feat: folder logins for shared hosts, read only plugin sync, full desktop builds

src/backend/database/db/index.ts

@@ -484,6 +484,19 @@ async function initializeCompleteDatabase(): Promise<void> {
     );
     CREATE INDEX IF NOT EXISTS idx_folder_access_owner_folder ON folder_access (owner_user_id, folder);
 
+    CREATE TABLE IF NOT EXISTS shared_folder_auth_overrides (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        user_id TEXT NOT NULL,
+        folder TEXT NOT NULL,
+        protocol TEXT NOT NULL DEFAULT 'ssh',
+        credential_id INTEGER NOT NULL,
+        created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+        updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+        FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE,
+        FOREIGN KEY (credential_id) REFERENCES ssh_credentials (id) ON DELETE CASCADE
+    );
+    CREATE UNIQUE INDEX IF NOT EXISTS shared_folder_auth_overrides_user_folder_protocol_unique ON shared_folder_auth_overrides (user_id, folder, protocol);
+
     CREATE TABLE IF NOT EXISTS plugins (
         id TEXT PRIMARY KEY,
         name TEXT NOT NULL,

src/backend/database/db/schema.mysql.ts

@@ -490,6 +490,38 @@ export const sharedHostAuthOverrides = mysqlTable(
   ],
 );
 
+/**
+ * A recipient's own login for the shared hosts in a folder ("Parent / Child")
+ * and its subfolders. A host's own override still wins.
+ */
+export const sharedFolderAuthOverrides = mysqlTable(
+  "shared_folder_auth_overrides",
+  {
+    id: int("id").autoincrement().primaryKey(),
+    userId: varchar("user_id", { length: 255 })
+      .notNull()
+      .references(() => users.id, { onDelete: "cascade" }),
+    folder: varchar("folder", { length: 255 }).notNull(),
+    protocol: varchar("protocol", { length: 255 }).notNull().default("ssh"),
+    credentialId: int("credential_id")
+      .notNull()
+      .references(() => sshCredentials.id, { onDelete: "cascade" }),
+    createdAt: text("created_at")
+      .notNull()
+      .default(sql`(CURRENT_TIMESTAMP)`),
+    updatedAt: text("updated_at")
+      .notNull()
+      .default(sql`(CURRENT_TIMESTAMP)`),
+  },
+  (table) => [
+    uniqueIndex("shared_folder_auth_overrides_user_folder_protocol_unique").on(
+      table.userId,
+      table.folder,
+      table.protocol,
+    ),
+  ],
+);
+
 export const sharedHostSecrets = mysqlTable(
   "shared_host_secrets",
   {

src/backend/database/db/schema.pg.ts

@@ -490,6 +490,38 @@ export const sharedHostAuthOverrides = pgTable(
   ],
 );
 
+/**
+ * A recipient's own login for the shared hosts in a folder ("Parent / Child")
+ * and its subfolders. A host's own override still wins.
+ */
+export const sharedFolderAuthOverrides = pgTable(
+  "shared_folder_auth_overrides",
+  {
+    id: serial("id").primaryKey(),
+    userId: varchar("user_id", { length: 255 })
+      .notNull()
+      .references(() => users.id, { onDelete: "cascade" }),
+    folder: varchar("folder", { length: 255 }).notNull(),
+    protocol: varchar("protocol", { length: 255 }).notNull().default("ssh"),
+    credentialId: integer("credential_id")
+      .notNull()
+      .references(() => sshCredentials.id, { onDelete: "cascade" }),
+    createdAt: text("created_at")
+      .notNull()
+      .default(sql`CURRENT_TIMESTAMP`),
+    updatedAt: text("updated_at")
+      .notNull()
+      .default(sql`CURRENT_TIMESTAMP`),
+  },
+  (table) => [
+    uniqueIndex("shared_folder_auth_overrides_user_folder_protocol_unique").on(
+      table.userId,
+      table.folder,
+      table.protocol,
+    ),
+  ],
+);
+
 export const sharedHostSecrets = pgTable(
   "shared_host_secrets",
   {

src/backend/database/db/schema.ts

@@ -480,6 +480,38 @@ export const sharedHostAuthOverrides = sqliteTable(
   ],
 );
 
+/**
+ * A recipient's own login for the shared hosts in a folder ("Parent / Child")
+ * and its subfolders. A host's own override still wins.
+ */
+export const sharedFolderAuthOverrides = sqliteTable(
+  "shared_folder_auth_overrides",
+  {
+    id: integer("id").primaryKey({ autoIncrement: true }),
+    userId: text("user_id")
+      .notNull()
+      .references(() => users.id, { onDelete: "cascade" }),
+    folder: text("folder").notNull(),
+    protocol: text("protocol").notNull().default("ssh"),
+    credentialId: integer("credential_id")
+      .notNull()
+      .references(() => sshCredentials.id, { onDelete: "cascade" }),
+    createdAt: text("created_at")
+      .notNull()
+      .default(sql`CURRENT_TIMESTAMP`),
+    updatedAt: text("updated_at")
+      .notNull()
+      .default(sql`CURRENT_TIMESTAMP`),
+  },
+  (table) => [
+    uniqueIndex("shared_folder_auth_overrides_user_folder_protocol_unique").on(
+      table.userId,
+      table.folder,
+      table.protocol,
+    ),
+  ],
+);
+
 export const sharedHostSecrets = sqliteTable(
   "shared_host_secrets",
   {

