diff --git a/lib/canvas/agent-operation-request.ts b/lib/canvas/agent-operation-request.ts
index 7fc8abd10..fc6fa5826 100644
--- a/lib/canvas/agent-operation-request.ts
+++ b/lib/canvas/agent-operation-request.ts
@@ -1,6 +1,13 @@
 import { z } from "zod";
 import type { CanvasOperationPlan } from "@/types/canvas/agent-protocol";
 
+const httpMediaUrlSchema = z
+  .string()
+  .url()
+  .refine((url) => /^https?:\/\//i.test(url), {
+    message: "仅支持 http/https 媒体 URL",
+  });
+
 export const canvasAgentOperationPlanSchema = z
   .object({
     version: z.literal(1),
@@ -89,7 +96,7 @@ export const canvasAgentOperationPlanSchema = z
     media: z
       .object({
         type: z.enum(["image", "video"]),
-        url: z.string().url(),
+        url: httpMediaUrlSchema,
         assetId: z.string().uuid().optional(),
         width: z.number().positive().optional(),
         height: z.number().positive().optional(),
@@ -104,7 +111,7 @@ export const canvasAgentOperationPlanSchema = z
         z.object({
           mediaItemId: z.string().min(1).max(160),
           type: z.enum(["image", "video"]),
-          url: z.string().url(),
+          url: httpMediaUrlSchema,
           assetId: z.string().uuid().optional(),
           width: z.number().positive().optional(),
           height: z.number().positive().optional(),
diff --git a/lib/canvas/agent-operation-route.ts b/lib/canvas/agent-operation-route.ts
index 99edab38f..c2a011c7c 100644
--- a/lib/canvas/agent-operation-route.ts
+++ b/lib/canvas/agent-operation-route.ts
@@ -75,10 +75,14 @@ export async function handleCanvasAgentOperationRouteRequest(params: {
         },
       };
     }
+    const operationPlan: CanvasOperationPlan = {
+      ...body.operationPlan,
+      projectId: planProjectId || params.projectId,
+    };
     const result = await params.applyOperation({
       userId,
       projectId: params.projectId,
-      plan: body.operationPlan,
+      plan: operationPlan,
     });
 
     return {
diff --git a/tests/routes/canvas-agent-operations.test.ts b/tests/routes/canvas-agent-operations.test.ts
index 5d6f23715..128c14fc6 100644
--- a/tests/routes/canvas-agent-operations.test.ts
+++ b/tests/routes/canvas-agent-operations.test.ts
@@ -324,6 +324,30 @@ test.describe("canvas agent operation request schema", () => {
         ],
       })
     ).toContain("operationPlan.mediaItems.0.url");
+
+    expect(
+      issuePathsFor({
+        operation: "insert_beside",
+        anchorNodeId: "image-1",
+        mediaItems: [
+          {
+            ...buildMediaItem(),
+            url: "ftp://example.com/generated.png",
+          },
+        ],
+      })
+    ).toContain("operationPlan.mediaItems.0.url");
+
+    expect(
+      issuePathsFor({
+        operation: "append_revision",
+        sourceNodeIds: ["image-1"],
+        media: {
+          type: "image",
+          url: "file:///tmp/generated.png",
+        },
+      })
+    ).toContain("operationPlan.media.url");
   });
 });
 
@@ -391,6 +415,7 @@ test.describe("canvas agent operation route handler", () => {
     const calls: Array<{
       userId: string;
       projectId: string;
+      planProjectId?: string;
       operationId: string;
     }> = [];
     const expectedResult = buildRouteSuccessResult();
@@ -408,6 +433,7 @@ test.describe("canvas agent operation route handler", () => {
         calls.push({
           userId: input.userId,
           projectId: input.projectId,
+          planProjectId: input.plan.projectId,
           operationId: input.plan.operationId,
         });
         return expectedResult;
@@ -423,11 +449,35 @@ test.describe("canvas agent operation route handler", () => {
       {
         userId: "user-1",
         projectId,
+        planProjectId: projectId,
         operationId: "message-1:canvas-agent:test",
       },
     ]);
   });
 
+  test("fills missing operation plan project id from route project id", async () => {
+    let appliedPlanProjectId = "";
+
+    const response = await handleCanvasAgentOperationRouteRequest({
+      userId: "user-1",
+      projectId,
+      rawBody: buildRouteRequestBody({
+        projectId: undefined,
+        operation: "insert_beside",
+        anchorNodeId: "image-1",
+        mediaItems: [buildMediaItem(1)],
+      }),
+      features: enabledRouteFeatures,
+      applyOperation: async (input) => {
+        appliedPlanProjectId = String(input.plan.projectId || "");
+        return buildRouteSuccessResult();
+      },
+    });
+
+    expect(response.status).toBe(200);
+    expect(appliedPlanProjectId).toBe(projectId);
+  });
+
   test("rejects operation plans for a different project before applying", async () => {
     let operationApplied = false;