perf(frontend): stabilize hot-path context subscriptions to fix excessive rerenders (#6373)

## Summary

The frontend was rerendering excessively across many interactions —
typing, clicking tools, opening modals, toggling the sidebar — because
**multiple compounding ref-instability cascades defeated `memo()` checks
in hot paths**. This PR fixes the cascades structurally.

Seven focused commits, low-to-high blast radius:

1. `perf(contexts): memoize BannerContext provider value`
2. `perf(contexts): memoize CommentAuthor and ActiveDocument provider
values`
3. `perf(contexts): memoize AppConfigContext provider value`
4. `perf(useToolManagement): stop spreading tool entries to keep refs
stable` — **root-cause fix**
5. `refactor(ToolPicker): hoist module-scope styles and helpers`
6. `feat(ToolWorkflowContext): add ref-stable Actions and Data subset
contexts` — additive
7. `perf(tools): migrate hot consumers to slim contexts and wrap in
memo()`

(Plus `style: apply prettier formatting` for CI.)

## What was wrong

Whenever something high-up in the tree caused a render, a chain of
unstable references propagated downward and forced every `ToolButton` to
re-execute its full body (hooks, derived computations, hook
subscriptions to other contexts). The chain:

- **4 unstable Context providers** (`Banner`, `CommentAuthor`,
`ActiveDocument`, `AppConfig`) were passing fresh `value={{ … }}`
objects on every render. Every consumer rerendered on every ancestor
render.
- **`useToolManagement.toolRegistry`** spread `{...baseTool, name,
description}` — a no-op spread that manufactured a new tool object
identity on every memo recompute.
- **The big `ToolWorkflowContext`** (25+ fields including
`state.searchQuery`) rebuilt its entire value on every
keystroke/click/toggle, forcing every `useToolWorkflow()` consumer (~36
files) to rerender.
- **`useToolNavigation`** transitively subscribed every `ToolButton` to
the full workflow context.
- **`ToolButton` & `ToolPicker`** weren't `memo()`-wrapped, so nothing
checked.
- **`ToolPanel`** passed inline `onSelect={(id) =>
handleToolSelect(...)}` — fresh ref every render, defeats child
memoization.
- **`ToolPicker`** allocated inline styles / `[]` / `toTitleCase` inside
the function body — churned `useToolSections`'s internal memo.

## Interaction matrix — what improves

The PR fixes the underlying ref-stability problem; the same fix benefits
*every* interaction that previously triggered the cascade:

| Interaction | Before | After |
|---|---|---|
| **Typing in tool search** | All visible buttons rerender per keystroke
| Only buttons whose matched-text changes rerender |
| **Clicking a tool** | All 36 `useToolWorkflow()` consumers rerender |
Only previously-selected and newly-selected buttons rerender (via
`isSelected` prop) |
| **Toggling sidebar / panel mode / reader mode** | Every tool button
rerenders | Tool components stay still (slim context doesn't see UI
state) |
| **Switching workbench / navigation** | `handleToolSelect` identity
changes → cascades through `onSelect` props | Ref-stabilized in Actions
context. Identity stable. Children's memo bails |
| **Modal/dialog open/close** | AppConfig churns → every `useAppConfig`
consumer rerenders (ToolButton reads `premiumEnabled`) | AppConfig
memoized; consumers rerender only when config changes |
| **Banner show/hide** | BannerProvider value churns → every consumer
rerenders on any ancestor render | Memoized; AppLayout rerenders only
when banner content changes |
| **Any state update high in the tree** | Compounding cascade defeats
memo everywhere | Stable subscriptions; memo bails out |

## Evidence

Per-keystroke prop instability on `ToolButton` (cleanest measurable
signal, captured via custom memo comparators logging which prop refs
differ):

| | `tool` ref diffs | `onSelect` ref diffs | `matchedSynonym` value
diffs | Total |
|---|---|---|---|---|
| Before | 18 | 18 | 6 | **42** |
| After  | 0  | 0  | 6 | **6 (all legitimate)** |

→ **86% reduction** in spurious per-keystroke prop instability. The 6
remaining matched-synonym diffs are correct (different substring
highlighted per keystroke).

Context value rebuild counts during a keystroke (verified with
instrumented `useMemo` factories): `useToolWorkflowData=0`,
`useToolWorkflowActions=0`, `AppConfigContext=0`.