src/backend/database/repositories/factory.ts

@@ -31,6 +31,7 @@ import { FolderAccessRepository } from "./folder-access-repository.js";
 import { SettingsRepository } from "./settings-repository.js";
 import { HostProtocolAuthRepository } from "./host-protocol-auth-repository.js";
 import { SharedHostAuthOverrideRepository } from "./shared-host-auth-override-repository.js";
+import { SharedFolderAuthOverrideRepository } from "./shared-folder-auth-override-repository.js";
 import { SharedHostSecretsRepository } from "./shared-host-secrets-repository.js";
 import { SshCredentialUsageRepository } from "./ssh-credential-usage-repository.js";
 import { TrustedDeviceRepository } from "./trusted-device-repository.js";
@@ -316,6 +317,15 @@ export function createCurrentSharedHostAuthOverrideRepository(): SharedHostAuthO
   );
 }
 
+export function createCurrentSharedFolderAuthOverrideRepository(): SharedFolderAuthOverrideRepository {
+  return new SharedFolderAuthOverrideRepository(
+    createCurrentRepositoryContext(),
+    createCurrentRepositoryWriteHook(
+      "shared_folder_auth_override_repository_write",
+    ),
+  );
+}
+
 export function createCurrentSshCredentialUsageRepository(): SshCredentialUsageRepository {
   return new SshCredentialUsageRepository(
     createCurrentRepositoryContext(),

src/backend/database/repositories/shared-folder-auth-override-repository.ts

@@ -0,0 +1,115 @@
+import { and, eq, inArray } from "drizzle-orm";
+import type { AuthOverrideProtocol } from "../../../types/auth-protocols.js";
+import { sharedFolderAuthOverrides } from "../db/schema.js";
+import type { DatabaseContext } from "./database-context.js";
+import { deleteReturning, upsert } from "./returning.js";
+
+/** "A / B / C" and the folders above it, closest first. */
+export function folderAndParents(folder: string | null | undefined): string[] {
+  const parts = (folder ?? "")
+    .split(" / ")
+    .map((part) => part.trim())
+    .filter(Boolean);
+  const out: string[] = [];
+  for (let i = parts.length; i > 0; i--) {
+    out.push(parts.slice(0, i).join(" / "));
+  }
+  return out;
+}
+
+export class SharedFolderAuthOverrideRepository {
+  constructor(
+    private readonly context: DatabaseContext,
+    private readonly onWrite?: () => void | Promise<void>,
+  ) {}
+
+  async findCredentialId(
+    userId: string,
+    folder: string,
+    protocol: AuthOverrideProtocol,
+  ): Promise<number | null> {
+    const rows = await this.context.drizzle
+      .select({ credentialId: sharedFolderAuthOverrides.credentialId })
+      .from(sharedFolderAuthOverrides)
+      .where(
+        and(
+          eq(sharedFolderAuthOverrides.userId, userId),
+          eq(sharedFolderAuthOverrides.folder, folder),
+          eq(sharedFolderAuthOverrides.protocol, protocol),
+        ),
+      )
+      .limit(1);
+    return rows[0]?.credentialId ?? null;
+  }
+
+  /**
+   * The login set on the host's folder or the closest folder above it, for
+   * one protocol. Null when none is set.
+   */
+  async findClosest(
+    userId: string,
+    hostFolder: string | null | undefined,
+    protocol: AuthOverrideProtocol,
+  ): Promise<{ folder: string; credentialId: number } | null> {
+    const folders = folderAndParents(hostFolder);
+    if (folders.length === 0) return null;
+    const rows = await this.context.drizzle
+      .select({
+        folder: sharedFolderAuthOverrides.folder,
+        credentialId: sharedFolderAuthOverrides.credentialId,
+      })
+      .from(sharedFolderAuthOverrides)
+      .where(
+        and(
+          eq(sharedFolderAuthOverrides.userId, userId),
+          eq(sharedFolderAuthOverrides.protocol, protocol),
+          inArray(sharedFolderAuthOverrides.folder, folders),
+        ),
+      );
+    for (const folder of folders) {
+      const row = rows.find((candidate) => candidate.folder === folder);
+      if (row) return row;
+    }
+    return null;
+  }
+
+  async setCredential(
+    userId: string,
+    folder: string,
+    protocol: AuthOverrideProtocol,
+    credentialId: number,
+  ): Promise<void> {
+    await upsert(
+      this.context,
+      sharedFolderAuthOverrides,
+      { userId, folder, protocol, credentialId },
+      {
+        target: [
+          sharedFolderAuthOverrides.userId,
+          sharedFolderAuthOverrides.folder,
+          sharedFolderAuthOverrides.protocol,
+        ],
+        set: { credentialId, updatedAt: new Date().toISOString() },
+      },
+    );
+    await this.onWrite?.();
+  }
+
+  async clearCredential(
+    userId: string,
+    folder: string,
+    protocol: AuthOverrideProtocol,
+  ): Promise<boolean> {
+    const rows = await deleteReturning(
+      this.context,
+      sharedFolderAuthOverrides,
+      and(
+        eq(sharedFolderAuthOverrides.userId, userId),
+        eq(sharedFolderAuthOverrides.folder, folder),
+        eq(sharedFolderAuthOverrides.protocol, protocol),
+      ),
+    );
+    if (rows.length > 0) await this.onWrite?.();
+    return rows.length > 0;
+  }
+}

