diff --git a/frontend/src/documents/SelectionFloatingActions.tsx b/frontend/src/documents/SelectionFloatingActions.tsx
index d42d0c3..5707980 100644
--- a/frontend/src/documents/SelectionFloatingActions.tsx
+++ b/frontend/src/documents/SelectionFloatingActions.tsx
@@ -250,8 +250,34 @@ const SelectionFloatingActions: React.FC<SelectionFloatingActionsProps> = ({
     const fetchPromise = (async () => {
       try {
         const data = await getFolderTree();
-        setRemoteFolderTree(data);
-        return data;
+
+        // Convert flat list to tree
+        const nodeMap = new Map<string, FolderTreeNode>();
+        data.forEach((item) => {
+          nodeMap.set(item.id, {
+            ...item,
+            children: [],
+          } as FolderTreeNode);
+        });
+
+        const roots: FolderTreeNode[] = [];
+        data.forEach((item) => {
+          const node = nodeMap.get(item.id);
+          if (!node) return;
+
+          if (item.children && item.children.length > 0) {
+            node.children = item.children
+              .map((id) => nodeMap.get(id))
+              .filter((n): n is FolderTreeNode => Boolean(n));
+          }
+
+          if (!item.parent_id) {
+            roots.push(node);
+          }
+        });
+
+        setRemoteFolderTree(roots);
+        return roots;
       } catch (error) {
         console.warn('[selection] Failed to load folder tree', error);
         setRemoteFolderTree([]);
diff --git a/frontend/src/hooks/documents/useCorrespondents.ts b/frontend/src/hooks/documents/useCorrespondents.ts
index 12435b1..c7fd447 100644
--- a/frontend/src/hooks/documents/useCorrespondents.ts
+++ b/frontend/src/hooks/documents/useCorrespondents.ts
@@ -1,15 +1,9 @@
 import { MutableRefObject, useCallback, useState } from 'react';
 import type { Correspondent } from '../../types/documents';
 
-type ApiClient = {
-  get: (path: string) => Promise<{ data: unknown }>;
-  post: (path: string, body: unknown) => Promise<{ data: unknown }>;
-  patch: (path: string, body: unknown) => Promise<{ data: unknown }>;
-  delete: (path: string) => Promise<{ data: unknown }>;
-};
+import { listCorrespondents, createCorrespondent, updateCorrespondent, deleteCorrespondent } from '../../lib/apiClient';
 
 interface UseCorrespondentsOptions {
-  apiClient: ApiClient;
   notifyApiError: (error: unknown, fallback: string) => void;
   setStatusMessage: (message: string, variant?: string) => void;
   tenantIdRef: MutableRefObject<string | null>;
@@ -17,7 +11,6 @@ interface UseCorrespondentsOptions {
 }
 
 const useCorrespondents = ({
-  apiClient,
   notifyApiError,
   setStatusMessage,
   tenantIdRef,
@@ -28,7 +21,7 @@ const useCorrespondents = ({
   const refreshCorrespondents = useCallback(async () => {
     const requestTenantId = tenantIdRef.current;
     try {
-      const { data } = await apiClient.get('/correspondents');
+      const data = await listCorrespondents();
       if (tenantIdRef.current !== requestTenantId) {
         return;
       }
@@ -39,7 +32,7 @@ const useCorrespondents = ({
       }
       notifyApiError(error, 'Unable to load correspondents.');
     }
-  }, [apiClient, notifyApiError, tenantIdRef]);
+  }, [notifyApiError, tenantIdRef]);
 
   const handleCorrespondentUpdate = useCallback(
     async (correspondentId: string, changes: { name?: string }) => {
@@ -61,7 +54,7 @@ const useCorrespondents = ({
       }
 
       try {
-        await apiClient.patch(`/correspondents/${correspondentId}`, payload);
+        await updateCorrespondent(correspondentId, payload);
         await refreshCorrespondents();
         setStatusMessage('Correspondent updated.', 'success');
         return true;
@@ -71,7 +64,7 @@ const useCorrespondents = ({
         throw new Error(message);
       }
     },
-    [apiClient, notifyApiError, refreshCorrespondents, setStatusMessage],
+    [notifyApiError, refreshCorrespondents, setStatusMessage],
   );
 
   const handleCorrespondentCreate = useCallback(
@@ -81,7 +74,7 @@ const useCorrespondents = ({
         throw new Error('Correspondent name is required.');
       }
       try {
-        const { data } = await apiClient.post('/correspondents', { name: trimmed });
+        const data = await createCorrespondent({ name: trimmed });
         await refreshCorrespondents();
         setStatusMessage('Correspondent created.', 'success');
         return data;
@@ -91,7 +84,7 @@ const useCorrespondents = ({
         throw new Error(message);
       }
     },
-    [apiClient, notifyApiError, refreshCorrespondents, setStatusMessage],
+    [notifyApiError, refreshCorrespondents, setStatusMessage],
   );
 
