docs: add comprehensive READMEs for all service packages

Agent-Logs-Url: https://github.com/objectstack-ai/framework/sessions/0ea8718e-c180-4863-8bbb-e522375ff695

Co-authored-by: xuyushun441-sys <255036401+xuyushun441-sys@users.noreply.github.com>

Author: Claude

packages/services/service-ai/README.md

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+# @objectstack/service-ai
+
+AI Service for ObjectStack — implements `IAIService` with LLM adapter layer, conversation management, tool registry, and REST/SSE routes.
+
+## Features
+
+- **Multi-Provider LLM Support**: Supports OpenAI, Anthropic, Google, and custom gateway providers via Vercel AI SDK
+- **Conversation Management**: Track and manage AI conversations with full history
+- **Tool Registry**: Register and execute tools that AI agents can call
+- **Streaming Support**: Real-time streaming responses via Server-Sent Events (SSE)
+- **REST API**: Auto-generated endpoints for AI operations
+- **Type-Safe**: Full TypeScript support with type inference
+
+## Installation
+
+```bash
+pnpm add @objectstack/service-ai
+```
+
+### Peer Dependencies
+
+Install the LLM provider(s) you need:
+
+```bash
+# OpenAI
+pnpm add @ai-sdk/openai
+
+# Anthropic (Claude)
+pnpm add @ai-sdk/anthropic
+
+# Google (Gemini)
+pnpm add @ai-sdk/google
+
+# Custom Gateway
+pnpm add @ai-sdk/gateway
+```
+
+All peer dependencies are optional — install only what you need.
+
+## Basic Usage
+
+```typescript
+import { defineStack } from '@objectstack/spec';
+import { ServiceAI } from '@objectstack/service-ai';
+import { openai } from '@ai-sdk/openai';
+
+const stack = defineStack({
+  services: [
+    ServiceAI.configure({
+      models: {
+        default: openai('gpt-4'),
+        fast: openai('gpt-3.5-turbo'),
+      },
+    }),
+  ],
+});
+```
+
+## Configuration
+
+```typescript
+interface AIServiceConfig {
+  /** Map of model IDs to AI SDK model instances */
+  models: Record<string, LanguageModel>;
+
+  /** Default model to use when not specified */
+  defaultModel?: string;
+
+  /** Maximum conversation history length */
+  maxHistoryLength?: number;
+
+  /** Enable streaming responses (default: true) */
+  enableStreaming?: boolean;
+}
+```
+
+## Service API
+
+The `IAIService` interface provides:
+
+### Conversation Management
+
+```typescript
+// Get AI service from kernel
+const ai = kernel.getService<IAIService>('ai');
+
+// Create a new conversation
+const conversation = await ai.createConversation({
+  model: 'default',
+  systemPrompt: 'You are a helpful assistant.',
+});
+
+// Send a message
+const response = await ai.sendMessage({
+  conversationId: conversation.id,
+  message: 'What is ObjectStack?',
+});
+
+// Stream a message
+const stream = await ai.streamMessage({
+  conversationId: conversation.id,
+  message: 'Explain in detail...',
+});
+
+for await (const chunk of stream) {
+  process.stdout.write(chunk.text);
+}
+```
+
+### Tool Registry
+
+```typescript
+// Register a tool
+ai.registerTool({
+  name: 'get_weather',
+  description: 'Get current weather for a location',
+  parameters: {
+    type: 'object',
+    properties: {
+      location: { type: 'string', description: 'City name' },
+    },
+    required: ['location'],
+  },
+  execute: async ({ location }) => {
+    // Your tool implementation
+    return { temperature: 72, condition: 'sunny' };
+  },
+});
+
+// Tools are automatically available to AI agents
+const response = await ai.sendMessage({
+  conversationId: conversation.id,
+  message: 'What is the weather in San Francisco?',
+});
+```
+
+## REST API Endpoints
+
+When used with `@objectstack/rest`, the following endpoints are auto-generated:
+
+```
+POST   /api/v1/ai/conversations          # Create conversation
+GET    /api/v1/ai/conversations/:id      # Get conversation
+POST   /api/v1/ai/conversations/:id/messages  # Send message
+GET    /api/v1/ai/conversations/:id/stream    # Stream response (SSE)
+GET    /api/v1/ai/tools                  # List available tools
+POST   /api/v1/ai/tools/:name/execute    # Execute a tool
+```
+
