What shipped? Vercel released @ai-sdk/harness-cline, the official Cline adapter for the AI SDK harness layer, on August 18, 2026.
What changed? The AI SDK harness layer (launched earlier) lets you run different coding-agent runtimes through one unified HarnessAgent interface. Cline is now the third supported runtime alongside the launch partners. Built in collaboration with the Cline team, the adapter drops in as a dependency swap — switch from another harness to Cline without changing your application code.
Why a builder cares. Cline is one of the most popular open-source coding agents. If you're building agentic workflows on Vercel, you now get Cline's tool-use loop through the same harness API as everything else. Less vendor lock-in per agent runtime, less integration surface to maintain.