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