diff --git a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts
index 7f63af339..08c12bb1c 100644
--- a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts
+++ b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts
@@ -320,7 +320,10 @@ describe('Idempotency-Key', () => {
       resolveModel3dRequestKey({
         attemptNonce: null,
         endpoint: 'text-to-model',
-        body: { generation: { model: 'v3.1-20260211' } },
+        body: {
+          generation: { model: 'v3.1-20260211', prompt: '木椅' },
+          target: { kind: 'projectResource', projectId: 'project-1' },
+        },
       }),
     ).toMatch(/^[\x21-\x7e]{1,128}$/);
   });
@@ -329,12 +332,18 @@ describe('Idempotency-Key', () => {
     const left = resolveModel3dRequestKey({
       attemptNonce: 'model3d-fixed',
       endpoint: 'text-to-model',
-      body: { generation: { texture: true, model: 'v3.1-20260211' } },
+      body: {
+        generation: { texture: true, model: 'v3.1-20260211', prompt: '木椅' },
+        target: { kind: 'projectResource', projectId: 'project-1' },
+      },
     });
     const right = resolveModel3dRequestKey({
       attemptNonce: 'model3d-fixed',
       endpoint: 'text-to-model',
-      body: { generation: { model: 'v3.1-20260211', texture: true } },
+      body: {
+        generation: { model: 'v3.1-20260211', texture: true, prompt: '木椅' },
+        target: { kind: 'projectResource', projectId: 'project-1' },
+      },
     });
     expect(right).toBe(left);
   });
diff --git a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts
index e2ee10ed7..f5d894301 100644
--- a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts
+++ b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts
@@ -1,5 +1,10 @@
 import type { ExternalGenerationJobStatusRecord } from '../../../../packages/shared/src/contracts/externalGeneration';
-import type { Model3dGenerationSource } from '../../../../packages/shared/src/contracts/model3d';
+import type {
+  Model3dGenerationSource,
+  Model3dGenerationTarget,
+  Model3dImageToModelRequest,
+  Model3dTextToModelRequest,
+} from '../../../../packages/shared/src/contracts/model3d';
 import { isAbortError, isTimeoutError } from '../../../services/apiClient';
 import type {
   EditorCanvasGenerationCompletionInput,
@@ -41,7 +46,8 @@ export type Model3dSubmissionPlan = {
   attemptNonce: string;
   requestKey: string;
   title: string;
-  body: Record<string, unknown>;
+  /** 提交体就是端点契约本身：形状错误在编译期暴露，而不是等服务端拒绝。 */
+  body: Model3dTextToModelRequest | Model3dImageToModelRequest;
 };
 