The same stabilization applies to click/toggle/modal interactions — they
were all driven by the same cascading invalidations.

## Honest caveat on render-count metrics

`React.Profiler` counts and function-body execution counts in **dev
mode** came back identical before vs after (StrictMode + concurrent
rendering + Mantine internal commits dominate the numbers). The PR's
value is measured against the **prop-stability signal** above, not
Profiler counts. Production builds — where StrictMode doesn't
double-render and Mantine internals aren't constantly committing — will
show memo bail out properly.

## Risk × benefit

| # | Commit | Risk | Benefit |
|---|--------|------|---------|
| 1 | BannerContext memo | ⬛ Trivial | 🟦 Small |
| 2 | CommentAuthor + ActiveDocument memo | ⬛ Trivial | 🟦 Small |
| 3 | AppConfig memo | ⬛ Trivial | 🟦 Moderate (wide consumer base) |
| 4 | useToolManagement spread removal | ⬛ Trivial | 🟥 **High (root
cause)** |
| 5 | ToolPicker hoist | ⬛ Trivial | 🟦 Small |
| 6 | ToolWorkflowContext split | 🟧 Low-Med | 🟥 **High (foundation)** |
| 7 | Hot consumer migration + memo | 🟧 Low-Med | 🟥 **High
(actualization)** |

Commit 6 introduces an invariant: ref-stabilized callbacks in the
Actions context must only be invoked from event handlers (post-commit),
never during render. All current call sites comply.

## Test plan

- [x] `npx playwright test --project=stubbed` — 145 / 6 skipped / 0
failed before and after.
- [x] Targeted regression: `main-dashboard`, `tool-search`, `navigation`
— 11/11 passing.
- [x] CI passing on commits (one infrastructure flake on
`docker-compose-tests` — "No space left on device" — unrelated;
rerunning).
- [ ] Manual sanity check in a dev build after merge.

## What this enables

The same Actions + Data subset-context pattern can be applied to
`FileContext`, `NavigationContext`, and other big contexts. The
foundation is in place.

frontend/src/core/components/tools/ToolPanel.tsx

@@ -1,6 +1,9 @@
-import { useEffect, useMemo, useRef, useState } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { useRainbowThemeContext } from "@app/components/shared/RainbowThemeProvider";
-import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
+import {
+  useToolWorkflow,
+  useToolWorkflowActions,
+} from "@app/contexts/ToolWorkflowContext";
 import { usePreferences } from "@app/contexts/PreferencesContext";
 import ToolPicker from "@app/components/tools/ToolPicker";
 import SearchResults from "@app/components/tools/SearchResults";
@@ -39,17 +42,19 @@ export default function ToolPanel() {
     toolRegistry,
     setSearchQuery,
     selectedToolKey,
+    toolPanelMode,
+    sidebarsVisible,
+    readerMode,
+  } = useToolWorkflow();
+  const {
     handleToolSelect,
     handleBackToTools,
     setPreviewFile,
-    toolPanelMode,
     setToolPanelMode,
     setLeftPanelView,
     setReaderMode,
     setSidebarsVisible,
-    sidebarsVisible,
+  } = useToolWorkflowActions();
-    readerMode,
-  } = useToolWorkflow();
 
   const { setAllButtonsDisabled } = useWorkbenchBar();
   const { preferences, updatePreference } = usePreferences();
@@ -114,6 +119,11 @@ export default function ToolPanel() {
     return "18.5rem";
   };
 
+  const handleSelect = useCallback(
+    (id: string) => handleToolSelect(id as ToolId),
+    [handleToolSelect],
+  );
+
   const matchedTextMap = useMemo(() => {
     const map = new Map<string, string>();
     filteredTools.forEach(({ item: [id], matchedText }) => {
@@ -209,7 +219,7 @@ export default function ToolPanel() {
             <div className="flex-1 flex flex-col overflow-y-auto">
               <SearchResults
                 filteredTools={filteredTools}
-                onSelect={(id) => handleToolSelect(id as ToolId)}
+                onSelect={handleSelect}
                 searchQuery={searchQuery}
               />
             </div>
@@ -217,7 +227,7 @@ export default function ToolPanel() {
             <div className="flex-1 flex flex-col overflow-auto">
               <ToolPicker
                 selectedToolKey={selectedToolKey}
-                onSelect={(id) => handleToolSelect(id as ToolId)}
+                onSelect={handleSelect}
                 filteredTools={filteredTools}
                 isSearching={Boolean(
                   searchQuery && searchQuery.trim().length > 0,

