feat(server): improve doc tools error handle (#14662)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Centralized sync/status messages for cloud document sync and explicit
user-facing error types.
* Frontend helpers to detect and display tool errors with friendly
names.

* **Bug Fixes**
* Consistent, actionable error reporting for document and attachment
reads instead of silent failures.
* Search and semantic tools now validate workspace sync and permissions
and return clear responses.

* **Tests**
* Added comprehensive tests covering document/blob reads, search tools,
and sync/error paths.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/providers/provider.ts

@@ -470,7 +470,8 @@ export abstract class CopilotProvider<C = any> {
               });
               const searchDocs = buildDocKeywordSearchGetter(
                 ac,
-                indexerService
+                indexerService,
+                models
               );
               tools.doc_keyword_search = createDocKeywordSearchTool(
                 searchDocs.bind(null, options)

packages/backend/server/src/plugins/copilot/tools/blob-read.ts

@@ -18,7 +18,10 @@ export const buildBlobContentGetter = (
     chunk?: number
   ) => {
     if (!options?.user || !options?.workspace || !blobId || !context) {
-      return;
+      return toolError(
+        'Blob Read Failed',
+        'Missing workspace, user, blob id, or copilot context for blob_read.'
+      );
     }
     const canAccess = await ac
       .user(options.user)
@@ -29,7 +32,10 @@ export const buildBlobContentGetter = (
       logger.warn(
         `User ${options.user} does not have access workspace ${options.workspace}`
       );
-      return;
+      return toolError(
+        'Blob Read Failed',
+        'You do not have permission to access this workspace attachment.'
+      );
     }
 
     const contextFile = context.files.find(
@@ -42,7 +48,12 @@ export const buildBlobContentGetter = (
       context.getBlobContent(canonicalBlobId, chunk),
     ]);
     const content = file?.trim() || blob?.trim();
-    if (!content) return;
+    if (!content) {
+      return toolError(
+        'Blob Read Failed',
+        `Attachment ${canonicalBlobId} is not available for reading in the current copilot context.`
+      );
+    }
     const info = contextFile
       ? { fileName: contextFile.name, fileType: contextFile.mimeType }
       : {};
@@ -53,10 +64,7 @@ export const buildBlobContentGetter = (
 };
 
 export const createBlobReadTool = (
-  getBlobContent: (
-    targetId?: string,
-    chunk?: number
-  ) => Promise<object | undefined>
+  getBlobContent: (targetId?: string, chunk?: number) => Promise<object>
 ) => {
   return defineTool({
     description:
@@ -73,13 +81,10 @@ export const createBlobReadTool = (
     execute: async ({ blob_id, chunk }) => {
       try {
         const blob = await getBlobContent(blob_id, chunk);
-        if (!blob) {
-          return;
-        }
         return { ...blob };
       } catch (err: any) {
         logger.error(`Failed to read the blob ${blob_id} in context`, err);
-        return toolError('Blob Read Failed', err.message);
+        return toolError('Blob Read Failed', err.message ?? String(err));
       }
     },
   });

packages/backend/server/src/plugins/copilot/tools/doc-keyword-search.ts

@@ -1,27 +1,43 @@
 import { z } from 'zod';
 
 import type { AccessController } from '../../../core/permission';
+import type { Models } from '../../../models';
 import type { IndexerService, SearchDoc } from '../../indexer';
+import { workspaceSyncRequiredError } from './doc-sync';
 import { toolError } from './error';
 import { defineTool } from './tool';
 import type { CopilotChatOptions } from './types';
 