src/backend/database/routes/rbac.ts

@@ -37,8 +37,10 @@ import {
   createCurrentHostResolutionRepository,
   createCurrentRbacAccessRepository,
   createCurrentRoleRepository,
+  createCurrentSharedFolderAuthOverrideRepository,
   createCurrentUserRepository,
 } from "../repositories/factory.js";
+import { findUsableCredential } from "../../hosts/usable-credential.js";
 
 const router = express.Router();
 
@@ -2225,4 +2227,157 @@ router.get(
   },
 );
 
+/** A folder path as hosts store it ("Parent / Child"), or null. */
+function folderParam(value: unknown): string | null {
+  if (typeof value !== "string") return null;
+  const folder = value
+    .split(" / ")
+    .map((part) => part.trim())
+    .filter(Boolean)
+    .join(" / ");
+  return folder && folder.length <= 255 ? folder : null;
+}
+
+/**
+ * @openapi
+ * /rbac/folder-auth/{protocol}:
+ *   get:
+ *     summary: Get the current user's personal login for shared hosts in a folder
+ *     tags: [RBAC]
+ *     parameters:
+ *       - in: path
+ *         name: protocol
+ *         required: true
+ *         schema: { type: string }
+ *       - in: query
+ *         name: folder
+ *         required: true
+ *         schema: { type: string }
+ *     responses:
+ *       200:
+ *         description: The folder, protocol and credential id, or null when none is set.
+ *       400:
+ *         description: Invalid folder or protocol.
+ */
+router.get(
+  "/folder-auth/:protocol",
+  authenticateJWT,
+  requireDataAccess,
+  async (req: express.Request, res: express.Response) => {
+    try {
+      const userId = (req as AuthenticatedRequest).userId!;
+      const protocol = req.params.protocol;
+      const folder = folderParam(req.query.folder);
+      if (!folder) return res.status(400).json({ error: "Invalid folder" });
+      if (!isAuthOverrideProtocol(protocol)) {
+        return res
+          .status(400)
+          .json({ error: "Invalid authentication protocol" });
+      }
+      const credentialId =
+        await createCurrentSharedFolderAuthOverrideRepository().findCredentialId(
+          userId,
+          folder,
+          protocol,
+        );
+      res.json({ folder, protocol, credentialId });
+    } catch (error) {
+      databaseLogger.error("Failed to get folder login", error);
+      res.status(500).json({ error: "Failed to fetch credential" });
+    }
+  },
+);
+
+/**
+ * @openapi
+ * /rbac/folder-auth/{protocol}:
+ *   put:
+ *     summary: Set the current user's personal login for shared hosts in a folder
+ *     description: >
+ *       Used for every host shared with the user in this folder and its
+ *       subfolders that has no personal login of its own. credentialId null
+ *       clears it.
+ *     tags: [RBAC]
+ *     parameters:
+ *       - in: path
+ *         name: protocol
+ *         required: true
+ *         schema: { type: string }
+ *     requestBody:
+ *       required: true
+ *       content:
+ *         application/json:
+ *           schema:
+ *             type: object
+ *             required: [folder, credentialId]
+ *             properties:
+ *               folder: { type: string }
+ *               credentialId: { type: integer, nullable: true }
+ *     responses:
+ *       200:
+ *         description: Saved.
+ *       400:
+ *         description: Invalid folder, protocol or credential id.
+ *       404:
+ *         description: The credential is not one the user can use.
+ */
+router.put(
+  "/folder-auth/:protocol",
+  authenticateJWT,
+  requireDataAccess,
+  async (req: express.Request, res: express.Response) => {
+    try {
+      const userId = (req as AuthenticatedRequest).userId!;
+      const protocol = req.params.protocol;
+      const folder = folderParam(req.body?.folder);
+      const credentialId = req.body?.credentialId ?? null;
+      if (!folder) return res.status(400).json({ error: "Invalid folder" });
+      if (!isAuthOverrideProtocol(protocol)) {
+        return res
+          .status(400)
+          .json({ error: "Invalid authentication protocol" });
+      }
+      if (
+        credentialId !== null &&
+        (!Number.isInteger(credentialId) || credentialId <= 0)
+      ) {
+        return res.status(400).json({
+          error: "credentialId must be a positive integer or null",
+        });
+      }
+
+      const repository = createCurrentSharedFolderAuthOverrideRepository();
+      if (credentialId === null) {
+        await repository.clearCredential(userId, folder, protocol);
+      } else {
+        if (!(await findUsableCredential(credentialId, userId))) {
+          return res.status(404).json({ error: "Credential not found" });
+        }
+        await repository.setCredential(userId, folder, protocol, credentialId);
+      }
+
+      const { ipAddress, userAgent } = getRequestMeta(req);
+      await logAudit({
+        userId,
+        username: await getAuditUsername(userId),
+        action:
+          credentialId === null
+            ? "clear_shared_folder_auth_override"
+            : "set_shared_folder_auth_override",
+        resourceType: "folder",
+        resourceName: folder,
+        details: JSON.stringify({ protocol, credentialId }),
+        ipAddress,
+        userAgent,
+        success: true,
+      }).catch(() => undefined);
+
+      res.json({ success: true, folder, protocol, credentialId });
+    } catch (error) {
+      databaseLogger.error("Failed to set folder login", error);
+      res.status(500).json({ error: "Failed to update credential" });
+    }
+  },
+);
+
 export default router;

