feat(askai): add compatibility with algolia mcp search tool [DASH-2294] (#2862)

## Summary
Fixes DASH-2294
Add compatibility with the Algolia MCP search tool (`algolia_search_index_${string}`) in AskAI.

## Changes
- Add `AlgoliaMCPSearchTool` type to handle the Algolia MCP server search tool
- Refactor how number of hits are retrieved in `ToolCall` into a `getNumberOfHits` helper

## Test plan
- Added unit tests for modified code ✅

packages/docsearch-react/src/Sidepanel/ConversationScreen.tsx

@@ -8,7 +8,7 @@ import { MemoizedMarkdown } from '../MemoizedMarkdown';
 import type { StoredSearchPlugin } from '../stored-searches';
 import { ToolCall, type ToolCallTranslations } from '../ToolCall';
 import type { StoredAskAiState } from '../types';
-import type { AIMessage } from '../types/AskiAi';
+import { isAIToolPart, type AIMessage } from '../types/AskiAi';
 import { extractLinksFromMessage, getMessageContent } from '../utils/ai';
 import { groupConsecutiveToolResults } from '../utils/groupConsecutiveToolResults';
 
@@ -159,7 +159,7 @@ const ConversationExchange = React.forwardRef<HTMLDivElement, ConversationnExcha
                   return <AggregatedSearchBlock key={index} queries={part.queries} />;
                 }
 
-                if (part.type === 'tool-searchIndex' || part.type === 'tool-algolia_search_index') {
+                if (isAIToolPart(part)) {
                   return (
                     <ToolCall
                       key={index}

packages/docsearch-react/src/ToolCall.tsx

@@ -47,7 +47,7 @@ export function ToolCall({ part, translations, onSearchQueryClick }: ToolCallPro
       );
     case 'output-available': {
       const query = part.type === 'tool-searchIndex' ? part.output.query : part.input.query;
-      const numberOfHits = part.type === 'tool-searchIndex' ? part.output.hits?.length : part.output.nbHits;
+      const numberOfHits = part.output.hits?.length ?? 0;
 
       return (
         <div className="DocSearch-AskAiScreen-MessageContent-Tool Tool--Result">
@@ -73,7 +73,7 @@ export function ToolCall({ part, translations, onSearchQueryClick }: ToolCallPro
             ) : (
               <span className="DocSearch-AskAiScreen-MessageContent-Tool-Query"> &quot;{query || ''}&quot;</span>
             )}{' '}
-            found {numberOfHits || 0} results
+            found {numberOfHits} results
           </span>
         </div>
       );

packages/docsearch-react/src/__tests__/ToolCall.test.tsx

@@ -0,0 +1,71 @@
+import { render, screen } from '@testing-library/react';
+import '@testing-library/jest-dom/vitest';
+import React from 'react';
+import { describe, it, expect } from 'vitest';
+
+import { ToolCall, type ToolCallTranslations } from '../ToolCall';
+import type { AIToolPart } from '../types/AskiAi';
+
+const TRANSLATIONS: ToolCallTranslations = {
+  preToolCallText: 'Searching for',
+  searchingText: 'Searching...',
+  toolCallResultText: 'Searched',
+};
+
+describe('ToolCall', () => {
+  describe('number of hits rendering', () => {
+    it.each([
+      {
+        description: 'tool-searchIndex with hits array',
+        part: {
+          type: 'tool-searchIndex',
+          toolCallId: 'id-1',
+          state: 'output-available',
+          input: { query: 'test' },
+          output: { query: 'test', hits: [{}, {}, {}] },
+        },
+        expectedHits: 3,
+      },
+      {
+        description: 'tool-searchIndex with empty hits',
+        part: {
+          type: 'tool-searchIndex',
+          toolCallId: 'id-2',
+          state: 'output-available',
+          input: { query: 'test' },
+          output: { query: 'test', hits: [] },
+        },
+        expectedHits: 0,
+      },
+      {
+        description: 'tool-algolia_search_index with nbHits',
+        part: {
+          type: 'tool-algolia_search_index',
+          toolCallId: 'id-3',
+          state: 'output-available',
+          input: { index: 'docs', query: 'test', number_of_results: 10, facet_filters: null },
+          output: { hits: [{}, {}] },
+        },
+        expectedHits: 2,
+      },
+      {
+        description: 'tool-algolia_search_index_custom with results array',
+        part: {
+          type: 'tool-algolia_search_index_custom',
+          toolCallId: 'id-4',
+          state: 'output-available',
+          input: { query: 'test' },
+          output: { hits: [{}] },
+        },
+        expectedHits: 1,
+      },
+    ] satisfies Array<{ description: string; part: AIToolPart; expectedHits: number }>)(
+      'displays $expectedHits results for $description',
+      ({ part, expectedHits }) => {
+        render(<ToolCall part={part} translations={TRANSLATIONS} />);
+
+        expect(screen.getByText(`found ${expectedHits} results`, { exact: false })).toBeInTheDocument();
+      },
+    );
+  });
+});

packages/docsearch-react/src/types/AskiAi.ts

@@ -27,7 +27,19 @@ export interface AgentStudioSearchTool {
   };
 }
 
+export interface AlgoliaMCPSearchTool {
+  input: {
+    query: string;
+  };
+  output: {
+    hits?: any[];
+    nbHits?: number;
+  };
+}
+
 type Tools = {
+  [K in `algolia_search_index_${string}`]: AlgoliaMCPSearchTool;
+} & {
   searchIndex: SearchIndexTool;
   algolia_search_index: AgentStudioSearchTool;
 };
@@ -37,3 +49,7 @@ export type AIMessage = UIMessage<{ stopped?: boolean }, UIDataTypes, Tools>;
 export type AIMessagePart = UIMessagePart<UIDataTypes, Tools>;
 
 export type AIToolPart = ToolUIPart<Tools>;
+
+export function isAIToolPart(part: AIMessagePart): part is AIToolPart {
+  return part.type.startsWith('tool-');
+}

packages/docsearch-react/src/types/__tests__/AskiAi.test.ts

@@ -0,0 +1,41 @@
+import { describe, it, expect } from 'vitest';
+
+import type { AIMessagePart } from '../AskiAi';
+import { isAIToolPart } from '../AskiAi';
+
+describe('isAIToolPart', () => {
+  it.each([
+    {
+      part: {
+        type: 'tool-searchIndex',
+        toolCallId: 'id-1',
+        state: 'output-available',
+        input: { query: 'test' },
+        output: { hits: [] },
+      },
+      expected: true,
+    },
+    {
+      part: {
+        type: 'tool-algolia_search_index',
+        toolCallId: 'id-2',
+        state: 'input-streaming',
+        input: {},
+      },
+      expected: true,
+    },
+    {
+      part: { type: 'text', text: 'Hello' },
+      expected: false,
+    },
+    {
+      part: { type: 'reasoning', text: 'Thinking...' },
+      expected: false,
+    },
+  ] satisfies Array<{ part: AIMessagePart; expected: boolean }>)(
+    'returns $expected for $part.type',
+    ({ part, expected }) => {
+      expect(isAIToolPart(part)).toBe(expected);
+    },
+  );
+});