ai-sdk-core

name	ai-sdk-core
description	Vercel AI SDK v5 for backend AI (text generation, structured output, tools, agents). Multi-provider. Use for server-side AI or encountering AI_APICallError, AI_NoObjectGeneratedError, streaming failures.
metadata	{"keywords":["ai sdk core","vercel ai sdk","generateText","streamText","generateObject","streamObject","ai sdk node","ai sdk server","zod ai schema","ai tools calling","ai agent class","openai sdk","anthropic sdk","google gemini sdk","workers-ai-provider","ai streaming backend","multi-provider ai","ai sdk errors","AI_APICallError","AI_NoObjectGeneratedError","streamText fails","worker startup limit ai"]}
license	MIT

AI SDK Core

Production-ready backend AI with Vercel AI SDK v5.

Last Updated: 2025-11-21

Table of Contents

1. Quick Start
2. Core Functions
3. Provider Setup & Configuration
4. Tool Calling & Agents
5. Critical v4→v5 Migration
6. Top 12 Errors & Solutions
7. Production Best Practices
8. When to Load References
9. When to Use This Skill
10. Dependencies & Versions
11. Links to Official Documentation
12. Templates & References

---

Quick Start (5 Minutes)

Installation

bun add ai @ai-sdk/openai @ai-sdk/anthropic @ai-sdk/google workers-ai-provider zod  # preferred
# or: npm install ai @ai-sdk/openai @ai-sdk/anthropic @ai-sdk/google workers-ai-provider zod

Environment Variables

# .env
OPENAI_API_KEY=sk-...
ANTHROPIC_API_KEY=sk-ant-...
GOOGLE_GENERATIVE_AI_API_KEY=...

First Example: Generate Text

import { generateText } from 'ai';
import { openai } from '@ai-sdk/openai';

const result = await generateText({
  model: openai('gpt-4-turbo'),
  prompt: 'What is TypeScript?',
});

console.log(result.text);

First Example: Streaming Chat

import { streamText } from 'ai';
import { anthropic } from '@ai-sdk/anthropic';

const stream = streamText({
  model: anthropic('claude-sonnet-4-5-20250929'),
  messages: [
    { role: 'user', content: 'Tell me a story' },
  ],
});

for await (const chunk of stream.textStream) {
  process.stdout.write(chunk);
}

First Example: Structured Output

import { generateObject } from 'ai';
import { openai } from '@ai-sdk/openai';
import { z } from 'zod';

const result = await generateObject({
  model: openai('gpt-4'),
  schema: z.object({
    name: z.string(),
    age: z.number(),
    skills: z.array(z.string()),
  }),
  prompt: 'Generate a person profile for a software engineer',
});

console.log(result.object);
// { name: "Alice", age: 28, skills: ["TypeScript", "React"] }

---

Core Functions

Load references/core-functions.md for complete API reference of all 4 core functions.

Quick Overview

AI SDK v5 provides 4 core functions:

Function	Output	Streaming	Use Case
generateText()	Text	No	Batch processing, simple completions
streamText()	Text	Yes	Chat UIs, long responses
generateObject()	Structured	No	Data extraction, JSON generation
streamObject()	Structured	Yes	Real-time forms, progressive UIs

Basic Example

import { generateText } from 'ai';
import { openai } from '@ai-sdk/openai';

const result = await generateText({
  model: openai('gpt-4-turbo'),
  prompt: 'Explain quantum computing',
});

console.log(result.text);

→ Load references/core-functions.md for: Complete signatures, tool usage patterns, error handling, streaming examples, comparison table

---

Provider Setup & Configuration

Load references/provider-setup.md for complete setup instructions for all providers.

Quick Overview

AI SDK v5 supports 4 major providers:

Provider	Environment Variable	Latest Models
OpenAI	OPENAI_API_KEY	GPT-5, GPT-4 Turbo
Anthropic	ANTHROPIC_API_KEY	Claude Sonnet 4.5, Opus 4
Google	GOOGLE_GENERATIVE_AI_API_KEY	Gemini 2.5 Pro/Flash
Cloudflare	Workers AI binding	Llama 3.1, Qwen 2.5

Basic Setup

import { openai } from '@ai-sdk/openai';
import { generateText } from 'ai';

// API key from environment
const result = await generateText({
  model: openai('gpt-4-turbo'),
  prompt: 'Hello',
});

→ Load references/provider-setup.md for: Complete API configuration, rate limiting, error handling, Cloudflare Workers optimization, model selection guides

---

Tool Calling & Agents

Load references/tools-and-agents.md for complete tool and agent documentation.