src/backend/hosts/resolve-host-credentials.ts

@@ -87,11 +87,18 @@ export async function resolveHostCredentials(
             ...recipientHost,
             authOverrides: {
               ...authOverrides,
-              ssh: {
-                credentialId: resolution.credentialId,
-                required: false,
-                ownerAuthShared: !!host.shareSshAuth,
-              },
+              ssh: resolution.folder
+                ? {
+                    required: false,
+                    ownerAuthShared: !!host.shareSshAuth,
+                    folder: resolution.folder,
+                    folderCredentialId: resolution.credentialId,
+                  }
+                : {
+                    credentialId: resolution.credentialId,
+                    required: false,
+                    ownerAuthShared: !!host.shareSshAuth,
+                  },
             },
             authType:
               credential.key || credential.privateKey

src/backend/plugins/sync-registry.ts

@@ -16,7 +16,7 @@ import type {
   SyncRow,
 } from "@termix-ssh/plugin-sdk/backend";
 
-/** Core-only extras a plugin registration cannot set. */
+/** Extras core sets for its own entities. A plugin may set the first four. */
 export interface CoreSyncEntityOptions {
   /** Server-to-desktop only. A desktop never pushes it. */
   readOnly?: boolean;
@@ -58,6 +58,54 @@ export interface RegisteredSyncEntity
   encryptedFields: readonly string[];
 }
 
+/** What a plugin registration may carry. Anything else is dropped. */
+const PLUGIN_KEYS = [
+  "type",
+  "table",
+  "userColumn",
+  "encryptedFields",
+  "references",
+  "order",
+  "readOnlyFields",
+  "singleton",
+  "answersTo",
+  "shouldSync",
+  "permissions",
+  "serialize",
+  "deserialize",
+  "afterWrite",
+  "remove",
+  "readOnly",
+  "load",
+  "write",
+  "erase",
+] as const;
+
+function pluginEntity(entity: SyncEntityRegistration): SyncEntityRegistration {
+  const picked: Record<string, unknown> = {};
+  for (const key of PLUGIN_KEYS) {
+    if (entity[key] !== undefined) picked[key] = entity[key];
+  }
+  const out = picked as unknown as SyncEntityRegistration;
+  if (out.load || out.write || out.erase) {
+    if (!out.load || !out.write || !out.erase) {
+      throw new Error(
+        `Sync entity "${entity.type}" needs load, write and erase together`,
+      );
+    }
+    // A plugin only ever syncs its own rows both ways; rows it builds for
+    // a user come down as read only copies.
+    if (out.readOnly !== true) {
+      throw new Error(
+        `Sync entity "${entity.type}" with load must be readOnly`,
+      );
+    }
+  } else if (!out.table) {
+    throw new Error(`Sync entity "${entity.type}" needs a table or load`);
+  }
+  return out;
+}
+
 const entities = new Map<string, RegisteredSyncEntity>();
 const listeners = new Set<() => void>();
 
@@ -81,7 +129,7 @@ export function registerEntity(
   }
 
   const registered: RegisteredSyncEntity = {
-    ...entity,
+    ...(owner === CORE_OWNER ? entity : pluginEntity(entity)),
     ...(owner === CORE_OWNER ? core : {}),
     owner,
     order: entity.order ?? 100,

src/backend/tests/database/repositories/shared-folder-auth-override-repository.test.ts

