Vercel AI Updates: August 15, 2026

1. Grok Build Joins the AI SDK Harness Layer

Vercel. Vercel added a @ai-sdk/harness-grok-build adapter that lets developers run xAI’s Grok Build coding-agent runtime through the same HarnessAgent interface used by other supported harnesses. The addition brings the harness layer’s supported list to Claude Code, Codex, Deep Agents, Grok Build, OpenCode, and Pi, with more planned. Because the interface is standardized, developers can swap Grok Build in and out of applications without rewriting code. Source

2. AI SDK Harness Layer Supports Any ACP-Compatible Harness

Vercel. Vercel released @ai-sdk/harness-acp, a meta adapter that lets the AI SDK harness layer work with any harness that ships an Agent Client Protocol (ACP) compatible package. Rather than requiring a dedicated adapter per runtime, developers can wrap an ACP harness by passing its package to createACP and configuring basic mapping. Vercel recommends using direct adapters such as @ai-sdk/harness-claude-code when available for tighter integration, and reserving the ACP adapter for harnesses that lack one. Source