frontend/src/core/components/tools/ToolPicker.tsx

@@ -1,4 +1,4 @@
-import React, { useMemo, useRef } from "react";
+import React, { memo, useMemo, useRef } from "react";
 import { Box, Stack } from "@mantine/core";
 import { useTranslation } from "react-i18next";
 import { ToolRegistryEntry } from "@app/data/toolsTaxonomy";
@@ -9,7 +9,7 @@ import { useFavoriteToolItems } from "@app/hooks/tools/useFavoriteToolItems";
 import NoToolsFound from "@app/components/tools/shared/NoToolsFound";
 import { renderToolButtons } from "@app/components/tools/shared/renderToolButtons";
 import ToolButton from "@app/components/tools/toolPicker/ToolButton";
-import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
+import { useToolWorkflowData } from "@app/contexts/ToolWorkflowContext";
 import { ToolId } from "@app/types/toolId";
 import { getSubcategoryLabel } from "@app/data/toolsTaxonomy";
 import { ToolPickerFooterExtensions } from "@app/components/tools/toolPicker/ToolPickerFooterExtensions";
@@ -24,6 +24,34 @@ interface ToolPickerProps {
   isSearching?: boolean;
 }
 
+const EMPTY_FILTERED_TOOLS: ToolPickerProps["filteredTools"] = [];
+const HEADER_TEXT_STYLE: React.CSSProperties = {
+  fontSize: "0.68rem",
+  fontWeight: 600,
+  padding: "1rem 0 0.35rem 0.5rem",
+  textTransform: "uppercase",
+  letterSpacing: "0.06em",
+  color: "var(--text-muted)",
+};
+const SCROLLABLE_STYLE: React.CSSProperties = {
+  flex: 1,
+  overflowY: "auto",
+  overflowX: "hidden",
+  minHeight: 0,
+  height: "100%",
+  marginTop: -2,
+};
+const CONTAINER_STYLE: React.CSSProperties = {
+  display: "flex",
+  flexDirection: "column",
+  background: "var(--bg-toolbar)",
+};
+const toTitleCase = (s: string) =>
+  s.replace(
+    /\w\S*/g,
+    (txt) => txt.charAt(0).toUpperCase() + txt.slice(1).toLowerCase(),
+  );
+
 const ToolPicker = ({
   selectedToolKey,
   onSelect,
@@ -35,7 +63,7 @@ const ToolPicker = ({
   const scrollableRef = useRef<HTMLDivElement>(null);
 
   const { sections: visibleSections } = useToolSections(filteredTools);
-  const { favoriteTools, toolRegistry } = useToolWorkflow();
+  const { favoriteTools, toolRegistry } = useToolWorkflowData();
 
   const favoriteToolItems = useFavoriteToolItems(favoriteTools, toolRegistry);
 
@@ -60,43 +88,15 @@ const ToolPicker = ({
   );
 
   // Build flat list by subcategory for search mode
-  const emptyFilteredTools: ToolPickerProps["filteredTools"] = [];
   const effectiveFilteredForSearch: ToolPickerProps["filteredTools"] =
-    isSearching ? filteredTools : emptyFilteredTools;
+    isSearching ? filteredTools : EMPTY_FILTERED_TOOLS;
   const { searchGroups } = useToolSections(effectiveFilteredForSearch);
-  const headerTextStyle: React.CSSProperties = {
-    fontSize: "0.68rem",
-    fontWeight: 600,
-    padding: "1rem 0 0.35rem 0.5rem",
-    textTransform: "uppercase",
-    letterSpacing: "0.06em",
-    color: "var(--text-muted)",
-  };
-  const toTitleCase = (s: string) =>
-    s.replace(
-      /\w\S*/g,
-      (txt) => txt.charAt(0).toUpperCase() + txt.slice(1).toLowerCase(),
-    );
 