   const handleCorrespondentDelete = useCallback(
@@ -112,7 +105,7 @@ const useCorrespondents = ({
       };
 
       try {
-        await apiClient.delete(`/correspondents/${correspondentId}`);
+        await deleteCorrespondent(correspondentId);
         await refreshCorrespondents();
 
         mapDocumentCaches?.(stripFromDoc);
@@ -125,7 +118,7 @@ const useCorrespondents = ({
         throw new Error(message);
       }
     },
-    [apiClient, mapDocumentCaches, notifyApiError, refreshCorrespondents, setStatusMessage],
+    [mapDocumentCaches, notifyApiError, refreshCorrespondents, setStatusMessage],
   );
 
   return {
diff --git a/frontend/src/hooks/documents/useDocumentCorrespondentActions.ts b/frontend/src/hooks/documents/useDocumentCorrespondentActions.ts
index 726476f..76d3a06 100644
--- a/frontend/src/hooks/documents/useDocumentCorrespondentActions.ts
+++ b/frontend/src/hooks/documents/useDocumentCorrespondentActions.ts
@@ -2,10 +2,7 @@ import { useCallback, useMemo } from 'react';
 import type { Identifier } from '../../types/identifiers';
 
 
-type ApiClient = {
-  post: (path: string, body?: unknown) => Promise<{ data: unknown }>;
-  delete: (path: string) => Promise<{ data: unknown }>;
-};
+import { addDocumentCorrespondent, removeDocumentCorrespondent } from '../../lib/apiClient';
 
 interface CorrespondentOption {
   id?: string;
@@ -14,7 +11,6 @@ interface CorrespondentOption {
 }
 
 interface UseDocumentCorrespondentActionsArgs {
-  apiClient: ApiClient;
   correspondents: CorrespondentOption[];
   handleCorrespondentCreate: (payload: { name: string }) => Promise<CorrespondentOption | null>;
   notifyApiError: (error: unknown, fallback: string) => void;
@@ -26,7 +22,6 @@ interface UseDocumentCorrespondentActionsArgs {
 }
 
 const useDocumentCorrespondentActions = ({
-  apiClient,
   correspondents,
   handleCorrespondentCreate,
   notifyApiError,
@@ -56,10 +51,7 @@ const useDocumentCorrespondentActions = ({
         throw new Error('Missing document or correspondent.');
       }
       try {
-        await apiClient.post(`/documents/${documentId}/correspondents`, {
-          assignments: [{ correspondent_id: correspondentId }],
-          replace: false,
-        });
+        await addDocumentCorrespondent(documentId, correspondentId);
         if (updateDocumentCaches) {
           const resolved = correspondent
             || correspondents.find((entry) => entry?.id === correspondentId)
@@ -88,7 +80,7 @@ const useDocumentCorrespondentActions = ({
         throw new Error(message);
       }
     },
-    [apiClient, correspondents, notifyApiError, setStatusMessage, updateDocumentCaches],
+    [correspondents, notifyApiError, setStatusMessage, updateDocumentCaches],
   );
 
   const handleCorrespondentRemove = useCallback(
@@ -100,7 +92,7 @@ const useDocumentCorrespondentActions = ({
         throw new Error('Missing document or correspondent.');
       }
       try {
-        await apiClient.delete(`/documents/${documentId}/correspondents/${correspondentId}`);
+        await removeDocumentCorrespondent(documentId, correspondentId);
         if (updateDocumentCaches) {
           updateDocumentCaches(documentId, (doc) => {
             if (!doc || !Array.isArray(doc.correspondents)) {
@@ -120,7 +112,7 @@ const useDocumentCorrespondentActions = ({
         throw new Error(message);
       }
     },
-    [apiClient, notifyApiError, setStatusMessage, updateDocumentCaches],
+    [notifyApiError, setStatusMessage, updateDocumentCaches],
   );
 
   const normalizeOption = (
diff --git a/frontend/src/hooks/documents/useDocumentTagging.ts b/frontend/src/hooks/documents/useDocumentTagging.ts
index 7dedd6f..fb64b65 100644
--- a/frontend/src/hooks/documents/useDocumentTagging.ts
+++ b/frontend/src/hooks/documents/useDocumentTagging.ts
@@ -8,16 +8,13 @@ interface TagRecord {
   [key: string]: unknown;
 }
 