+## Multi-Model Configuration
+
+```typescript
+import { openai } from '@ai-sdk/openai';
+import { anthropic } from '@ai-sdk/anthropic';
+import { google } from '@ai-sdk/google';
+
+const stack = defineStack({
+  services: [
+    ServiceAI.configure({
+      models: {
+        // Fast model for simple tasks
+        fast: openai('gpt-3.5-turbo'),
+
+        // Default model for general use
+        default: openai('gpt-4'),
+
+        // Advanced reasoning
+        reasoning: openai('gpt-4-turbo'),
+
+        // Anthropic Claude
+        claude: anthropic('claude-3-opus-20240229'),
+
+        // Google Gemini
+        gemini: google('gemini-pro'),
+      },
+      defaultModel: 'default',
+    }),
+  ],
+});
+```
+
+## Advanced Features
+
+### Custom System Prompts
+
+```typescript
+const conversation = await ai.createConversation({
+  model: 'default',
+  systemPrompt: `You are an expert in ObjectStack.
+    Answer questions about the framework accurately and concisely.
+    Always provide code examples when relevant.`,
+});
+```
+
+### Conversation History
+
+```typescript
+// Get full conversation history
+const history = await ai.getConversationHistory(conversationId);
+
+// Clear conversation history
+await ai.clearConversation(conversationId);
+
+// Delete conversation
+await ai.deleteConversation(conversationId);
+```
+
+### Error Handling
+
+```typescript
+try {
+  const response = await ai.sendMessage({
+    conversationId: conversation.id,
+    message: 'Hello',
+  });
+} catch (error) {
+  if (error.code === 'RATE_LIMIT_EXCEEDED') {
+    // Handle rate limiting
+  } else if (error.code === 'MODEL_NOT_FOUND') {
+    // Handle missing model
+  }
+}
+```
+
+## Integration with ObjectStack Agents
+
+The AI service integrates with the `@objectstack/spec/ai` agent protocol:
+
+```typescript
+import { defineAgent } from '@objectstack/spec';
+
+const myAgent = defineAgent({
+  name: 'code_assistant',
+  model: 'default',
+  systemPrompt: 'You help write ObjectStack code.',
+  tools: ['create_object', 'create_field', 'create_view'],
+});
+
+// Agent automatically uses the AI service
+const result = await myAgent.execute({
+  input: 'Create a contact object with name and email fields',
+});
+```
+
+## Architecture
+
+The service follows a layered architecture:
+
+1. **Adapter Layer**: Abstracts different LLM providers (OpenAI, Anthropic, Google)
+2. **Conversation Manager**: Handles conversation state and history
+3. **Tool Registry**: Manages tool registration and execution
+4. **REST Routes**: Auto-generated HTTP endpoints
+5. **SSE Streaming**: Real-time streaming support
+
+## Contract Implementation
+
+Implements `IAIService` from `@objectstack/spec/contracts`:
+
+```typescript
+interface IAIService {
+  createConversation(options: ConversationOptions): Promise<Conversation>;
+  sendMessage(options: MessageOptions): Promise<Message>;
+  streamMessage(options: MessageOptions): AsyncIterable<MessageChunk>;
+  registerTool(tool: AITool): void;
+  getConversationHistory(conversationId: string): Promise<Message[]>;
+  deleteConversation(conversationId: string): Promise<void>;
+}
+```
+
+## Performance Considerations
+
+- **Streaming**: Use streaming for long responses to improve perceived performance
+- **Model Selection**: Choose appropriate models based on task complexity
+- **Conversation History**: Limit history length to control token usage
+- **Caching**: Provider-level caching is handled automatically
+
+## Best Practices
+
+1. **Model Selection**: Use fast models for simple tasks, advanced models for complex reasoning
+2. **System Prompts**: Provide clear, specific instructions in system prompts
+3. **Tool Design**: Keep tools focused and well-documented
+4. **Error Handling**: Always handle rate limits and API errors gracefully
+5. **Streaming**: Use streaming for better UX on long-running queries
+
+## License
+
+Apache-2.0
+
+## See Also
+
+- [Vercel AI SDK Documentation](https://sdk.vercel.ai/docs)
+- [@objectstack/spec/ai Protocol](../../spec/src/ai/)
+- [AI Agent Guide](/content/docs/guides/ai/)