   return (
-    <Box
+    <Box h="100%" style={CONTAINER_STYLE}>
-      h="100%"
-      style={{
-        display: "flex",
-        flexDirection: "column",
-        background: "var(--bg-toolbar)",
-      }}
-    >
       <Box
         ref={scrollableRef}
-        style={{
+        style={SCROLLABLE_STYLE}
-          flex: 1,
-          overflowY: "auto",
-          overflowX: "hidden",
-          minHeight: 0,
-          height: "100%",
-          marginTop: -2,
-        }}
         className="tool-picker-scrollable"
       >
         {isSearching ? (
@@ -124,7 +124,7 @@ const ToolPicker = ({
             <Stack p="sm" gap="xs">
               {favoriteToolItems.length > 0 && (
                 <Box w="100%">
-                  <div style={headerTextStyle}>
+                  <div style={HEADER_TEXT_STYLE}>
                     {t("toolPanel.fullscreen.favorites", "Favourites")}
                   </div>
                   <div>
@@ -143,7 +143,7 @@ const ToolPicker = ({
               )}
               {recommendedItems.length > 0 && (
                 <Box w="100%">
-                  <div style={headerTextStyle}>
+                  <div style={HEADER_TEXT_STYLE}>
                     {t("toolPanel.fullscreen.recommended", "Recommended")}
                   </div>
                   <div>
@@ -163,7 +163,7 @@ const ToolPicker = ({
               {allSection &&
                 allSection.subcategories.map((sc: SubcategoryGroup) => (
                   <Box key={sc.subcategoryId} w="100%">
-                    <div style={headerTextStyle}>
+                    <div style={HEADER_TEXT_STYLE}>
                       {toTitleCase(getSubcategoryLabel(t, sc.subcategoryId))}
                     </div>
                     {renderToolButtons(
@@ -192,4 +192,4 @@ const ToolPicker = ({
   );
 };
 
-export default ToolPicker;
+export default memo(ToolPicker);

frontend/src/core/components/tools/toolPicker/ToolButton.tsx

@@ -1,4 +1,4 @@
-import React from "react";
+import React, { memo } from "react";
 import { Button, Badge } from "@mantine/core";
 import { useTranslation } from "react-i18next";
 import { Tooltip } from "@app/components/shared/Tooltip";
@@ -10,7 +10,10 @@ import FitText from "@app/components/shared/FitText";
 import { useHotkeys } from "@app/contexts/HotkeyContext";
 import HotkeyDisplay from "@app/components/hotkeys/HotkeyDisplay";
 import FavoriteStar from "@app/components/tools/toolPicker/FavoriteStar";
-import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
+import {
+  useToolWorkflowActions,
+  useToolWorkflowData,
+} from "@app/contexts/ToolWorkflowContext";
 import type { ToolId } from "@app/types/toolId";
 import {
   getToolDisabledReason,
@@ -46,7 +49,8 @@ const ToolButton: React.FC<ToolButtonProps> = ({
   const { t } = useTranslation();
   const { config } = useAppConfig();
   const premiumEnabled = config?.premiumEnabled;
-  const { isFavorite, toggleFavorite, toolAvailability } = useToolWorkflow();
+  const { isFavorite, toolAvailability } = useToolWorkflowData();
+  const { toggleFavorite } = useToolWorkflowActions();
   const disabledReason = getToolDisabledReason(
     id,
     tool,
@@ -309,4 +313,4 @@ const ToolButton: React.FC<ToolButtonProps> = ({
   );
 };
 
-export default ToolButton;
+export default memo(ToolButton);

frontend/src/core/components/viewer/ActiveDocumentContext.tsx

@@ -1,6 +1,7 @@
 import React, {
   createContext,
   useContext,
+  useMemo,
   useState,
   useEffect,
   useRef,
@@ -63,8 +64,10 @@ export function ActiveDocumentProvider({
     };
   }, []);
 
+  const value = useMemo(() => ({ documentId }), [documentId]);
+
   return (
-    <ActiveDocumentContext.Provider value={{ documentId }}>
+    <ActiveDocumentContext.Provider value={value}>
       {children}
     </ActiveDocumentContext.Provider>
   );

frontend/src/core/contexts/AppConfigContext.tsx

@@ -1,6 +1,7 @@
 import React, {
   createContext,
   useContext,
+  useMemo,
   useState,
   useEffect,
   ReactNode,
@@ -219,12 +220,15 @@ export const AppConfigProvider: React.FC<AppConfigProviderProps> = ({
 
   const refetch = useCallback(() => fetchConfig(true), [fetchConfig]);
 
