{"version":3,"file":"providerToolSearch.cjs","names":["createMiddleware","isLangChainTool"],"sources":["../../../src/agents/middleware/providerToolSearch.ts"],"sourcesContent":["import type {\n StructuredToolInterface,\n StructuredToolParams,\n ClientTool,\n ServerTool,\n} from \"@langchain/core/tools\";\nimport { isLangChainTool } from \"@langchain/core/utils/function_calling\";\nimport { createMiddleware } from \"../middleware.js\";\nimport type { LanguageModelLike } from \"@langchain/core/language_models/base\";\nimport type {\n ChatModelProvider,\n ConfigurableModel,\n} from \"../../chat_models/universal.js\";\n\ntype ToolName = string;\nexport type ToolIdentifier = ToolName | StructuredToolInterface;\n\nexport type ProviderToolSearchMiddlewareConfig = {\n /**\n * Which tools are deferred; withheld from the model until its tool search surfaces them.\n *\n * Tools already constructed with `extras.defer_loading === true` are deferred\n * regardless of this option; if `searchableTools` is omitted, only those pre-marked\n * tools are deferred.\n */\n searchableTools?: ToolIdentifier[];\n};\n\nconst SERVER_SEARCH_PROVIDERS = [\n \"anthropic\",\n \"openai\",\n] as const satisfies readonly ChatModelProvider[];\n\ntype ServerSearchCapableProvider = (typeof SERVER_SEARCH_PROVIDERS)[number];\ntype DetectedProvider = ServerSearchCapableProvider | \"other\";\n\ntype ServerToolSearchTool = { type: string; name?: string };\n\nconst SERVER_TOOL_SEARCH_TOOLS = {\n anthropic: {\n type: \"tool_search_tool_bm25_20251119\",\n name: \"tool_search_tool_bm25\",\n },\n openai: { type: \"tool_search\" },\n} as const satisfies Record;\n\n/**\n * Provider-side tool search middleware.\n *\n * Leverages server-side tool search: the full client tool catalog is forwarded\n * to the provider, with deferred tools marked `defer_loading` so the provider\n * discloses them on demand via its own search. A tool is deferred when it is\n * named in `searchableTools` or built with `extras.defer_loading: true`.\n *\n * Requires a model with server-side tool search support: OpenAI gpt-5.4+ or Anthropic\n * Claude Sonnet 4+/Opus 4+/Haiku 4.5+. Non-Anthropic/OpenAI providers throw; an\n * in-family model that is too old surfaces the provider's own API error rather\n * than being gated here.\n *\n * @example\n * ```ts\n * import { createAgent, providerToolSearchMiddleware } from \"langchain\";\n * import { ChatAnthropic } from \"@langchain/anthropic\";\n *\n * const agent = createAgent({\n * model: new ChatAnthropic({ model: \"claude-sonnet-4-5\" }),\n * tools: [getWeather, ...nicheTools],\n * middleware: [\n * // Defer the niche tools behind the provider's tool search; the model\n * // discovers them on demand instead of receiving every schema up front.\n * providerToolSearchMiddleware({ searchableTools: nicheTools }),\n * ],\n * });\n * ```\n *\n * @example\n * ```ts\n * import { tool } from \"@langchain/core/tools\";\n * import { createAgent, providerToolSearchMiddleware } from \"langchain\";\n * import { ChatAnthropic } from \"@langchain/anthropic\";\n *\n * // A tool marked `defer_loading` at construction is deferred on its own —\n * // no need to list it in `searchableTools`; the middleware honors the flag.\n * const sendEmail = tool(sendEmailFn, {\n * name: \"send_email\",\n * description: \"Send an email\",\n * schema: sendEmailSchema,\n * extras: { defer_loading: true },\n * });\n *\n * const agent = createAgent({\n * model: new ChatAnthropic({ model: \"claude-sonnet-4-5\" }),\n * tools: [getWeather, sendEmail],\n * middleware: [providerToolSearchMiddleware()],\n * });\n * ```\n *\n * @param config - Configuration options for the middleware\n * @param config.searchableTools - Tools to defer behind tool search\n * @returns A middleware instance that can be used with `createAgent`\n */\nexport function providerToolSearchMiddleware(\n config: ProviderToolSearchMiddlewareConfig = {}\n) {\n const deferNames = toToolNames(config.searchableTools);\n\n return createMiddleware({\n name: \"ProviderToolSearch\",\n wrapModelCall: (request, handler) => {\n const tools = request.tools ?? [];\n\n // Fail fast if we try to defer a tool that is not bound to the model\n if (deferNames.size > 0) {\n const available = tools.filter(isLangChainTool).map((t) => t.name);\n const unknown = [...deferNames].filter(\n (name) => !available.includes(name)\n );\n if (unknown.length > 0) {\n throw new Error(\n `providerToolSearchMiddleware: searchableTools references tool(s) not bound to the model: ${unknown.join(\", \")}`\n );\n }\n }\n\n const provider = getModelProvider(request.model);\n if (!supportsProviderToolSearch(provider)) {\n throw new Error(\n `providerToolSearchMiddleware requires a provider with server-side tool search, but got ${provider}`\n );\n }\n\n // Nothing to defer -> pass thru\n if (!hasDeferredTools(tools, deferNames)) return handler(request);\n\n // For each deferred tool, emit a minimal binding spec carrying `defer_loading`.\n const boundTools = tools.map((tool) =>\n deferToolIfNeeded(tool, deferNames)\n );\n\n const nativeSearchTool = SERVER_TOOL_SEARCH_TOOLS[provider];\n return handler({ ...request, tools: [...boundTools, nativeSearchTool] });\n },\n });\n}\n\nfunction isDeferred(\n tool: unknown,\n deferNames: Set\n): tool is StructuredToolParams {\n return (\n isLangChainTool(tool) &&\n (tool.extras?.defer_loading === true || deferNames.has(tool.name))\n );\n}\n\nfunction hasDeferredTools(\n tools: readonly (ClientTool | ServerTool)[],\n deferNames: Set\n): boolean {\n return tools.some((tool) => isDeferred(tool, deferNames));\n}\n\n/**\n * If a tool should be deferred, return a minimal binding spec carrying `defer_loading`.\n * Otherwise return it as-is\n */\nfunction deferToolIfNeeded(\n tool: ClientTool | ServerTool,\n deferNames: Set\n): ClientTool | ServerTool {\n if (!isDeferred(tool, deferNames)) return tool;\n return {\n name: tool.name,\n description: tool.description,\n schema: tool.schema,\n extras: { ...tool.extras, defer_loading: true },\n };\n}\n\n/** Flatten a list of tool names/instances into a set of tool names. */\nfunction toToolNames(tools: ToolIdentifier[] = []): Set {\n return new Set(tools.map((t) => (typeof t === \"string\" ? t : t.name)));\n}\n\nfunction getModelProvider(model: LanguageModelLike): DetectedProvider {\n const name = model.getName();\n const configured =\n name === \"ConfigurableModel\"\n ? 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