@@ -0,0 +1,98 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { sql } from "drizzle-orm";
+import {
+  folderAndParents,
+  SharedFolderAuthOverrideRepository,
+} from "../../../database/repositories/shared-folder-auth-override-repository.js";
+import { TestSqliteDatabase } from "./test-support.js";
+
+describe("folderAndParents", () => {
+  it("lists the folder, then each folder above it", () => {
+    expect(folderAndParents("Prod / Web / EU")).toEqual([
+      "Prod / Web / EU",
+      "Prod / Web",
+      "Prod",
+    ]);
+    expect(folderAndParents(" Prod ")).toEqual(["Prod"]);
+    expect(folderAndParents("")).toEqual([]);
+    expect(folderAndParents(null)).toEqual([]);
+  });
+});
+
+describe("SharedFolderAuthOverrideRepository", () => {
+  let adapter: TestSqliteDatabase | null = null;
+
+  afterEach(async () => {
+    await adapter?.close();
+    adapter = null;
+  });
+
+  async function createRepository(onWrite?: () => void) {
+    adapter = new TestSqliteDatabase();
+    const context = await adapter.connect();
+    await adapter.exec(`
+      INSERT INTO users (id, username, password_hash)
+      VALUES ('recipient', 'recipient', 'hash'), ('other', 'other', 'hash');
+      INSERT INTO ssh_credentials (id, user_id, name, auth_type)
+      VALUES (7, 'recipient', 'cred-seven', 'password'),
+        (8, 'recipient', 'cred-eight', 'password');
+    `);
+    return new SharedFolderAuthOverrideRepository(context, onWrite);
+  }
+
+  it("sets, updates and clears a login per user, folder and protocol", async () => {
+    let writes = 0;
+    const repository = await createRepository(() => {
+      writes += 1;
+    });
+
+    await repository.setCredential("recipient", "Prod", "ssh", 7);
+    await repository.setCredential("recipient", "Prod", "ssh", 8);
+    await repository.setCredential("recipient", "Prod", "rdp", 7);
+    await expect(
+      repository.findCredentialId("recipient", "Prod", "ssh"),
+    ).resolves.toBe(8);
+    await expect(
+      repository.findCredentialId("other", "Prod", "ssh"),
+    ).resolves.toBeNull();
+
+    await expect(
+      repository.clearCredential("recipient", "Prod", "ssh"),
+    ).resolves.toBe(true);
+    await expect(
+      repository.clearCredential("recipient", "Prod", "ssh"),
+    ).resolves.toBe(false);
+    expect(writes).toBe(4);
+  });
+
+  it("finds the login of the closest folder above a host", async () => {
+    const repository = await createRepository();
+    await repository.setCredential("recipient", "Prod", "ssh", 7);
+    await repository.setCredential("recipient", "Prod / Web", "ssh", 8);
+
+    await expect(
+      repository.findClosest("recipient", "Prod / Web / EU", "ssh"),
+    ).resolves.toEqual({ folder: "Prod / Web", credentialId: 8 });
+    await expect(
+      repository.findClosest("recipient", "Prod / DB", "ssh"),
+    ).resolves.toEqual({ folder: "Prod", credentialId: 7 });
+    await expect(
+      repository.findClosest("recipient", "Staging", "ssh"),
+    ).resolves.toBeNull();
+    await expect(
+      repository.findClosest("recipient", "Prod", "rdp"),
+    ).resolves.toBeNull();
+    await expect(
+      repository.findClosest("recipient", null, "ssh"),
+    ).resolves.toBeNull();
+  });
+
+  it("drops the login when its credential is deleted", async () => {
+    const repository = await createRepository();
+    await repository.setCredential("recipient", "Prod", "ssh", 7);
+    await adapter!.run(sql`DELETE FROM ssh_credentials WHERE id = 7`);
+    await expect(
+      repository.findCredentialId("recipient", "Prod", "ssh"),
+    ).resolves.toBeNull();
+  });
+});

src/backend/tests/database/routes/rbac-host-auth-override.test.ts

@@ -11,6 +11,11 @@ const state = vi.hoisted(() => ({
   credentialUsable: true,
   credentialId: 7 as number | null,
   writes: [] as Array<{ protocol: string; credentialId: number | null }>,
+  folderWrites: [] as Array<{
+    folder: string;
+    protocol: string;
+    credentialId: number | null;
+  }>,
   auditCalls: [] as Array<Record<string, unknown>>,
 }));
 
@@ -97,6 +102,25 @@ vi.mock("../../../database/repositories/factory.js", () => ({
       return true;
     },
   }),
+  createCurrentSharedFolderAuthOverrideRepository: () => ({
+    findCredentialId: async () => 7,
+    setCredential: async (
+      _userId: string,
+      folder: string,
+      protocol: string,
+      credentialId: number,
+    ) => {
+      state.folderWrites.push({ folder, protocol, credentialId });
+    },
+    clearCredential: async (
+      _userId: string,
+      folder: string,
+      protocol: string,
+    ) => {
+      state.folderWrites.push({ folder, protocol, credentialId: null });
+      return true;
+    },
+  }),
   createCurrentUserRepository: () => ({
     findById: async () => ({ id: "recipient", username: "recipient" }),
   }),
@@ -109,6 +133,7 @@ vi.mock("../../../database/repositories/factory.js", () => ({
 