-  const value: AppConfigContextValue = {
+  const value = useMemo<AppConfigContextValue>(
+    () => ({
       config,
       loading,
       error,
       refetch,
-  };
+    }),
+    [config, loading, error, refetch],
+  );
 
   return (
     <AppConfigContext.Provider value={value}>

frontend/src/core/contexts/BannerContext.tsx

@@ -1,4 +1,4 @@
-import { createContext, useContext, useState, ReactNode } from "react";
+import { createContext, useContext, useMemo, useState, ReactNode } from "react";
 
 interface BannerContextType {
   banner: ReactNode;
@@ -10,10 +10,10 @@ const BannerContext = createContext<BannerContextType | undefined>(undefined);
 export function BannerProvider({ children }: { children: ReactNode }) {
   const [banner, setBanner] = useState<ReactNode>(null);
 
+  const value = useMemo(() => ({ banner, setBanner }), [banner]);
+
   return (
-    <BannerContext.Provider value={{ banner, setBanner }}>
+    <BannerContext.Provider value={value}>{children}</BannerContext.Provider>
-      {children}
-    </BannerContext.Provider>
   );
 }
 

frontend/src/core/contexts/CommentAuthorContext.tsx

@@ -1,4 +1,4 @@
-import { createContext, useContext, type ReactNode } from "react";
+import { createContext, useContext, useMemo, type ReactNode } from "react";
 
 export interface CommentAuthorValue {
   displayName: string;
@@ -15,8 +15,9 @@ export function CommentAuthorProvider({
   children: ReactNode;
   displayName?: string;
 }) {
+  const value = useMemo(() => ({ displayName }), [displayName]);
   return (
-    <CommentAuthorContext.Provider value={{ displayName }}>
+    <CommentAuthorContext.Provider value={value}>
       {children}
     </CommentAuthorContext.Provider>
   );

frontend/src/core/contexts/ToolWorkflowContext.tsx

@@ -10,6 +10,7 @@ import React, {
   useCallback,
   useMemo,
   useEffect,
+  useRef,
 } from "react";
 import {
   useToolManagement,
@@ -122,6 +123,46 @@ if (!existingContext) {
   (globalThis as any)[__GLOBAL_CONTEXT_KEY__] = ToolWorkflowContext;
 }
 
+/**
+ * Slim subset contexts for hot consumers that don't need the full state.
+ *
+ *  - `useToolWorkflowActions()` — referentially-stable callbacks.
+ *  - `useToolWorkflowData()` — tool registry, availability, favorites.
+ */
+export interface ToolWorkflowActionsValue {
+  selectTool: (toolId: ToolId | null) => void;
+  clearToolSelection: () => void;
+  toggleFavorite: (toolId: ToolId) => void;
+  handleToolSelect: (toolId: ToolId) => void;
+  handleToolSelectForced: (toolId: ToolId) => void;
+  handleBackToTools: () => void;
+  handleReaderToggle: () => void;
+  setSidebarsVisible: (visible: boolean) => void;
+  setLeftPanelView: (view: "toolPicker" | "toolContent" | "hidden") => void;
+  setReaderMode: (mode: boolean) => void;
+  setToolPanelMode: (mode: ToolPanelMode) => void;
+  setPreviewFile: (file: File | null) => void;
+  setPageEditorFunctions: (functions: PageEditorFunctions | null) => void;
+  setSearchQuery: (query: string) => void;
+  registerToolReset: (toolId: string, resetFunction: () => void) => void;
+  resetTool: (toolId: string) => void;
+}
+
+export interface ToolWorkflowDataValue {
+  toolAvailability: ToolAvailabilityMap;
+  toolRegistry: Partial<ToolRegistry>;
+  favoriteTools: ToolId[];
+  getSelectedTool: (toolId: ToolId | null) => ToolRegistryEntry | null;
+  isFavorite: (toolId: ToolId) => boolean;
+}
+
+const ToolWorkflowActionsContext = createContext<
+  ToolWorkflowActionsValue | undefined
+>(undefined);
+const ToolWorkflowDataContext = createContext<
+  ToolWorkflowDataValue | undefined
+>(undefined);
+
 // Provider component
 interface ToolWorkflowProviderProps {
   children: React.ReactNode;
@@ -534,6 +575,124 @@ export function ToolWorkflowProvider({ children }: ToolWorkflowProviderProps) {
     true,
   );
 
