Backport: fix(xai): support Responses API streaming events and custom_tool_call type #10610
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… type (#10523) Add missing schema validation for xAI Responses API server-side tools: - Add custom_tool_call type to outputItemSchema - Make toolCallSchema fields optional for in_progress states - Add input field for custom_tool_call (vs arguments) - Add action field for in_progress tool execution states - Add 12 streaming event types for tool lifecycle: - web_search_call: in_progress, searching, completed - x_search_call: in_progress, searching, completed - code_execution_call: in_progress, executing, completed - code_interpreter_call: in_progress, executing, completed Fixes validation errors ('Invalid JSON response', 'No matching discriminator') when using xai.responses() with xai.tools.webSearch(), xai.tools.xSearch(), or xai.tools.codeExecution(). ## Background The xAI Responses API with server-side tools (`web_search`, `x_search`, `code_execution`) was failing with validation errors when using the Vercel AI SDK: ``` AI_TypeValidationError: Invalid JSON response Error: No matching discriminator for output[].type ``` **Root cause**: The xAI API returns response formats that were not included in the SDK's Zod validation schemas: 1. **`custom_tool_call` type** - Server-side tool calls use this type instead of the standard tool call types 2. **Streaming progress events** - Events like `response.web_search_call.in_progress`, `response.web_search_call.searching`, `response.web_search_call.completed` were not recognized 3. **Optional fields during execution** - During `in_progress` state, fields like `name`, `arguments`, `call_id` are undefined 4. **Different field names** - `custom_tool_call` uses `input` field instead of `arguments` ## Summary Updated `packages/xai/src/responses/xai-responses-api.ts` to support the complete xAI Responses API format: ### 1. Added `custom_tool_call` Type Support **Type definition** (`XaiResponsesToolCall`): ```typescript export type XaiResponsesToolCall = { type: | 'function_call' | 'web_search_call' | 'x_search_call' | 'code_interpreter_call' | 'custom_tool_call'; // ✅ Added id: string; call_id?: string; // ✅ Made optional name?: string; // ✅ Made optional arguments?: string; // ✅ Made optional input?: string; // ✅ Added for custom_tool_call status: string; action?: any; // ✅ Added for in_progress state }; ``` **Schema** (`outputItemSchema`): ```typescript z.object({ type: z.literal('custom_tool_call'), ...toolCallSchema.shape, }), ``` ### 2. Made Tool Call Fields Optional Updated `toolCallSchema` to handle in-progress states where fields are undefined: ```typescript const toolCallSchema = z.object({ name: z.string().optional(), // Was required arguments: z.string().optional(), // Was required input: z.string().optional(), // ✅ New (for custom_tool_call) call_id: z.string().optional(), // Was required id: z.string(), status: z.string(), action: z.any().optional(), // ✅ New (for in_progress state) }); ``` ### 3. Added 12 Streaming Event Types Added to `xaiResponsesChunkSchema` for complete tool execution lifecycle: **Web Search:** - `response.web_search_call.in_progress` - `response.web_search_call.searching` - `response.web_search_call.completed` **X Search:** - `response.x_search_call.in_progress` - `response.x_search_call.searching` - `response.x_search_call.completed` **Code Execution:** - `response.code_execution_call.in_progress` - `response.code_execution_call.executing` - `response.code_execution_call.completed` **Code Interpreter:** - `response.code_interpreter_call.in_progress` - `response.code_interpreter_call.executing` - `response.code_interpreter_call.completed` ## Manual Verification Tested all server-side tools with both `generateText()` and `streamText()` to ensure end-to-end functionality: ### ✅ Web Search Tool ```typescript import { xai } from '@ai-sdk/xai'; import { generateText } from 'ai'; const { text, sources } = await generateText({ model: xai.responses('grok-4-fast'), prompt: 'What are the latest developments in AI?', tools: { web_search: xai.tools.webSearch(), }, }); console.log(text); // Comprehensive response console.log(sources); // Array of URL citations ``` **Result**: ✅ Returned comprehensive response with 14 URL citations, no validation errors ### ✅ X Search Tool ```typescript import { xai } from '@ai-sdk/xai'; import { generateText } from 'ai'; const { text, sources } = await generateText({ model: xai.responses('grok-4-fast'), prompt: 'What are people saying about AI on X this week?', tools: { x_search: xai.tools.xSearch({ allowedXHandles: ['elonmusk', 'xai'], fromDate: '2025-11-18', toDate: '2025-11-24', enableImageUnderstanding: true, enableVideoUnderstanding: true, }), }, }); console.log(text); // Analysis of X discussions console.log(sources); // Array of X post citations ``` **Result**: ✅ Returned analysis with 16 X post citations, all streaming events properly handled ### ✅ Code Execution Tool ```typescript import { xai } from '@ai-sdk/xai'; import { generateText } from 'ai'; const { text } = await generateText({ model: xai.responses('grok-4-fast'), prompt: 'Calculate the factorial of 20 using Python', tools: { code_execution: xai.tools.codeExecution(), }, }); console.log(text); // Result with code execution details ``` **Result**: ✅ Computed result with execution details, no validation errors ### ✅ Multiple Tools with Streaming ```typescript import { xai } from '@ai-sdk/xai'; import { streamText } from 'ai'; const { fullStream, usage: usagePromise } = streamText({ model: xai.responses('grok-4-fast'), system: 'You are an AI research assistant.', tools: { web_search: xai.tools.webSearch(), x_search: xai.tools.xSearch(), code_execution: xai.tools.codeExecution(), }, prompt: 'Research prompt caching in LLMs and explain how it reduces costs', }); const sources = new Set<string>(); let lastToolName = ''; for await (const event of fullStream) { switch (event.type) { case 'tool-call': lastToolName = event.toolName; if (event.providerExecuted) { console.log(`[Calling ${event.toolName} on server...]`); } break; case 'tool-result': console.log(`[${lastToolName} completed]`); break; case 'text-delta': process.stdout.write(event.text); break; case 'source': if (event.sourceType === 'url') { sources.add(event.url); } break; } } const usage = await usagePromise; console.log(`\nSources used: ${sources.size}`); console.log(`Token usage: ${usage.inputTokens} input, ${usage.outputTokens} output`); ``` **Result**: ✅ Full streaming response with web searches, real-time progress updates, and source citations. All streaming events (`tool-call`, `tool-result`, `text-delta`, `source`) work correctly. **Summary of manual testing:** - ✅ All three tool types (web_search, x_search, code_execution) work without validation errors - ✅ Both `generateText()` and `streamText()` work correctly - ✅ Source citations are properly parsed and returned - ✅ Streaming progress events are handled correctly - ✅ No "Invalid JSON response" or "No matching discriminator" errors ## Related issues closes #10607
4 tasks
gr2m
approved these changes
Nov 25, 2025
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This is an automated backport of #10523 to the release-v5.0 branch. FYI @baturyilmaz