 vi.mock("../../../utils/audit-logger.js", () => ({
   getRequestMeta: () => ({ ipAddress: "", userAgent: "" }),
+  getAuditUsername: async (userId: string) => userId,
   logAudit: vi.fn(async (entry: Record<string, unknown>) => {
     state.auditCalls.push(entry);
   }),
@@ -134,6 +159,8 @@ describe("shared host authentication override routes", () => {
     method: "get" | "put",
     body: Record<string, unknown> = {},
     protocol = "ssh",
+    path = "/host-access/:hostId/auth/:protocol",
+    query: Record<string, unknown> = {},
   ): Promise<{ status: number; body: unknown }> {
     const routeLayer = (
       router as unknown as {
@@ -152,15 +179,14 @@ describe("shared host authentication override routes", () => {
         }>;
       }
     ).stack.find(
-      (layer) =>
-        layer.route?.path === "/host-access/:hostId/auth/:protocol" &&
-        layer.route.methods[method],
+      (layer) => layer.route?.path === path && layer.route.methods[method],
     );
     if (!routeLayer?.route) throw new Error(`Missing ${method} route`);
 
     const handlers = routeLayer.route.stack.map((layer) => layer.handle);
     const req = {
       params: { hostId: "42", protocol },
+      query,
       body,
       headers: {},
       ip: "127.0.0.1",
@@ -210,9 +236,103 @@ describe("shared host authentication override routes", () => {
     state.credentialUsable = true;
     state.credentialId = 7;
     state.writes = [];
+    state.folderWrites = [];
     state.auditCalls = [];
   });
 
+  describe("folder logins", () => {
+    const FOLDER = "/folder-auth/:protocol";
+
+    it("reads the login for a folder", async () => {
+      const response = await invoke("get", {}, "ssh", FOLDER, {
+        folder: " Prod /  Web ",
+      });
+      expect(response).toEqual({
+        status: 200,
+        body: { folder: "Prod / Web", protocol: "ssh", credentialId: 7 },
+      });
+    });
+
+    it("sets and clears the login and audits both", async () => {
+      expect(
+        (
+          await invoke(
+            "put",
+            { folder: "Prod", credentialId: 8 },
+            "ssh",
+            FOLDER,
+          )
+        ).status,
+      ).toBe(200);
+      expect(
+        (
+          await invoke(
+            "put",
+            { folder: "Prod", credentialId: null },
+            "ssh",
+            FOLDER,
+          )
+        ).status,
+      ).toBe(200);
+      expect(state.folderWrites).toEqual([
+        { folder: "Prod", protocol: "ssh", credentialId: 8 },
+        { folder: "Prod", protocol: "ssh", credentialId: null },
+      ]);
+      expect(state.auditCalls.map((call) => call.action)).toEqual([
+        "set_shared_folder_auth_override",
+        "clear_shared_folder_auth_override",
+      ]);
+    });
+
+    it("rejects a bad folder, protocol or credential", async () => {
+      expect(
+        (await invoke("get", {}, "ssh", FOLDER, { folder: "" })).status,
+      ).toBe(400);
+      expect(
+        (
+          await invoke(
+            "put",
+            { folder: "x".repeat(300), credentialId: 8 },
+            "ssh",
+            FOLDER,
+          )
+        ).status,
+      ).toBe(400);
+      expect(
+        (
+          await invoke(
+            "put",
+            { folder: "Prod", credentialId: 8 },
+            "smtp",
+            FOLDER,
+          )
+        ).status,
+      ).toBe(400);
+      expect(
+        (
+          await invoke(
+            "put",
+            { folder: "Prod", credentialId: -1 },
+            "ssh",
+            FOLDER,
+          )
+        ).status,
+      ).toBe(400);
+      state.credentialUsable = false;
+      expect(
+        (
+          await invoke(
+            "put",
+            { folder: "Prod", credentialId: 99 },
+            "ssh",
+            FOLDER,
+          )
+        ).status,
+      ).toBe(404);
+      expect(state.folderWrites).toEqual([]);
+    });
+  });
+
   it("returns the current override for a role-derived shared recipient", async () => {
     const response = await invoke("get");
     expect(response).toEqual({