-interface ApiClient {
-  post: <T = { data: unknown }>(path: string, payload: unknown) => Promise<{ data: T } | T>;
-}
+import { createTag, bulkTagDocuments, bulkReanalyzeDocuments } from '../../lib/apiClient';
 
 interface TagManager {
   buildPayload: (input: { label: string }) => Record<string, unknown>;
 }
 
 interface UseDocumentTaggingArgs {
-  apiClient: ApiClient;
   tags: TagRecord[];
   tagManager: TagManager;
   refreshTags: () => Promise<void> | void;
@@ -42,7 +39,6 @@ interface BulkTagOperationResult {
 }
 
 const useDocumentTagging = ({
-  apiClient,
   tags,
   tagManager,
   refreshTags,
@@ -85,9 +81,9 @@ const useDocumentTagging = ({
           for (const label of normalized) {
             let tag = tags.find((item) => item.label.toLowerCase() === label.toLowerCase()) || null;
             if (!tag) {
-              const payload = tagManager.buildPayload({ label });
-              const response = await apiClient.post<{ id?: Identifier; label: string }>('/tags', payload);
-              tag = 'data' in response ? response.data : response;
+              const payload = tagManager.buildPayload({ label }) as { label: string; color?: string | null };
+              const response = await createTag(payload);
+              tag = response as TagRecord;
               await refreshTags();
             }
             createdIds.push(tag.id);
@@ -137,7 +133,7 @@ const useDocumentTagging = ({
           return { ok: false, reason: 'no-tags' };
         }
 
-        await apiClient.post('/documents/bulk/tags', {
+        await bulkTagDocuments({
           document_ids: targetDocumentIds,
           tag_ids: tagIds,
           action,
@@ -180,7 +176,6 @@ const useDocumentTagging = ({
       refreshTags,
       notifyApiError,
       tagManager,
-      apiClient,
       updateDocumentCaches,
     ],
   );
@@ -259,14 +254,11 @@ const useDocumentTagging = ({
       }
 
       try {
-        const response = await apiClient.post<{ queued?: number }>(
-          '/documents/bulk/reanalyze',
-          {
-            document_ids: targetIds,
-            force: true,
-          },
-        );
-        const payload = 'data' in response ? response.data : response;
+        const response = await bulkReanalyzeDocuments({
+          document_ids: targetIds,
+          force: true,
+        });
+        const payload = response;
         const queued = payload?.queued != null
           ? Number(payload.queued)
           : targetIds.length;
@@ -280,7 +272,7 @@ const useDocumentTagging = ({
         notifyApiError(error, message);
       }
     },
-    [resolveTargetDocumentIds, notifyApiError, setStatusMessage, apiClient],
+    [resolveTargetDocumentIds, notifyApiError, setStatusMessage],
   );
 
   return {
diff --git a/frontend/src/hooks/documents/useDocumentUploads.ts b/frontend/src/hooks/documents/useDocumentUploads.ts
index f239c74..617db5a 100644
--- a/frontend/src/hooks/documents/useDocumentUploads.ts
+++ b/frontend/src/hooks/documents/useDocumentUploads.ts
@@ -2,7 +2,7 @@ import { useCallback, useRef, useState } from 'react';
 import type { Dispatch, MutableRefObject, SetStateAction } from 'react';
 import useFileDrop from './useFileDrop';
 import { DEFAULT_FOLDER_NAME, hasFiles } from '../../app/workspaceUtils';
-import { fetchDocument } from '../../lib/apiClient';
+import { fetchDocument, uploadDocument, resolveFolderPath } from '../../lib/apiClient';
 import type { Identifier } from '../../types/identifiers';
 
 type FolderId = Identifier | 'root' | null;
@@ -26,17 +26,6 @@ type UploadQueueItem = {
   conflictDocumentId: Identifier | null;
 };
 
-interface UploadResponse {
-  reused?: boolean;
-  document?: unknown;
-  folder?: { id?: FolderId };
-}
-
-interface ApiClient {
-  post<T = UploadResponse>(url: string, payload: unknown): Promise<{ data: T; status?: number }>;
-  get<T = { document?: unknown }>(url: string): Promise<{ data: T }>;
-}
-
 type StatusLevel = 'success' | 'info' | 'warning' | 'error' | string;
 type NotifyApiError = (error: unknown, fallbackMessage?: string) => void;
 type SetStatusMessage = (message: string, level?: StatusLevel) => void;
@@ -59,7 +48,7 @@ interface FileSystemDirectoryReaderLike {
   ) => void;
 }
 
-interface FileSystemFileEntryLike {
+interface FileSystemFileEntryLike extends FileSystemEntry {
   isFile: true;
   isDirectory: false;
   name: string;
@@ -69,12 +58,19 @@ interface FileSystemFileEntryLike {
   ) => void;
 }
 
