# Use ACP-compatible harnesses with the AI SDK harness layer

Source: [Vercel](https://vercel.com/changelog/use-acp-compatible-harnesses-with-the-ai-sdk-harness-layer)  
Feed7 permalink: https://feed7.dev/p/use-acp-compatible-harnesses-with-the-ai-sdk-harness-layer-105d5cg  
Published: 2026-08-13T00:00:00.000Z  
Trust: Official Source (official_source)

## Why Included

A new ACP meta-adapter lets HarnessAgent run compatible runtimes that lack dedicated integrations. Keep direct Claude Code and Codex adapters where tighter behavior matters.

## Source Summary

The new **@ai-sdk/harness-acp** package adapts the Agent Client Protocol rather than one runtime. Builders pass an ACP-compatible package to **createACP**, map the harness basics, and use the result with HarnessAgent.

## Practical Implication

Use the meta-adapter to connect a compatible harness that has no native AI SDK integration. For **Claude Code and Codex**, Vercel recommends their dedicated adapters because they can expose runtime behavior more precisely.

## Agent-Ready Context

The new **@ai-sdk/harness-acp** package adapts the Agent Client Protocol rather than one runtime. Builders pass an ACP-compatible package to **createACP**, map the harness basics, and use the result with HarnessAgent.

Use the meta-adapter to connect a compatible harness that has no native AI SDK integration. For **Claude Code and Codex**, Vercel recommends their dedicated adapters because they can expose runtime behavior more precisely.

ACP is not universal, and its abstraction may limit or alter access to a harness’s internals. Treat protocol compatibility as a portability option, then test permissions, events, and runtime-specific behavior before replacing a direct adapter.

## Connected Context

Feed7 judgment across 461 accumulated Signals:

The ACP meta-adapter broadens HarnessAgent from a set of native integrations into a portability layer for compatible runtimes. It narrows the abstraction’s role, however: protocol compatibility can reduce integration work, but dedicated adapters remain preferable when precise runtime behavior matters.

- [Grok Build is now available in the AI SDK harness layer](https://feed7.dev/p/grok-build-harness-adapter-0edn2xt) — The Grok Build integration demonstrates how an ACP-based adapter can add a runtime behind the common HarnessAgent interface while retaining the need to test runtime-specific behavior.
- [The Prime Intellect Stack — Will Brown, Prime Intellect](https://feed7.dev/p/the-prime-intellect-stack-will-brown-prime-intellect-1dc0rrp) — Prime Intellect’s endpoint interceptor pursues the same no-rewrite interoperability goal for existing harnesses, but applies it to participation in evaluation, data-generation, and RL environments rather than application orchestration.

## Context Map

- Layer: tools
- Domains: coding
- Topics: coding-agents, agent-sdks, harness-engineering

## Uncertainty

- ACP is not universal, and its abstraction may limit or alter access to a harness’s internals. Treat protocol compatibility as a portability option, then test permissions, events, and runtime-specific behavior before replacing a direct adapter.

## Agent Instruction

Use this item as source-backed context. Do not invent claims beyond the linked source. If this item conflicts with another source, call out the conflict.