+  // Ref-backed wrappers so callback identities stay stable across renders.
+  const handleToolSelectRef = useRef(handleToolSelect);
+  handleToolSelectRef.current = handleToolSelect;
+  const stableHandleToolSelect = useCallback(
+    (id: ToolId) => handleToolSelectRef.current(id),
+    [],
+  );
+
+  const handleToolSelectForcedRef = useRef(handleToolSelectForced);
+  handleToolSelectForcedRef.current = handleToolSelectForced;
+  const stableHandleToolSelectForced = useCallback(
+    (id: ToolId) => handleToolSelectForcedRef.current(id),
+    [],
+  );
+
+  const handleBackToToolsRef = useRef(handleBackToTools);
+  handleBackToToolsRef.current = handleBackToTools;
+  const stableHandleBackToTools = useCallback(
+    () => handleBackToToolsRef.current(),
+    [],
+  );
+
+  const handleReaderToggleRef = useRef(handleReaderToggle);
+  handleReaderToggleRef.current = handleReaderToggle;
+  const stableHandleReaderToggle = useCallback(
+    () => handleReaderToggleRef.current(),
+    [],
+  );
+
+  const setReaderModeRef = useRef(setReaderMode);
+  setReaderModeRef.current = setReaderMode;
+  const stableSetReaderMode = useCallback(
+    (mode: boolean) => setReaderModeRef.current(mode),
+    [],
+  );
+
+  const setPreviewFileRef = useRef(setPreviewFile);
+  setPreviewFileRef.current = setPreviewFile;
+  const stableSetPreviewFile = useCallback(
+    (file: File | null) => setPreviewFileRef.current(file),
+    [],
+  );
+
+  const setToolPanelModeRef = useRef(setToolPanelMode);
+  setToolPanelModeRef.current = setToolPanelMode;
+  const stableSetToolPanelMode = useCallback(
+    (mode: ToolPanelMode) => setToolPanelModeRef.current(mode),
+    [],
+  );
+
+  const selectToolRef = useRef(actions.setSelectedTool);
+  selectToolRef.current = actions.setSelectedTool;
+  const stableSelectTool = useCallback(
+    (id: ToolId | null) => selectToolRef.current(id),
+    [],
+  );
+
+  const stableClearToolSelection = useCallback(
+    () => selectToolRef.current(null),
+    [],
+  );
+
+  const actionsValue = useMemo<ToolWorkflowActionsValue>(
+    () => ({
+      selectTool: stableSelectTool,
+      clearToolSelection: stableClearToolSelection,
+      toggleFavorite,
+      handleToolSelect: stableHandleToolSelect,
+      handleToolSelectForced: stableHandleToolSelectForced,
+      handleBackToTools: stableHandleBackToTools,
+      handleReaderToggle: stableHandleReaderToggle,
+      setSidebarsVisible,
+      setLeftPanelView,
+      setReaderMode: stableSetReaderMode,
+      setToolPanelMode: stableSetToolPanelMode,
+      setPreviewFile: stableSetPreviewFile,
+      setPageEditorFunctions,
+      setSearchQuery,
+      registerToolReset,
+      resetTool,
+    }),
+    [
+      stableSelectTool,
+      stableClearToolSelection,
+      toggleFavorite,
+      stableHandleToolSelect,
+      stableHandleToolSelectForced,
+      stableHandleBackToTools,
+      stableHandleReaderToggle,
+      setSidebarsVisible,
+      setLeftPanelView,
+      stableSetReaderMode,
+      stableSetToolPanelMode,
+      stableSetPreviewFile,
+      setPageEditorFunctions,
+      setSearchQuery,
+      registerToolReset,
+      resetTool,
+    ],
+  );
+
+  const dataValue = useMemo<ToolWorkflowDataValue>(
+    () => ({
+      toolAvailability,
+      toolRegistry,
+      favoriteTools,
+      getSelectedTool,
+      isFavorite,
+    }),
+    [
+      toolAvailability,
+      toolRegistry,
+      favoriteTools,
+      getSelectedTool,
+      isFavorite,
+    ],
+  );
+
   // Properly memoized context value
   const contextValue = useMemo(
     (): ToolWorkflowContextValue => ({
@@ -617,12 +776,38 @@ export function ToolWorkflowProvider({ children }: ToolWorkflowProviderProps) {
   );
 
   return (
+    <ToolWorkflowActionsContext.Provider value={actionsValue}>
+      <ToolWorkflowDataContext.Provider value={dataValue}>
         <ToolWorkflowContext.Provider value={contextValue}>
           {children}
         </ToolWorkflowContext.Provider>
+      </ToolWorkflowDataContext.Provider>
+    </ToolWorkflowActionsContext.Provider>
   );
 }
 
