Fix browser file operations and persist visible save times

Preserve JSON Content-Type when custom idempotency headers are supplied. Expose the latest accepted folder operation timestamp so browser saves remain visible before an agent runs and after all files are deleted.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/work-folders.test.ts

@@ -57,6 +57,18 @@ describe("durable work folders", () => {
     expect(await textContent(f, "memory.md")).toBe("second");
     await expect(svc.write(f, { ...first, body: Buffer.from("different") })).rejects.toMatchObject({ status: 409 });
   });
+  it("retains the last accepted save time after all files are removed", async () => {
+    const f = await folder();
+    expect((await svc.list(f)).lastSavedAt).toBeNull();
+    await svc.write(f, { path: "note", body: Buffer.from("saved"), operationId: "write" });
+    const saved = (await svc.list(f)).lastSavedAt;
+    expect(saved).toEqual(expect.any(String));
+    await svc.remove(f, "note", "delete");
+    const listing = await svc.list(f);
+    expect(listing.files).toEqual([]);
+    expect(Date.parse(listing.lastSavedAt!)).toBeGreaterThanOrEqual(Date.parse(saved!));
+    expect((await svc.list(f, { trash: true })).lastSavedAt).toBe(listing.lastSavedAt);
+  });
   it("retains a deleted copy after the same path is recreated", async () => {
     const f = await folder();
     await svc.write(f, { path: "note", body: Buffer.from("deleted"), operationId: "one" });

server/src/routes/openapi.ts

@@ -5276,7 +5276,7 @@ const workFolderErrors = { 400: r.badRequest, 401: r.unauthorized, 404: r.notFou
 registry.registerPath({ method: "get", path: workFolderPath, tags: ["work-folders"], summary: "List scoped sandbox files or recoverable trash",
   description: "User files require the owning user or an authorized run acting for that user. Company access alone does not grant access.",
   request: { params: workFolderParams, query: z.object({ trash: z.enum(["true", "false"]).optional(), cursor: z.uuid().optional(), limit: z.coerce.number().int().min(1).max(1000).optional() }) },
-  responses: { ...workFolderErrors, 200: r.ok(z.object({ id: z.uuid(), owner: workFolderParams, files: z.array(workFileResponse), nextCursor: z.string().nullable() })) },
+  responses: { ...workFolderErrors, 200: r.ok(z.object({ id: z.uuid(), owner: workFolderParams, files: z.array(workFileResponse), nextCursor: z.string().nullable(), lastSavedAt: z.string().nullable() })) },
 });
 registry.registerPath({ method: "get", path: `${workFolderPath}/content`, tags: ["work-folders"], summary: "Download a scoped file",
   request: { params: workFolderParams, query: z.object({ path: z.string() }) },

server/src/services/work-folders.ts

@@ -5,7 +5,7 @@ import os from "node:os";
 import path from "node:path";
 import { Readable, Transform } from "node:stream";
 import { pipeline } from "node:stream/promises";
-import { and, asc, eq, gt, isNull, isNotNull, sql } from "drizzle-orm";
+import { and, asc, eq, gt, isNull, isNotNull, max, sql } from "drizzle-orm";
 import { workFolders, workFiles, workFileOperations, workFolderObjects, type Db } from "@paperclipai/db";
 import { validateWorkFilePath, type WorkFile, type WorkFolderOwner } from "@paperclipai/shared";
 import { registerWorkFolderObject } from "./work-folder-garbage.js";
@@ -41,7 +41,10 @@ export function workFolderService(db: Db, storage: StorageProvider) {
     const rows = await db.select().from(workFiles).where(and(eq(workFiles.folderId, folder.id),
       eq(workFiles.companyId, folder.companyId), options.trash ? isNotNull(workFiles.deletedAt) : isNull(workFiles.deletedAt),
       options.cursor ? gt(workFiles.id, options.cursor) : undefined)).orderBy(asc(workFiles.id)).limit(limit + 1);
+    const [saved] = await db.select({ at: max(workFileOperations.createdAt) }).from(workFileOperations)
+      .where(and(eq(workFileOperations.companyId, folder.companyId), eq(workFileOperations.folderId, folder.id)));
     return { id: folder.id, owner: { companyId: folder.companyId, scope: folder.scope, ownerId: folder.ownerId },
+      lastSavedAt: saved?.at?.toISOString() ?? null,
       files: rows.slice(0, limit).map(workFileDto), nextCursor: rows.length > limit ? rows[limit - 1]!.id : null };
   }