claude-code/packages/builtin-tools/src/tools/WebSearchTool/adapters/index.ts

/**
 * Search adapter factory — selects the appropriate backend by checking
 * whether the API base URL points to Anthropic's official endpoint.
 */

import { isFirstPartyAnthropicBaseUrl } from 'src/utils/model/providers.js'
import { ApiSearchAdapter } from './apiAdapter.js'
import { BingSearchAdapter } from './bingAdapter.js'
import { BraveSearchAdapter } from './braveAdapter.js'
import { ExaSearchAdapter } from './exaAdapter.js'
import type { WebSearchAdapter } from './types.js'

export type {
  SearchResult,
  SearchOptions,
  SearchProgress,
  WebSearchAdapter,
} from './types.js'

/**
 * Check if the current session uses a third-party (non-Anthropic) API provider.
 * These providers don't support Anthropic's server_tools (server-side web search),
 * so they must fall back to the Bing scraper adapter.
 */
function isThirdPartyProvider(): boolean {
  return !!(
    process.env.CLAUDE_CODE_USE_OPENAI ||
    process.env.CLAUDE_CODE_USE_GEMINI ||
    process.env.CLAUDE_CODE_USE_GROK
  )
}

let cachedAdapter: WebSearchAdapter | null = null
let cachedAdapterKey: 'api' | 'bing' | 'brave' | 'exa' | null = null

export function createAdapter(): WebSearchAdapter {
  const envAdapter = process.env.WEB_SEARCH_ADAPTER
  // Priority:
  //   1. Explicit env override (WEB_SEARCH_ADAPTER=api|bing|brave)
  //   2. Third-party provider (OpenAI/Gemini/Grok) → bing (no server_tools support)
  //   3. First-party Anthropic API → api (server-side web search + connector_text)
  //   4. Fallback → bing
  const adapterKey =
    envAdapter === 'api' || envAdapter === 'bing' || envAdapter === 'brave' || envAdapter === 'exa'
      ? envAdapter
      : isThirdPartyProvider()
        ? 'bing'
        : isFirstPartyAnthropicBaseUrl()
          ? 'api'
          : 'exa'

  if (cachedAdapter && cachedAdapterKey === adapterKey) return cachedAdapter

  if (adapterKey === 'api') {
    cachedAdapter = new ApiSearchAdapter()
    cachedAdapterKey = 'api'
    return cachedAdapter
  }
  if (adapterKey === 'brave') {
    cachedAdapter = new BraveSearchAdapter()
    cachedAdapterKey = 'brave'
    return cachedAdapter
  }
  if (adapterKey === 'exa') {
    cachedAdapter = new ExaSearchAdapter()
    cachedAdapterKey = 'exa'
    return cachedAdapter
  }

  cachedAdapter = new BingSearchAdapter()
  cachedAdapterKey = 'bing'
  return cachedAdapter
}