 export const buildDocKeywordSearchGetter = (
   ac: AccessController,
-  indexerService: IndexerService
+  indexerService: IndexerService,
+  models: Models
 ) => {
   const searchDocs = async (options: CopilotChatOptions, query?: string) => {
-    if (!options || !query?.trim() || !options.user || !options.workspace) {
-      return undefined;
+    const queryTrimmed = query?.trim();
+    if (!options || !queryTrimmed || !options.user || !options.workspace) {
+      return toolError(
+        'Doc Keyword Search Failed',
+        'Missing workspace, user, or query for doc_keyword_search.'
+      );
+    }
+    const workspace = await models.workspace.get(options.workspace);
+    if (!workspace) {
+      return workspaceSyncRequiredError();
     }
     const canAccess = await ac
       .user(options.user)
       .workspace(options.workspace)
       .can('Workspace.Read');
-    if (!canAccess) return undefined;
+    if (!canAccess) {
+      return toolError(
+        'Doc Keyword Search Failed',
+        'You do not have permission to access this workspace.'
+      );
+    }
     const docs = await indexerService.searchDocsByKeyword(
       options.workspace,
-      query
+      queryTrimmed
     );
 
     // filter current user readable docs
@@ -29,13 +45,15 @@ export const buildDocKeywordSearchGetter = (
       .user(options.user)
       .workspace(options.workspace)
       .docs(docs, 'Doc.Read');
-    return readableDocs;
+    return readableDocs ?? [];
   };
   return searchDocs;
 };
 
 export const createDocKeywordSearchTool = (
-  searchDocs: (query: string) => Promise<SearchDoc[] | undefined>
+  searchDocs: (
+    query: string
+  ) => Promise<SearchDoc[] | ReturnType<typeof toolError>>
 ) => {
   return defineTool({
     description:
@@ -50,8 +68,8 @@ export const createDocKeywordSearchTool = (
     execute: async ({ query }) => {
       try {
         const docs = await searchDocs(query);
-        if (!docs) {
-          return;
+        if (!Array.isArray(docs)) {
+          return docs;
         }
         return docs.map(doc => ({
           docId: doc.docId,

packages/backend/server/src/plugins/copilot/tools/doc-read.ts

@@ -3,13 +3,20 @@ import { z } from 'zod';
 
 import { DocReader } from '../../../core/doc';
 import { AccessController } from '../../../core/permission';
-import { Models, publicUserSelect } from '../../../models';
-import { toolError } from './error';
+import { Models } from '../../../models';
+import {
+  documentSyncPendingError,
+  workspaceSyncRequiredError,
+} from './doc-sync';
+import { type ToolError, toolError } from './error';
 import { defineTool } from './tool';
 import type { CopilotChatOptions } from './types';
 
 const logger = new Logger('DocReadTool');
 
+const isToolError = (result: ToolError | object): result is ToolError =>
+  'type' in result && result.type === 'error';
+
 export const buildDocContentGetter = (
   ac: AccessController,
   docReader: DocReader,
@@ -17,8 +24,17 @@ export const buildDocContentGetter = (
 ) => {
   const getDoc = async (options: CopilotChatOptions, docId?: string) => {
     if (!options?.user || !options?.workspace || !docId) {
-      return;
+      return toolError(
+        'Doc Read Failed',
+        'Missing workspace, user, or document id for doc_read.'
+      );
     }
+
+    const workspace = await models.workspace.get(options.workspace);
+    if (!workspace) {
+      return workspaceSyncRequiredError();
+    }
+
     const canAccess = await ac
       .user(options.user)
       .workspace(options.workspace)
@@ -28,23 +44,15 @@ export const buildDocContentGetter = (
       logger.warn(
         `User ${options.user} does not have access to doc ${docId} in workspace ${options.workspace}`
       );
-      return;
+      return toolError(
+        'Doc Read Failed',
+        `You do not have permission to read document ${docId} in this workspace.`
+      );
     }
 
-    const docMeta = await models.doc.getSnapshot(options.workspace, docId, {
-      select: {
-        createdAt: true,
-        updatedAt: true,
-        createdByUser: {
-          select: publicUserSelect,
-        },
-        updatedByUser: {
-          select: publicUserSelect,
-        },
-      },
-    });
+    const docMeta = await models.doc.getAuthors(options.workspace, docId);
     if (!docMeta) {
-      return;
+      return documentSyncPendingError(docId);
     }
 
     const content = await docReader.getDocMarkdown(
@@ -53,7 +61,7 @@ export const buildDocContentGetter = (
       true
     );
     if (!content) {
-      return;
+      return documentSyncPendingError(docId);
     }
 
     return {
@@ -69,8 +77,12 @@ export const buildDocContentGetter = (
   return getDoc;
 };
 