Quick Overview

Tools allow models to call external functions. Agents manage multi-step workflows.

v5 Tool Changes:

• parameters → inputSchema (Zod schema)
• Tool properties: args → input, result → output
• maxSteps → stopWhen(stepCountIs(n))

Basic Tool Example

import { generateText, tool } from 'ai';
import { z } from 'zod';

const result = await generateText({
  model: openai('gpt-4'),
  tools: {
    weather: tool({
      description: 'Get weather for a location',
      inputSchema: z.object({ location: z.string() }),
      execute: async ({ location }) => {
        return { temperature: 72, condition: 'sunny' };
      },
    }),
  },
  prompt: 'What is the weather in Tokyo?',
});

→ Load references/tools-and-agents.md for: Agent class usage, multi-step execution, dynamic tools, stop conditions

---

Critical v4→v5 Migration

Load references/v4-to-v5-migration.md for complete migration guide.

Key Breaking Changes

AI SDK v5 has 9 major breaking changes:

• maxTokens → maxOutputTokens
• parameters → inputSchema (Zod)
• maxSteps → stopWhen(stepCountIs(n))
• CoreMessage → ModelMessage
• Package reorganization (ai/rsc → @ai-sdk/rsc)

Automated Migration

bunx ai migrate  # Auto-migrates most changes

→ Load references/v4-to-v5-migration.md for: Complete breaking changes list, migration examples, checklist, official migration guide link

---

Top 12 Errors & Solutions

1. AI_APICallError

Cause: API request failed (network, auth, rate limit).

Solution:

import { AI_APICallError } from 'ai';

try {
  const result = await generateText({
    model: openai('gpt-4'),
    prompt: 'Hello',
  });
} catch (error) {
  if (error instanceof AI_APICallError) {
    console.error('API call failed:', error.message);
    console.error('Status code:', error.statusCode);
    console.error('Response:', error.responseBody);

    // Check common causes
    if (error.statusCode === 401) {
      // Invalid API key
    } else if (error.statusCode === 429) {
      // Rate limit - implement backoff
    } else if (error.statusCode >= 500) {
      // Provider issue - retry
    }
  }
}

Prevention:

• Validate API keys at startup
• Implement retry logic with exponential backoff
• Monitor rate limits
• Handle network errors gracefully

---

2. AI_NoObjectGeneratedError

Cause: Model didn't generate valid object matching schema.

Solution:

import { AI_NoObjectGeneratedError } from 'ai';

try {
  const result = await generateObject({
    model: openai('gpt-4'),
    schema: z.object({ /* complex schema */ }),
    prompt: 'Generate data',
  });
} catch (error) {
  if (error instanceof AI_NoObjectGeneratedError) {
    console.error('No valid object generated');

    // Solutions:
    // 1. Simplify schema
    // 2. Add more context to prompt
    // 3. Provide examples in prompt
    // 4. Try different model (gpt-4 better than gpt-3.5 for complex objects)
  }
}

Prevention:

• Start with simple schemas, add complexity incrementally
• Include examples in prompt: "Generate a person like: { name: 'Alice', age: 30 }"
• Use GPT-4 for complex structured output
• Test schemas with sample data first

---

3. Worker Startup Limit (270ms+)

Cause: AI SDK v5 + Zod initialization overhead in Cloudflare Workers exceeds startup limits.

Solution:

// BAD: Top-level imports cause startup overhead
import { createWorkersAI } from 'workers-ai-provider';
import { complexSchema } from './schemas';

const workersai = createWorkersAI({ binding: env.AI });

// GOOD: Lazy initialization inside handler
export default {
  async fetch(request, env) {
    const { createWorkersAI } = await import('workers-ai-provider');
    const workersai = createWorkersAI({ binding: env.AI });

    // Use workersai here
  }
}

Prevention:

• Move AI SDK imports inside route handlers
• Minimize top-level Zod schemas
• Monitor Worker startup time (must be <400ms)
• Use Wrangler's startup time reporting

GitHub Issue: Search for "Workers startup limit" in Vercel AI SDK issues

---

→ Load references/error-catalog.md for errors #4-#12 with complete solutions.

