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](#quick-start-5-minutes)
2. [Core Functions](#core-functions)
3. [Provider Setup & Configuration](#provider-setup--configuration)
4. [Tool Calling & Agents](#tool-calling--agents)
5. [Critical v4→v5 Migration](#critical-v4v5-migration)
6. [Top 12 Errors & Solutions](#top-12-errors--solutions)
7. [Production Best Practices](#production-best-practices)
8. [When to Load References](#when-to-load-references)
9. [When to Use This Skill](#when-to-use-this-skill)
10. [Dependencies & Versions](#dependencies--versions)
11. [Links to Official Documentation](#links-to-official-documentation)
12. [Templates & References](#templates--references)

---

## Quick Start (5 Minutes)

### Installation

```bash
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

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

### First Example: Generate Text

```typescript
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

```typescript
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

```typescript
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

```typescript
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

```typescript
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

```typescript
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

```bash
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:**
```typescript
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:**
```typescript
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:**
```typescript
// 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

```typescript
// 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

```json
{
  "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:**
```bash
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

---

## 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.

---

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