-interface FileSystemDirectoryEntryLike {
+interface FileSystemDirectoryEntryLike extends FileSystemEntry {
   isFile: false;
   isDirectory: true;
   name: string;
   createReader: () => FileSystemDirectoryReaderLike;
 }
+const isFileEntry = (entry: FileSystemEntryLike): entry is FileSystemFileEntryLike => {
+  return entry.isFile && !entry.isDirectory;
+};
+
+const isDirectoryEntry = (entry: FileSystemEntryLike): entry is FileSystemDirectoryEntryLike => {
+  return entry.isDirectory && !entry.isFile && 'createReader' in entry;
+};
 
 const mapFilesToEntries = (filesInput?: FileList | File[] | null): FileEntry[] => {
   if (!filesInput) {
@@ -96,7 +92,6 @@ const mapFilesToEntries = (filesInput?: FileList | File[] | null): FileEntry[] =
 };
 
 interface UseDocumentUploadsArgs {
-  apiClient: ApiClient;
   token?: string | null;
   selectedFolder?: FolderId;
   currentFolderName?: string | null;
@@ -126,7 +121,6 @@ interface UseDocumentUploadsResult {
 }
 
 const useDocumentUploads = ({
-  apiClient,
   token,
   selectedFolder,
   currentFolderName,
@@ -158,11 +152,10 @@ const useDocumentUploads = ({
       }
 
       try {
-        const { data, status } = await apiClient.post('/documents', formData);
-        const duplicate = data?.reused || status === 200;
-        const document = data?.document ?? data ?? null;
+        const { reused, document, status } = await uploadDocument(formData);
+        const duplicate = reused || status === 200;
         return {
-          document,
+          document: document ?? null,
           duplicate,
           statusCode: status ?? (duplicate ? 200 : 201),
           conflictDocumentId: null,
@@ -192,7 +185,7 @@ const useDocumentUploads = ({
         throw wrapped;
       }
     },
-    [apiClient, notifyApiError, setStatusMessage],
+    [notifyApiError, setStatusMessage],
   );
 
   const appendQueueItems = useCallback((entries: FileEntry[], targetFolderId?: FolderId) => {
@@ -244,15 +237,12 @@ const useDocumentUploads = ({
         segments: trimmedSegments,
       };
 
-      const { data } = await apiClient.post<{ folder?: { id?: FolderId | null } }>(
-        '/folders/path',
-        payload,
-      );
-      const resolvedId = (data?.folder?.id ?? null) as FolderId;
+      const { folder } = await resolveFolderPath(payload);
+      const resolvedId = (folder?.id ?? null) as FolderId;
       cache.set(cacheKey, resolvedId);
       return resolvedId;
     },
-    [apiClient],
+    [],
   );
 
   const extractFilesFromDataTransfer = useCallback(async (dataTransfer: DataTransfer) => {
@@ -294,10 +284,10 @@ const useDocumentUploads = ({
 
     const walkEntry = async (entry: FileSystemEntryLike | null, ancestors: string[] = []) => {
       if (!entry) return;
-      if (entry.isFile) {
+      if (isFileEntry(entry)) {
         const file = await new Promise<File>((resolve, reject) => {
           try {
-            (entry as unknown as FileSystemFileEntryLike).file(resolve, reject);
+            entry.file(resolve, reject);
           } catch (error) {
             console.warn('[Uploads] entry.file failed', error);
             reject(error as Error);
@@ -306,9 +296,9 @@ const useDocumentUploads = ({
         pushFile(file, ancestors);
         return;
       }
-      if (entry.isDirectory) {
+      if (isDirectoryEntry(entry)) {
         const nextAncestors = entry.name ? [...ancestors, entry.name] : [...ancestors];
-        const reader = (entry as unknown as FileSystemDirectoryEntryLike).createReader();
+        const reader = entry.createReader();
         const entries = await readAllEntries(reader);
         for (const child of entries) {
           await walkEntry(child, nextAncestors);
diff --git a/frontend/src/hooks/documents/useDocumentsWorkspace.ts b/frontend/src/hooks/documents/useDocumentsWorkspace.ts
index ae983cd..b881326 100644
--- a/frontend/src/hooks/documents/useDocumentsWorkspace.ts
+++ b/frontend/src/hooks/documents/useDocumentsWorkspace.ts
@@ -338,7 +338,6 @@ const useDocumentsWorkspace = ({
     isInvalidFolderDrop,
   } = useFolderTree({
     initialSelectedFolder: routeFolderId || 'root',
-    apiClient,
     tenantIdRef,
     documentsSortFieldRef: activeSortFieldRef,
     documentsSortDirectionRef: activeSortDirectionRef,
@@ -506,7 +505,6 @@ const useDocumentsWorkspace = ({
     registerPasskey,
     revokePasskey,
   } = useWorkspaceTaxonomies({
-    apiClient,
     notifyApiError,
     setStatusMessage,
     tagManager,
@@ -544,7 +542,6 @@ const useDocumentsWorkspace = ({
     handleBulkTagRemoveFromDetail,
     handleBulkSelectionReanalyze,
   } = useDocumentTagging({
-    apiClient,
     tags,
     tagManager,
     refreshTags,
@@ -562,7 +559,6 @@ const useDocumentsWorkspace = ({
     clearUploadQueue,
     resetUploadsState,
   } = useDocumentUploads({
-    apiClient,
     token,
     selectedFolder,
     currentFolderName,
@@ -1124,7 +1120,6 @@ const useDocumentsWorkspace = ({
   });
 