+type DocReadToolResult = Awaited<
+  ReturnType<ReturnType<typeof buildDocContentGetter>>
+>;
+
 export const createDocReadTool = (
-  getDoc: (targetId?: string) => Promise<object | undefined>
+  getDoc: (targetId?: string) => Promise<DocReadToolResult>
 ) => {
   return defineTool({
     description:
@@ -81,13 +93,10 @@ export const createDocReadTool = (
     execute: async ({ doc_id }) => {
       try {
         const doc = await getDoc(doc_id);
-        if (!doc) {
-          return;
-        }
-        return { ...doc };
+        return isToolError(doc) ? doc : { ...doc };
       } catch (err: any) {
         logger.error(`Failed to read the doc ${doc_id}`, err);
-        return toolError('Doc Read Failed', err.message);
+        return toolError('Doc Read Failed', err.message ?? String(err));
       }
     },
   });

packages/backend/server/src/plugins/copilot/tools/doc-semantic-search.ts

@@ -7,6 +7,7 @@ import {
   clearEmbeddingChunk,
   type Models,
 } from '../../../models';
+import { workspaceSyncRequiredError } from './doc-sync';
 import { toolError } from './error';
 import { defineTool } from './tool';
 import type {
@@ -27,14 +28,24 @@ export const buildDocSearchGetter = (
     signal?: AbortSignal
   ) => {
     if (!options || !query?.trim() || !options.user || !options.workspace) {
-      return `Invalid search parameters.`;
+      return toolError(
+        'Doc Semantic Search Failed',
+        'Missing workspace, user, or query for doc_semantic_search.'
+      );
+    }
+    const workspace = await models.workspace.get(options.workspace);
+    if (!workspace) {
+      return workspaceSyncRequiredError();
     }
     const canAccess = await ac
       .user(options.user)
       .workspace(options.workspace)
       .can('Workspace.Read');
     if (!canAccess)
-      return 'You do not have permission to access this workspace.';
+      return toolError(
+        'Doc Semantic Search Failed',
+        'You do not have permission to access this workspace.'
+      );
     const [chunks, contextChunks] = await Promise.all([
       context.matchWorkspaceAll(options.workspace, query, 10, signal),
       docContext?.matchFiles(query, 10, signal) ?? [],
@@ -53,7 +64,7 @@ export const buildDocSearchGetter = (
       fileChunks.push(...contextChunks);
     }
     if (!blobChunks.length && !docChunks.length && !fileChunks.length) {
-      return `No results found for "${query}".`;
+      return [];
     }
 
     const docIds = docChunks.map(c => ({
@@ -101,7 +112,7 @@ export const createDocSemanticSearchTool = (
   searchDocs: (
     query: string,
     signal?: AbortSignal
-  ) => Promise<ChunkSimilarity[] | string | undefined>
+  ) => Promise<ChunkSimilarity[] | ReturnType<typeof toolError>>
 ) => {
   return defineTool({
     description:

packages/backend/server/src/plugins/copilot/tools/doc-sync.ts

@@ -0,0 +1,13 @@
+import { toolError } from './error';
+
+export const LOCAL_WORKSPACE_SYNC_REQUIRED_MESSAGE =
+  'This workspace is local-only and does not have AFFiNE Cloud sync enabled yet. Ask the user to enable workspace sync, then try again.';
+
+export const DOCUMENT_SYNC_PENDING_MESSAGE = (docId: string) =>
+  `Document ${docId} is not available on AFFiNE Cloud yet. Ask the user to wait for workspace sync to finish, then try again.`;
+
+export const workspaceSyncRequiredError = () =>
+  toolError('Workspace Sync Required', LOCAL_WORKSPACE_SYNC_REQUIRED_MESSAGE);
+
+export const documentSyncPendingError = (docId: string) =>
+  toolError('Document Sync Pending', DOCUMENT_SYNC_PENDING_MESSAGE(docId));