8 +242,7 @@ export function agent<
     history:   historyNeutral,
     submit: (input: AgentSubmitInput | null | undefined, opts?: AgentSubmitOptions & LangGraphSubmitOptions) => {
       const request = buildSubmitRequest(input, opts);
-      manager.submit(request.payload, request.options);
-      return Promise.resolve();
+      return manager.submit(request.payload, request.options);
     },
     stop: () => manager.stop(),
 
@@ -416,18 +415,7 @@ function buildSubmitRequest(
 function buildSubmitPayload(input: AgentSubmitInput | null | undefined): unknown {
   if (input == null) return null;
   if (input.resume !== undefined) return null;
-  if (input.message !== undefined) {
-    const content = typeof input.message === 'string'
-      ? input.message
-      : input.message.map((b: ContentBlock) => (b.type === 'text' ? b.text : JSON.stringify(b))).join('');
-    // `type: 'human'` is what `toMessage()` reads via `_getType` || raw['type'];
-    // `role: 'human'` is what the LangGraph server expects in submit payloads.
-    // Include both so the optimistic local copy projects as a 'user' bubble
-    // (otherwise toMessage falls through to the 'ai' default and renders the
-    // user's question as an assistant message).
-    return { messages: [{ type: 'human', role: 'human', content }], ...(input.state ?? {}) };
-  }
-  return input.state ?? {};
+  return buildSubmitUpdate(input) ?? {};
 }
 
 function normalizeSubmitOptions(
@@ -442,15 +430,45 @@ function normalizeSubmitOptions(
   const next = { ...(opts ?? {}) };
   delete next.resume;
   const command = next.command;
+  const update = buildSubmitUpdate(input);
+  const commandUpdate = mergeCommandUpdate(command?.update, update);
   return {
     ...next,
     command: {
       ...command,
       resume,
+      ...(commandUpdate === undefined ? {} : { update: commandUpdate }),
     },
   };
 }
 
+function buildSubmitUpdate(input: AgentSubmitInput | null | undefined): Record<string, unknown> | undefined {
+  if (input == null) return undefined;
+  if (input.message !== undefined) {
+    const content = typeof input.message === 'string'
+      ? input.message
+      : input.message.map((b: ContentBlock) => (b.type === 'text' ? b.text : JSON.stringify(b))).join('');
+    // `type: 'human'` is what `toMessage()` reads via `_getType` || raw['type'];
+    // `role: 'human'` is what the LangGraph server expects in submit payloads.
+    // Include both so the optimistic local copy projects as a 'user' bubble
+    // (otherwise toMessage falls through to the 'ai' default and renders the
+    // user's question as an assistant message).
+    return { messages: [{ type: 'human', role: 'human', content }], ...(input.state ?? {}) };
+  }
+  return input.state;
+}
+
+function mergeCommandUpdate(
+  existing: Command['update'] | undefined,
+  update: Record<string, unknown> | undefined,
+): Command['update'] | undefined {
+  if (update === undefined) return existing;
+  if (existing == null) return update;
+  if (isRecord(existing)) return { ...existing, ...update };
+  if (Array.isArray(existing)) return [...existing, ...Object.entries(update)];
+  return update;
+}
+
 function randomId(): string {
   return Math.random().toString(36).slice(2);
 }