   const { handleTenantSelect } = useTenantManager({
-    apiClient,
     appDispatch,
     currentTenantId,
     resetWorkspaceState,
diff --git a/frontend/src/hooks/documents/useFolderTree.ts b/frontend/src/hooks/documents/useFolderTree.ts
index c0a8917..76b300c 100644
--- a/frontend/src/hooks/documents/useFolderTree.ts
+++ b/frontend/src/hooks/documents/useFolderTree.ts
@@ -1,4 +1,5 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
+import { getFolderTree, listFolderContents } from '../../lib/apiClient';
 import type { Dispatch, MutableRefObject, SetStateAction } from 'react';
 import { createRootNode, DEFAULT_FOLDER_NAME } from '../../app/workspaceUtils';
 import {
@@ -43,10 +44,6 @@ interface FolderTreeNode extends FolderSummary {
   hasChildren?: boolean;
 }
 
-interface ApiClient {
-  get<T = FolderContentsEntry>(path: string, config?: { params?: Record<string, unknown> }): Promise<{ data: T }>;
-}
-
 interface SelectionHelpers {
   focusedDocumentId: Identifier | null;
   setFocusedDocumentId: Dispatch<SetStateAction<Identifier | null>>;
@@ -58,7 +55,6 @@ interface SelectionHelpers {
 
 interface UseFolderTreeOptions {
   initialSelectedFolder?: FolderId;
-  apiClient: ApiClient;
   tenantIdRef: MutableRefObject<Identifier | null>;
   documentsSortFieldRef: MutableRefObject<string>;
   documentsSortDirectionRef: MutableRefObject<string>;
@@ -75,7 +71,6 @@ interface FolderOption {
 
 const useFolderTree = ({
   initialSelectedFolder = 'root',
-  apiClient,
   tenantIdRef,
   documentsSortFieldRef,
   documentsSortDirectionRef,
@@ -89,6 +84,52 @@ const useFolderTree = ({
     return new Map([[rootNode.id, rootNode]]);
   });
 
+  useEffect(() => {
+    const fetchTree = async () => {
+      try {
+        const data = await getFolderTree();
+        setFolderNodes((prev) => {
+          const next = new Map(prev);
+          const rootChildren: FolderId[] = [];
+
+          data.forEach((item) => {
+            const id = item.id as FolderId;
+            const parentId = (item.parent_id || 'root') as FolderId;
+            const children = (item.children || []).map((c) => c as FolderId);
+
+            next.set(id, {
+              id,
+              name: item.name,
+              parentId,
+              children,
+              expanded: false,
+              loaded: true,
+              hasChildren: children.length > 0,
+            });
+
+            if (parentId === 'root') {
+              rootChildren.push(id);
+            }
+          });
+
+          const root = next.get('root');
+          if (root) {
+            next.set('root', {
+              ...(root as FolderTreeNode),
+              children: rootChildren,
+              hasChildren: rootChildren.length > 0,
+              loaded: true,
+            });
+          }
+          return next;
+        });
+      } catch (error) {
+        console.error('Failed to fetch folder tree', error);
+      }
+    };
+    fetchTree();
+  }, []);
+
   const [selectedFolder, setSelectedFolder] = useState<FolderId>(initialSelectedFolder || 'root');
   const [currentFolder, setCurrentFolder] = useState<FolderSummary | null>(null);
   const [currentSubfolders, setCurrentSubfolders] = useState<FolderSummary[]>([]);
@@ -245,8 +286,7 @@ const useFolderTree = ({
         params.sort = sortField;
         params.dir = sortDirection;
       }
-      const requestConfig = Object.keys(params).length ? { params } : {};
-      const { data } = await apiClient.get<FolderContentsEntry>(`/folders/${path}/contents`, requestConfig);
+      const data = await listFolderContents<FolderContentsEntry>(path, params);
       const childFolders = Array.isArray(data.subfolders) ? data.subfolders : [];
       const childIds = childFolders
         .map((child) => (child?.id ?? null) as FolderId | null)
@@ -359,7 +399,6 @@ const useFolderTree = ({
       return enriched;
     },
     [
-      apiClient,
       documentsSortDirectionRef,
       documentsSortFieldRef,
       tenantIdRef,
diff --git a/frontend/src/hooks/documents/useTags.ts b/frontend/src/hooks/documents/useTags.ts
index baa4e5b..c14c145 100644
--- a/frontend/src/hooks/documents/useTags.ts
+++ b/frontend/src/hooks/documents/useTags.ts
@@ -2,19 +2,14 @@ import { MutableRefObject, useCallback, useState } from 'react';
 import type { TagId, TenantId } from '../../types/identifiers';
 import type { Tag } from '../../types/documents';
 