Remaining 9 errors: 4. streamText Fails Silently (RESOLVED in v4.1.22) 5. AI_LoadAPIKeyError 6. AI_InvalidArgumentError 7. AI_NoContentGeneratedError 8. AI_TypeValidationError 9. AI_RetryError 10. Rate Limiting Errors 11. TypeScript Performance with Zod 12. Invalid JSON Response (Provider-Specific)

For complete error catalog: See complete error reference at https://ai-sdk.dev/docs/reference/ai-sdk-errors

---

Production Best Practices

Load references/production-guide.md for complete production deployment guide.

Key Categories

1. Performance: Streaming patterns, token limits, provider caching, Zod optimization
2. Error Handling: try-catch patterns, retry logic, proper logging
3. Cost Optimization: Model selection, token limits, response caching
4. Cloudflare Workers: Lazy imports, startup monitoring, streaming responses
5. Next.js/Vercel: Server Actions, Server Components, loading states

Quick Example

// Use streaming for user-facing responses
const stream = streamText({
  model: openai('gpt-4'),
  prompt: 'Long essay',
  maxOutputTokens: 500,
  maxRetries: 3,
});

return stream.toDataStreamResponse();

→ Load references/production-guide.md for: Platform-specific patterns, deployment checklists, optimization strategies

---

When to Load References

Load references/core-functions.md when:

• User needs complete API documentation for generateText, streamText, generateObject, or streamObject
• Questions about function signatures, parameters, or return types
• Need detailed tool usage patterns or streaming examples
• Troubleshooting function-specific errors

Load references/provider-setup.md when:

• Setting up OpenAI, Anthropic, Google, or Cloudflare Workers AI
• Configuring API keys or environment variables
• Troubleshooting provider-specific errors (rate limits, authentication)
• Questions about model selection or best practices for each provider
• Cloudflare Workers startup optimization needed

Load references/tools-and-agents.md when:

• Implementing tool calling or agent workflows
• Questions about Agent class vs raw generateText
• Setting up multi-step execution with stopWhen
• Dynamic tools or complex agentic patterns

Load references/v4-to-v5-migration.md when:

• Migrating existing v4 codebase to v5
• Questions about breaking changes
• Need migration examples or automated migration tool
• Troubleshooting migration-related errors

Load references/error-catalog.md when:

• User encounters any of the 12 common errors (beyond top 3 shown inline)
• Need complete error solutions with code examples
• Troubleshooting production errors
• Questions about error prevention strategies

Load references/production-guide.md when:

• Deploying to production (any platform)
• Performance optimization needed
• Cost optimization questions
• Platform-specific patterns (Cloudflare Workers, Next.js/Vercel)
• Error handling or logging strategies

---

When to Use This Skill

Use ai-sdk-core when:

• Building backend AI features (server-side text generation)
• Implementing server-side text generation (Node.js, Workers, Next.js)
• Creating structured AI outputs (JSON, forms, data extraction)
• Building AI agents with tools (multi-step workflows)
• Integrating multiple AI providers (OpenAI, Anthropic, Google, Cloudflare)
• Migrating from AI SDK v4 to v5
• Encountering AI SDK errors (AI_APICallError, AI_NoObjectGeneratedError, etc.)
• Using AI in Cloudflare Workers (with workers-ai-provider)
• Using AI in Next.js Server Components/Actions
• Need consistent API across different LLM providers

Don't use this skill when:

• Building React chat UIs (use ai-sdk-ui skill instead)
• Need frontend hooks like useChat (use ai-sdk-ui skill instead)
• Need advanced topics like embeddings or image generation (check official docs)
• Building native Cloudflare Workers AI apps without multi-provider (use cloudflare-workers-ai skill instead)
• Need Generative UI / RSC (see https://ai-sdk.dev/docs/ai-sdk-rsc)

---

Dependencies & Versions

{
  "dependencies": {
    "ai": "^5.0.116",
    "@ai-sdk/openai": "^2.0.88",
    "@ai-sdk/anthropic": "^2.0.56",
    "@ai-sdk/google": "^2.0.51",
    "workers-ai-provider": "^2.0.0",
    "zod": "^3.23.8"
  },
  "devDependencies": {
    "@types/node": "^24.10.1",
    "typescript": "^5.9.3"
  }
}

Version Notes:

• AI SDK v5.0.116+ (stable, latest as of December 2025)
• v6 is in beta - not covered in this skill
• Zod compatibility: This skill uses Zod 3.x, but AI SDK 5 officially supports both Zod 3.x and Zod 4.x (4.1.12 latest)
  • Zod 4 recommended for new projects (released August 2025)
  • Zod 4 has breaking changes: error APIs, .default() behavior, ZodError.errors removed
  • Some peer dependency warnings may occur with zod-to-json-schema when using Zod 4
  • See https://zod.dev/v4/changelog for migration guide
• Provider packages at 2.0+ for v5 compatibility

Check Latest Versions:

npm view ai version
npm view @ai-sdk/openai version
npm view @ai-sdk/anthropic version
npm view @ai-sdk/google version
npm view workers-ai-provider version
npm view zod version  # Check for Zod 4.x updates

---

Links to Official Documentation

Core Documentation

• AI SDK Introduction: https://ai-sdk.dev/docs/introduction
• AI SDK Core Overview: https://ai-sdk.dev/docs/ai-sdk-core/overview
• Generating Text: https://ai-sdk.dev/docs/ai-sdk-core/generating-text
• Generating Structured Data: https://ai-sdk.dev/docs/ai-sdk-core/generating-structured-data
• Tools and Tool Calling: https://ai-sdk.dev/docs/ai-sdk-core/tools-and-tool-calling
• Agents Overview: https://ai-sdk.dev/docs/agents/overview
• Foundations: https://ai-sdk.dev/docs/foundations/overview

Advanced Topics (Not Replicated in This Skill)

• Embeddings: https://ai-sdk.dev/docs/ai-sdk-core/embeddings
• Image Generation: https://ai-sdk.dev/docs/ai-sdk-core/generating-images
• Transcription: https://ai-sdk.dev/docs/ai-sdk-core/generating-transcriptions
• Speech: https://ai-sdk.dev/docs/ai-sdk-core/generating-speech
• MCP Tools: https://ai-sdk.dev/docs/ai-sdk-core/mcp-tools
• Telemetry: https://ai-sdk.dev/docs/ai-sdk-core/telemetry
• Generative UI: https://ai-sdk.dev/docs/ai-sdk-rsc

Migration & Troubleshooting

• v4→v5 Migration Guide: https://ai-sdk.dev/docs/migration-guides/migration-guide-5-0
• All Error Types (28 total): https://ai-sdk.dev/docs/reference/ai-sdk-errors
• Troubleshooting Guide: https://ai-sdk.dev/docs/troubleshooting

Provider Documentation

• OpenAI Provider: https://ai-sdk.dev/providers/ai-sdk-providers/openai
• Anthropic Provider: https://ai-sdk.dev/providers/ai-sdk-providers/anthropic
• Google Provider: https://ai-sdk.dev/providers/ai-sdk-providers/google
• All Providers (25+): https://ai-sdk.dev/providers/overview
• Community Providers: https://ai-sdk.dev/providers/community-providers

Cloudflare Integration

• Workers AI Provider (Community): https://ai-sdk.dev/providers/community-providers/cloudflare-workers-ai
• Cloudflare Workers AI Docs: https://developers.cloudflare.com/workers-ai/
• workers-ai-provider GitHub: https://github.com/cloudflare/ai/tree/main/packages/workers-ai-provider
• Cloudflare AI SDK Configuration: https://developers.cloudflare.com/workers-ai/configuration/ai-sdk/

Vercel / Next.js Integration

• Vercel AI SDK 5.0 Blog: https://vercel.com/blog/ai-sdk-5
• Next.js App Router Integration: https://ai-sdk.dev/docs/getting-started/nextjs-app-router
• Next.js Pages Router Integration: https://ai-sdk.dev/docs/getting-started/nextjs-pages-router
• Vercel Functions: https://vercel.com/docs/functions
• Vercel Streaming: https://vercel.com/docs/functions/streaming

GitHub & Community

• GitHub Repository: https://github.com/vercel/ai
• GitHub Issues: https://github.com/vercel/ai/issues
• Discord Community: https://discord.gg/vercel

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Templates & References

This skill includes:

• 13 Templates: Ready-to-use code examples in templates/
• 5 Reference Docs: Detailed guides in references/
• 1 Script: Version checker in scripts/

All files are optimized for copy-paste into your project.

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Last Updated: 2025-12-22 Skill Version: 1.1.0 AI SDK Version: 5.0.116+