src/backend/tests/plugins/sync-registry.test.ts

@@ -117,6 +117,56 @@ describe("entity aliases", () => {
     expect(getEntity("thing")?.readOnly).toBeUndefined();
     expect(getEntity("thing")?.load).toBeUndefined();
   });
+
+  it("lets a plugin sync rows it builds as read only copies", () => {
+    const load = async () => [];
+    registerEntity("demo", {
+      type: "sharedIcons",
+      table: null,
+      readOnly: true,
+      load,
+      write: async () => undefined,
+      erase: async () => undefined,
+    });
+    expect(getEntity("sharedIcons")).toMatchObject({ readOnly: true, load });
+  });
+
+  it("refuses a plugin entity that loads rows but can be pushed", () => {
+    expect(() =>
+      registerEntity("demo", {
+        type: "pushable",
+        table: null,
+        load: async () => [],
+        write: async () => undefined,
+        erase: async () => undefined,
+      }),
+    ).toThrow(/readOnly/);
+    expect(() =>
+      registerEntity("demo", {
+        type: "halfDone",
+        table: null,
+        readOnly: true,
+        load: async () => [],
+      }),
+    ).toThrow(/load, write and erase/);
+    expect(() =>
+      registerEntity("demo", { type: "nothing", table: null }),
+    ).toThrow(/table or load/);
+  });
+
+  it("drops core only keys a plugin puts on its registration", () => {
+    registerEntity("demo", {
+      type: "sneaky",
+      table: {},
+      covers: () => true,
+      canReference: async () => true,
+      hashIgnore: ["x"],
+    } as never);
+    const entity = getEntity("sneaky")!;
+    expect(entity.covers).toBeUndefined();
+    expect(entity.canReference).toBeUndefined();
+    expect(entity.hashIgnore).toBeUndefined();
+  });
 });
 
 describe("core sync entities", () => {

src/backend/tests/utils/shared-host-auth-resolver-folder.test.ts

@@ -0,0 +1,125 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const state = vi.hoisted(() => ({
+  hostOverride: null as number | null,
+  folderOverride: null as { folder: string; credentialId: number } | null,
+  ownerSecret: null as Record<string, unknown> | null,
+  usable: new Set<number>(),
+  folderLookups: [] as Array<{ folder: unknown; protocol: string }>,
+}));
+
+vi.mock("../../hosts/protocol-auth/registry.js", () => ({
+  isAuthOverrideProtocol: (protocol: string) => protocol === "ssh",
+}));
+
+vi.mock("../../hosts/usable-credential.js", () => ({
+  findUsableCredential: async (id: number) =>
+    state.usable.has(id) ? { id, username: `user-${id}` } : null,
+}));
+
+vi.mock("../../database/repositories/factory.js", () => ({
+  createCurrentHostResolutionRepository: () => ({
+    findHostOwnerId: async () => "owner",
+  }),
+  createCurrentRbacAccessRepository: () => ({
+    findActiveHostAccess: async () => null,
+  }),
+  createCurrentRoleRepository: () => ({ listUserRoleIds: async () => [] }),
+  createCurrentSharedHostAuthOverrideRepository: () => ({
+    findCredentialId: async () => state.hostOverride,
+  }),
+  createCurrentSharedFolderAuthOverrideRepository: () => ({
+    findClosest: async (_userId: string, folder: unknown, protocol: string) => {
+      state.folderLookups.push({ folder, protocol });
+      return state.folderOverride;
+    },
+  }),
+}));
+
+vi.mock("../../utils/shared-host-secrets-manager.js", () => ({
+  SharedHostSecretsManager: {
+    getInstance: () => ({
+      getSecretForUser: async () => state.ownerSecret,
+      snapshotForUser: async () => undefined,
+    }),
+  },
+}));
+
+const { resolveRecipientSharedHostAuthentication } =
+  await import("../../utils/shared-host-auth-resolver.js");
+
+const host = (extra: Record<string, unknown> = {}) =>
+  ({
+    id: 42,
+    userId: "owner",
+    folder: "Prod / Web",
+    authType: "credential",
+    credentialId: 99,
+    shareSshAuth: false,
+    ...extra,
+  }) as never;
+
+beforeEach(() => {
+  state.hostOverride = null;
+  state.folderOverride = null;
+  state.ownerSecret = null;
+  state.usable = new Set();
+  state.folderLookups = [];
+});
+
+describe("folder logins for shared hosts", () => {
+  it("uses the folder's login when the host has none of its own", async () => {
+    state.folderOverride = { folder: "Prod", credentialId: 7 };
+    state.usable.add(7);
+    const result = await resolveRecipientSharedHostAuthentication(
+      host(),
+      42,
+      "recipient",
+      "ssh",
+    );
+    expect(result).toMatchObject({
+      source: "personal-override",
+      credentialId: 7,
+      folder: "Prod",
+    });
+    expect(state.folderLookups).toEqual([
+      { folder: "Prod / Web", protocol: "ssh" },
+    ]);
+  });
+
+  it("lets the host's own login win over the folder's", async () => {
+    state.hostOverride = 5;
+    state.folderOverride = { folder: "Prod", credentialId: 7 };
+    state.usable.add(5).add(7);
+    const result = await resolveRecipientSharedHostAuthentication(
+      host(),
+      42,
+      "recipient",
+      "ssh",
+    );
+    expect(result).toMatchObject({ credentialId: 5 });
+    expect(result).not.toHaveProperty("folder");
+  });
+
+  it("skips a folder login the user can no longer use", async () => {
+    state.folderOverride = { folder: "Prod", credentialId: 7 };
+    state.ownerSecret = { authType: "password", password: "x" };
+    const result = await resolveRecipientSharedHostAuthentication(
+      host({ shareSshAuth: true }),
+      42,
+      "recipient",
+      "ssh",
+    );
+    expect(result).toMatchObject({ source: "owner-shared" });
+  });
+
+  it("asks for a login when nothing is set", async () => {
+    const result = await resolveRecipientSharedHostAuthentication(
+      host(),
+      42,
+      "recipient",
+      "ssh",
+    );
+    expect(result).toEqual({ source: "required" });
+  });
+});