-type ApiClient = {
-  get: (path: string) => Promise<{ data: unknown }>
-  post: (path: string, body: unknown) => Promise<{ data: unknown }>
-  patch: (path: string, body: unknown) => Promise<{ data: unknown }>
-  delete: (path: string) => Promise<{ data: unknown }>
-};
+import { listTags, updateTag, createTag, deleteTag } from '../../lib/apiClient';
 
 interface TagManagerInterface {
   buildPayload: (input: { label?: string; color?: string | null }) => { label: string; color: string | null };
 }
 
 interface UseTagsOptions {
-  apiClient: ApiClient;
+  // apiClient removed
   notifyApiError: (error: unknown, fallback: string) => void;
   setStatusMessage: (message: string, variant?: string) => void;
   tagManager: TagManagerInterface;
@@ -24,7 +19,7 @@ interface UseTagsOptions {
 }
 
 const useTags = ({
-  apiClient,
+  // apiClient removed
   notifyApiError,
   setStatusMessage,
   tagManager,
@@ -37,7 +32,7 @@ const useTags = ({
   const refreshTags = useCallback(async () => {
     const requestTenantId = tenantIdRef.current;
     try {
-      const { data } = await apiClient.get('/tags');
+      const data = await listTags();
       if (tenantIdRef.current !== requestTenantId) {
         return;
       }
@@ -48,7 +43,7 @@ const useTags = ({
       }
       notifyApiError(error, 'Unable to load tags.');
     }
-  }, [apiClient, notifyApiError, tenantIdRef]);
+  }, [notifyApiError, tenantIdRef]);
 
   const handleTagUpdate = useCallback(
     async (tagId: TagId, changes: { label?: string; color?: string | null }) => {
@@ -69,7 +64,7 @@ const useTags = ({
       }
 
       try {
-        await apiClient.patch(`/tags/${tagId}`, payload);
+        await updateTag(tagId, payload);
         await refreshTags();
         setStatusMessage('Tag updated.', 'success');
         return true;
@@ -79,14 +74,14 @@ const useTags = ({
         throw new Error(message);
       }
     },
-    [apiClient, notifyApiError, refreshTags, setStatusMessage],
+    [notifyApiError, refreshTags, setStatusMessage],
   );
 
   const handleTagCreate = useCallback(
     async ({ label, color }: { label?: string; color?: string | null } = {}) => {
       const payload = tagManager.buildPayload({ label, color });
       try {
-        await apiClient.post('/tags', payload);
+        await createTag(payload);
         await refreshTags();
         setStatusMessage('Tag created.', 'success');
       } catch (error) {
@@ -95,7 +90,7 @@ const useTags = ({
         throw new Error(message);
       }
     },
-    [apiClient, notifyApiError, refreshTags, setStatusMessage, tagManager],
+    [notifyApiError, refreshTags, setStatusMessage, tagManager],
   );
 
   const handleTagDelete = useCallback(
@@ -105,7 +100,7 @@ const useTags = ({
       }
 
       try {
-        await apiClient.delete(`/tags/${tagId}`);
+        await deleteTag(tagId);
         setActiveTagFilters((prev) => prev.filter((id) => id !== tagId));
 
         const stripTagFromDoc = (doc: any) => {
@@ -130,7 +125,7 @@ const useTags = ({
         throw new Error(message);
       }
     },
-    [apiClient, mapDocumentCaches, notifyApiError, refreshTags, setActiveTagFilters, setStatusMessage],
+    [mapDocumentCaches, notifyApiError, refreshTags, setActiveTagFilters, setStatusMessage],
   );
 
   return {
diff --git a/frontend/src/hooks/documents/useTenantManager.ts b/frontend/src/hooks/documents/useTenantManager.ts
index d08b57a..d73135c 100644
--- a/frontend/src/hooks/documents/useTenantManager.ts
+++ b/frontend/src/hooks/documents/useTenantManager.ts
@@ -2,11 +2,7 @@ import { MutableRefObject, useCallback } from 'react';
 import type { NavigateFunction } from 'react-router-dom';
 import type { FolderId, TenantId } from '../../types/identifiers';
 
-interface ApiClient {
-  get: (path: string) => Promise<{ data: unknown }>;
-  post: (path: string, body?: unknown) => Promise<{ data: any }>;
-  defaults: { headers: { common: Record<string, unknown> } };
-}
+import { api, listTenants, switchTenant } from '../../lib/apiClient';
 
 interface TenantOption {
   id?: TenantId;
@@ -14,7 +10,6 @@ interface TenantOption {
 }
 
 interface UseTenantManagerOptions {
-  apiClient: ApiClient;
   appDispatch: (action: any) => void;
   currentTenantId: TenantId | null;
   resetWorkspaceState: () => void;
@@ -30,7 +25,6 @@ interface UseTenantManagerOptions {
 }
 
 const useTenantManager = ({
-  apiClient,
   appDispatch,
   currentTenantId,
   resetWorkspaceState,
@@ -53,17 +47,15 @@ const useTenantManager = ({
 
       try {
         if (refreshOnly) {
-          const { data } = await apiClient.get('/tenants');
+          const data = await listTenants();
           appDispatch({
             type: 'SET_TENANTS',
-            tenants: Array.isArray(data) ? data : [],
+            tenants: data,
           });
           return;
         }
 
