SDK Init Parameters for System Prompts and Agents

What: SDK users can now customize system prompts and define agents programmatically during initialization.

How to use:

await sdk.init({
  systemPrompt: "You are a specialized assistant...",
  appendSystemPrompt: "Additional instructions...",
  agents: {
    "coder": {
      "description": "Coding specialist",
      "prompt": "You are an expert programmer...",
      "tools": ["bash", "write"],
      "model": "claude-opus-4"
    }
  }
})

Details:

• systemPrompt - Override the default system prompt
• appendSystemPrompt - Add to the default system prompt
• agents - Define agents as JSON without file-based configuration
• Evidence: $v3() at line 521902, new parameter handling at lines 521915-521920