src/backend/utils/shared-host-auth-resolver.ts

@@ -4,6 +4,7 @@ import {
   createCurrentHostResolutionRepository,
   createCurrentRbacAccessRepository,
   createCurrentRoleRepository,
+  createCurrentSharedFolderAuthOverrideRepository,
   createCurrentSharedHostAuthOverrideRepository,
 } from "../database/repositories/factory.js";
 import type {
@@ -23,6 +24,8 @@ export type RecipientSharedHostAuthResolution =
       source: "personal-override";
       credentialId: number;
       credential: HostResolutionCredentialRecord;
+      /** Set when the login comes from the folder, not the host itself. */
+      folder?: string;
     }
   | {
       source: "owner-shared";
@@ -54,8 +57,8 @@ function isOwnerAuthShared(
 
 /**
  * Applies the shared-host authentication precedence independently from any
- * transport: recipient override, shared owner auth, secretless auth, then
- * "required".
+ * transport: recipient override on the host, then on its folder, shared
+ * owner auth, secretless auth, then "required".
  */
 export async function resolveRecipientSharedHostAuthentication(
   host: HostResolutionHostRecord,
@@ -91,6 +94,31 @@ export async function resolveRecipientSharedHostAuthentication(
     }
   }
 
+  try {
+    const folderOverride =
+      await createCurrentSharedFolderAuthOverrideRepository().findClosest(
+        userId,
+        host.folder,
+        protocol,
+      );
+    if (folderOverride) {
+      const credential = await findUsableCredential(
+        folderOverride.credentialId,
+        userId,
+      );
+      if (credential) {
+        return {
+          source: "personal-override",
+          credentialId: folderOverride.credentialId,
+          credential,
+          folder: folderOverride.folder,
+        };
+      }
+    }
+  } catch {
+    // Same as a host override: an unreadable one counts as none.
+  }
+
   if (isOwnerAuthShared(host, protocol)) {
     if (protocol === "ssh" && host.authType === "agent") {
       return {

src/ui/api/rbac-api.ts

@@ -388,6 +388,54 @@ export async function getHostAuthOverride(
   }
 }
 
+/**
+ * The user's own login for hosts shared with them in a folder. On a desktop
+ * linked to a server, pass a shared host from the folder so the call goes to
+ * that server.
+ */
+export async function getFolderAuthOverride(
+  folder: string,
+  protocol: AuthOverrideProtocol,
+  sharedCopySyncId?: string | null,
+): Promise<{
+  folder: string;
+  protocol: AuthOverrideProtocol;
+  credentialId: number | null;
+}> {
+  try {
+    const target = await getSharedCopyTarget(0, sharedCopySyncId);
+    const response = await target.api.get(`/rbac/folder-auth/${protocol}`, {
+      params: { folder },
+    });
+    return response.data;
+  } catch (error) {
+    throw handleApiError(error, "fetch folder authentication override");
+  }
+}
+
+export async function setFolderAuthOverride(
+  folder: string,
+  protocol: AuthOverrideProtocol,
+  credentialId: number | null,
+  sharedCopySyncId?: string | null,
+): Promise<{
+  success: boolean;
+  folder: string;
+  protocol: AuthOverrideProtocol;
+  credentialId: number | null;
+}> {
+  try {
+    const target = await getSharedCopyTarget(0, sharedCopySyncId);
+    const response = await target.api.put(`/rbac/folder-auth/${protocol}`, {
+      folder,
+      credentialId,
+    });
+    return response.data;
+  } catch (error) {
+    throw handleApiError(error, "update folder authentication override");
+  }
+}
+
 export async function setHostAuthOverride(
   hostId: number,
   protocol: AuthOverrideProtocol,

src/ui/main-axios.ts

@@ -1317,6 +1317,8 @@ export {
   revokeHostAccess,
   getHostAuthOverride,
   setHostAuthOverride,
+  getFolderAuthOverride,
+  setFolderAuthOverride,
   getPermissionsCatalog,
   getSharedHosts,
 } from "@/api/rbac-api";

src/ui/plugin-host/sdk-ui.ts

@@ -640,6 +640,7 @@ export {
   getExternalAutoProvision,
   getHostAccess,
   getHostAuthOverride,
+  getFolderAuthOverride,
   getHostPassword,
   getHostPolicy,
   type HostPolicy,
@@ -682,6 +683,7 @@ export {
   saveCredentialSidebarPreferences,
   saveHostSidebarPreferences,
   setHostAuthOverride,
+  setFolderAuthOverride,
   shareFolder,
   shareHost,
   type SSHHostWithStatus,