-        const { data } = await apiClient.post('/auth/select-tenant', {
-          tenant_id: requestedTenantId,
-        });
+        const data = await switchTenant(requestedTenantId);
         if (!data?.access_token) {
           throw new Error('Missing access token in tenant switch response.');
         }
@@ -77,7 +69,7 @@ const useTenantManager = ({
           tenant: data.tenant || null,
         });
 
-        apiClient.defaults.headers.common.Authorization = `Bearer ${data.access_token}`;
+        api.defaults.headers.common.Authorization = `Bearer ${data.access_token}`;
         if (tokenRef) {
           tokenRef.current = data.access_token;
         }
@@ -102,7 +94,6 @@ const useTenantManager = ({
       }
     },
     [
-      apiClient,
       appDispatch,
       currentTenantId,
       handleDocumentsViewModeChange,
diff --git a/frontend/src/hooks/documents/useWorkspaceTaxonomies.ts b/frontend/src/hooks/documents/useWorkspaceTaxonomies.ts
index 261aac1..c2c9e7f 100644
--- a/frontend/src/hooks/documents/useWorkspaceTaxonomies.ts
+++ b/frontend/src/hooks/documents/useWorkspaceTaxonomies.ts
@@ -8,7 +8,6 @@ import useTags from './useTags';
 import type { Identifier } from '../../types/identifiers';
 
 interface UseWorkspaceTaxonomiesArgs {
-  apiClient: any;
   notifyApiError: (error: unknown, fallbackMessage?: string, variant?: string) => void;
   setStatusMessage: (message: string, variant?: string) => void;
   tagManager: TagManager;
@@ -21,7 +20,6 @@ interface UseWorkspaceTaxonomiesArgs {
 }
 
 const useWorkspaceTaxonomies = ({
-  apiClient,
   notifyApiError,
   setStatusMessage,
   tagManager,
@@ -40,7 +38,6 @@ const useWorkspaceTaxonomies = ({
     handleTagDelete,
     setTags,
   } = useTags({
-    apiClient,
     notifyApiError,
     setStatusMessage,
     tagManager,
@@ -71,7 +68,6 @@ const useWorkspaceTaxonomies = ({
     handleCorrespondentDelete,
     setCorrespondents,
   } = useCorrespondents({
-    apiClient,
     notifyApiError,
     setStatusMessage,
     tenantIdRef,
@@ -84,7 +80,6 @@ const useWorkspaceTaxonomies = ({
     handleCorrespondentRemove,
     handleCorrespondentAdd,
   } = useDocumentCorrespondentActions({
-    apiClient,
     correspondents,
     handleCorrespondentCreate,
     notifyApiError,
diff --git a/frontend/src/lib/apiClient.ts b/frontend/src/lib/apiClient.ts
index 85d66e5..9cc76d4 100644
--- a/frontend/src/lib/apiClient.ts
+++ b/frontend/src/lib/apiClient.ts
@@ -1,4 +1,5 @@
 import api from './api';
+export { api };
 import type {
   ApiTokenRecord,
   AssetResponse,
@@ -6,11 +7,12 @@ import type {
   CapabilitySetResponse,
   DownloadLink,
   DocumentResponse,
-  FolderTreeNode,
   Identifier,
   PasskeySummary,
   TenantSnippet,
   TagResponse,
+  CorrespondentResponse,
+  FolderTreeResponseItem,
 } from './apiTypes';
 import type { AxiosError, AxiosInstance, InternalAxiosRequestConfig, AxiosRequestConfig } from 'axios';
 
@@ -56,7 +58,7 @@ const normalizeDownload = (input?: DownloadLink | null): DownloadLink | null =>
 
 export const fetchDocument = async (id: Identifier): Promise<DocumentResponse> => {
   const { data } = await api.get<{ document?: DocumentResponse }>(`/documents/${id}`);
-  const doc = data?.document || (data as unknown as DocumentResponse);
+  const doc = data?.document || (data as DocumentResponse);
   if (doc?.current_version?.download) {
     doc.current_version.download = normalizeDownload(doc.current_version.download);
   }
@@ -77,8 +79,8 @@ export const listDocuments = async (params: Record<string, unknown> = {}): Promi
   return Array.isArray(data) ? data : [];
 };
 
-export const getFolderTree = async (): Promise<FolderTreeNode[]> => {
-  const { data } = await api.get<FolderTreeNode[]>('/folders/tree');
+export const getFolderTree = async (): Promise<FolderTreeResponseItem[]> => {
+  const { data } = await api.get<FolderTreeResponseItem[]>('/folders/tree');
   return Array.isArray(data) ? data : [];
 };
 
@@ -342,4 +344,102 @@ api.interceptors.response.use(
   },
 );
 