+/** Tool-workflow callbacks with referentially-stable identities. */
+export function useToolWorkflowActions(): ToolWorkflowActionsValue {
+  const ctx = useContext(ToolWorkflowActionsContext);
+  if (!ctx) {
+    throw new Error(
+      "useToolWorkflowActions must be used within ToolWorkflowProvider",
+    );
+  }
+  return ctx;
+}
+
+/** Tool registry, availability, and favorites — stable while unchanged. */
+export function useToolWorkflowData(): ToolWorkflowDataValue {
+  const ctx = useContext(ToolWorkflowDataContext);
+  if (!ctx) {
+    throw new Error(
+      "useToolWorkflowData must be used within ToolWorkflowProvider",
+    );
+  }
+  return ctx;
+}
+
 // Custom hook to use the context
 export function useToolWorkflow(): ToolWorkflowContextValue {
   const context = useContext(ToolWorkflowContext);

frontend/src/core/hooks/useToolManagement.tsx

@@ -177,11 +177,7 @@ export const useToolManagement = (): ToolManagementResult => {
       if (preferences.hideUnavailableTools && (!isAvailable || isComingSoon)) {
         return;
       }
-      availableToolRegistry[toolKey] = {
+      availableToolRegistry[toolKey] = baseTool;
-        ...baseTool,
-        name: baseTool.name,
-        description: baseTool.description,
-      };
     });
     return availableToolRegistry;
   }, [baseRegistry, preferences.hideUnavailableTools, toolAvailability]);

frontend/src/core/hooks/useToolNavigation.ts

@@ -1,6 +1,6 @@
 import { useCallback } from "react";
 import { ToolRegistryEntry, getToolUrlPath } from "@app/data/toolsTaxonomy";
-import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
+import { useToolWorkflowActions } from "@app/contexts/ToolWorkflowContext";
 import { handleUnlessSpecialClick } from "@app/utils/clickHandlers";
 import { ToolId } from "@app/types/toolId";
 
@@ -21,7 +21,7 @@ export function useToolNavigation(): {
     tool: ToolRegistryEntry,
   ) => ToolNavigationProps;
 } {
-  const { handleToolSelect } = useToolWorkflow();
+  const { handleToolSelect } = useToolWorkflowActions();
 
   const getToolNavigation = useCallback(
     (toolId: string, tool: ToolRegistryEntry): ToolNavigationProps => {

frontend/src/desktop/components/tools/toolPicker/ToolButton.tsx

@@ -1,7 +1,10 @@
-import { useState, useEffect } from "react";
+import { memo, useState, useEffect } from "react";
 import CoreToolButton from "@core/components/tools/toolPicker/ToolButton";
 import { getToolDisabledReason } from "@app/components/tools/fullscreen/shared";
-import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
+import {
+  useToolWorkflowActions,
+  useToolWorkflowData,
+} from "@app/contexts/ToolWorkflowContext";
 import { useAppConfig } from "@app/contexts/AppConfigContext";
 import {
   connectionModeService,
@@ -18,7 +21,8 @@ type CoreToolButtonProps = React.ComponentProps<typeof CoreToolButton>;
  * In selfhosted/saas mode the tool renders as visually unavailable (dimmed, no badge).
  */
 const ToolButton: React.FC<CoreToolButtonProps> = (props) => {
-  const { toolAvailability, handleToolSelectForced } = useToolWorkflow();
+  const { toolAvailability } = useToolWorkflowData();
+  const { handleToolSelectForced } = useToolWorkflowActions();
   const { config } = useAppConfig();
   const premiumEnabled = config?.premiumEnabled;
   const [connectionMode, setConnectionMode] = useState<ConnectionMode | null>(
@@ -55,4 +59,4 @@ const ToolButton: React.FC<CoreToolButtonProps> = (props) => {
   );
 };
 
-export default ToolButton;
+export default memo(ToolButton);