 export function resolveModel3dResultTitle(dialog: GenerateDialogState): string {
@@ -106,43 +112,28 @@ export function buildModel3dSubmissionPlan({
     return { ok: false, message: paramsResult.reason };
   }
   const params = paramsResult.params;
-  const prompt = dialog.prompt.trim();
-  const source =
-    dialog.mode === 'model3d-image-to-model'
-      ? resolveModel3dImageSource(dialog)
-      : null;
-  if (dialog.mode === 'model3d-text-to-model' && !prompt) {
-    return { ok: false, message: MODEL3D_TEXT_PROMPT_REQUIRED_MESSAGE };
-  }
-  if (dialog.mode === 'model3d-image-to-model' && !source) {
-    return { ok: false, message: MODEL3D_IMAGE_SOURCE_REQUIRED_MESSAGE };
-  }
   const endpoint = resolveModel3dEndpoint(dialog.mode);
   const attemptNonce = resolveModel3dAttemptNonce(dialog.model3dAttemptNonce);
-  const body: Record<string, unknown> = {
-    ...(source ? { source } : {}),
-    // 价格相关参数永远全量给出：provider 的隐式默认值会直接改变价格，
-    // 唯一例外是 texture=false 档位不带 textureQuality（后端显式拒绝这个组合）。
-    generation: {
-      model: DEFAULT_MODEL3D_MODEL_VERSION,
-      ...(dialog.mode === 'model3d-text-to-model' ? { prompt } : {}),
-      texture: params.texture,
-      pbr: params.pbr,
-      ...(params.textureQuality
-        ? { textureQuality: params.textureQuality }
-        : {}),
-      geometryQuality: params.geometryQuality,
-      quad: params.quad,
-      smartLowPoly: params.smartLowPoly,
-      generateParts: params.generateParts,
-    },
-    target: {
-      kind: 'projectResource',
-      projectId: trimmedProjectId,
-      ...(canvasCompletion ? { canvasCompletion } : {}),
-    },
+  // 价格相关参数永远全量给出：provider 的隐式默认值会直接改变价格，
+  // 唯一例外是 texture=false 档位不带 textureQuality（后端显式拒绝这个组合）。
+  const generation = {
+    model: DEFAULT_MODEL3D_MODEL_VERSION,
+    texture: params.texture,
+    pbr: params.pbr,
+    ...(params.textureQuality ? { textureQuality: params.textureQuality } : {}),
+    geometryQuality: params.geometryQuality,
+    quad: params.quad,
+    smartLowPoly: params.smartLowPoly,
+    generateParts: params.generateParts,
   };
-  return {
+  const target: Model3dGenerationTarget = {
+    kind: 'projectResource',
+    projectId: trimmedProjectId,
+    ...(canvasCompletion ? { canvasCompletion } : {}),
+  };
+  const finish = (
+    body: Model3dTextToModelRequest | Model3dImageToModelRequest,
+  ): { ok: true; plan: Model3dSubmissionPlan } => ({
     ok: true,
     plan: {
       endpoint,
@@ -155,7 +146,21 @@ export function buildModel3dSubmissionPlan({
       title: resolveModel3dResultTitle(dialog),
       body,
     },
-  };
+  });
+
+  if (dialog.mode === 'model3d-image-to-model') {
+    const source = resolveModel3dImageSource(dialog);
+    if (!source) {
+      return { ok: false, message: MODEL3D_IMAGE_SOURCE_REQUIRED_MESSAGE };
+    }
+    return finish({ source, generation, target });
+  }
+
+  const prompt = dialog.prompt.trim();
+  if (!prompt) {
+    return { ok: false, message: MODEL3D_TEXT_PROMPT_REQUIRED_MESSAGE };
+  }
+  return finish({ generation: { ...generation, prompt }, target });
 }
 
 /**
@@ -174,7 +179,7 @@ export function resolveModel3dRequestKey({
 }: {
   attemptNonce?: string | null;
   endpoint: Model3dPricingEndpoint;
-  body: Record<string, unknown>;
+  body: Model3dTextToModelRequest | Model3dImageToModelRequest;
 }): string {
   const nonce = resolveModel3dAttemptNonce(attemptNonce);
   return `${nonce}-${fingerprintModel3dRequest(endpoint, body)}`;
diff --git a/src/services/image-editor/editorProjectClient.ts b/src/services/image-editor/editorProjectClient.ts
index 9f463d45c..2e04bd5f6 100644
--- a/src/services/image-editor/editorProjectClient.ts
+++ b/src/services/image-editor/editorProjectClient.ts
@@ -10,6 +10,10 @@ import {
 } from '../../../packages/shared/src/contracts/editorAudio';
 import type { EditorSceneGenerationRequest } from '../../../packages/shared/src/contracts/editorScene';
 import type { ExternalGenerationJobStatusRecord } from '../../../packages/shared/src/contracts/externalGeneration';
+import type {
+  Model3dImageToModelRequest,
+  Model3dTextToModelRequest,
+} from '../../../packages/shared/src/contracts/model3d';
 import { requestJson } from '../apiClient';
 import { EDITOR_GENERATION_REQUEST_RETRY_OPTIONS } from './editorRetryOptions';
 
@@ -1742,7 +1746,8 @@ export async function submitModel3dGenerationRequest({
   idempotencyKey,
 }: {
   endpoint: Model3dPricingEndpoint;
-  body: Record<string, unknown>;
+  // 提交体直接用端点契约：形状不符（缺 target、generation 结构错）在编译期就会暴露。
+  body: Model3dTextToModelRequest | Model3dImageToModelRequest;
   idempotencyKey: string;
 }) {
   return requestJson<Model3dGenerationSubmissionResponse>(