+export const uploadDocument = async (
+  formData: FormData,
+): Promise<{ reused?: boolean; document?: unknown; status?: number }> => {
+  const { data, status } = await api.post<{ reused?: boolean; document?: unknown }>('/documents', formData);
+  return { ...data, status };
+};
+
+export const resolveFolderPath = async (
+  payload: { parent_id?: Identifier | null; segments: string[] },
+): Promise<{ folder?: { id?: Identifier | null } }> => {
+  const { data } = await api.post<{ folder?: { id?: Identifier | null } }>('/folders/path', payload);
+  return data;
+};
+
+export const bulkTagDocuments = async (
+  payload: { document_ids: Identifier[]; tag_ids: Identifier[]; action: 'add' | 'remove' },
+): Promise<void> => {
+  await api.post('/documents/bulk/tags', payload);
+};
+
+export const bulkReanalyzeDocuments = async (
+  payload: { document_ids: Identifier[]; force?: boolean },
+): Promise<{ queued?: number }> => {
+  const { data } = await api.post<{ queued?: number }>('/documents/bulk/reanalyze', payload);
+  return data;
+};
+
+export const listTags = async (): Promise<TagResponse[]> => {
+  const { data } = await api.get<TagResponse[]>('/tags');
+  return Array.isArray(data) ? data : [];
+};
+
+export const updateTag = async (
+  tagId: Identifier,
+  payload: { label?: string; color?: string | null },
+): Promise<void> => {
+  await api.patch(`/tags/${tagId}`, payload);
+};
+
+export const deleteTag = async (tagId: Identifier): Promise<void> => {
+  await api.delete(`/tags/${tagId}`);
+};
+
+export const listCorrespondents = async (): Promise<CorrespondentResponse[]> => {
+  const { data } = await api.get<CorrespondentResponse[]>('/correspondents');
+  return Array.isArray(data) ? data : [];
+};
+
+export const createCorrespondent = async (payload: { name: string }): Promise<CorrespondentResponse> => {
+  const { data } = await api.post<CorrespondentResponse>('/correspondents', payload);
+  return data;
+};
+
+export const updateCorrespondent = async (
+  correspondentId: Identifier,
+  payload: { name?: string },
+): Promise<void> => {
+  await api.patch(`/correspondents/${correspondentId}`, payload);
+};
+
+export const deleteCorrespondent = async (correspondentId: Identifier): Promise<void> => {
+  await api.delete(`/correspondents/${correspondentId}`);
+};
+
+export const addDocumentCorrespondent = async (
+  documentId: Identifier,
+  correspondentId: Identifier,
+): Promise<void> => {
+  await api.post(`/documents/${documentId}/correspondents`, {
+    assignments: [{ correspondent_id: correspondentId }],
+    replace: false,
+  });
+};
+
+export const removeDocumentCorrespondent = async (
+  documentId: Identifier,
+  correspondentId: Identifier,
+): Promise<void> => {
+  await api.delete(`/documents/${documentId}/correspondents/${correspondentId}`);
+};
+
+
+
+export const switchTenant = async (tenantId: Identifier): Promise<{ access_token: string; tenant: any; tenants?: any[] }> => {
+  const { data } = await api.post<{ access_token: string; tenant: any; tenants?: any[] }>('/auth/select-tenant', {
+    tenant_id: tenantId,
+  });
+  return data;
+};
+
+export const listFolderContents = async <T = any>(
+  path: string,
+  params?: Record<string, unknown>,
+): Promise<T> => {
+  const { data } = await api.get<T>(`/folders/${path}/contents`, { params });
+  return data;
+};
+
 export type { ApiTokenRecord } from './apiTypes';
diff --git a/frontend/src/lib/apiTypes.ts b/frontend/src/lib/apiTypes.ts
index 0c6d621..7fd1acf 100644
--- a/frontend/src/lib/apiTypes.ts
+++ b/frontend/src/lib/apiTypes.ts
@@ -14,7 +14,7 @@ export interface TagResponse {
   color?: string | null;
 }
 
-interface CorrespondentResponse {
+export interface CorrespondentResponse {
   id: string;
   name: string;
   metadata: Record<string, unknown>;
@@ -69,6 +69,10 @@ export interface FolderTreeNode extends FolderInfo {
   children?: FolderTreeNode[];
 }
 
+export interface FolderTreeResponseItem extends FolderInfo {
+  children?: string[];
+}
+
 export interface CapabilitySetResponse {
   id: string;
   slug: string;
diff --git a/frontend/src/styles/status-toast.css b/frontend/src/styles/status-toast.css
index c299c43..f248ce1 100644
--- a/frontend/src/styles/status-toast.css
+++ b/frontend/src/styles/status-toast.css
@@ -1,6 +1,6 @@
 .status-toast-container {
     position: fixed;
-    top: 2rem;
+    top: 3rem;
     left: 50%;
     transform: translateX(-50%);
     z-index: 5000000;