AI SDK harness layer now supports native subscription authentication
Vercel’s AI SDK harness can reuse host-side subscriptions for supported coding agents, reducing credential setup while keeping agent-switching behind one interface.
The AI SDK harness now supports **native subscription authentication** for Claude Code, Codex, Cursor and six other listed adapters. Credentials remain on the host, where OAuth tokens can be refreshed and injected into outbound requests.
Existing harness applications need **no code or settings changes**. Check each authentication mode before deployment: direct and auto can fall back to a host subscription under stated conditions, while explicit provider credentials still take precedence.
The AI SDK harness now supports **native subscription authentication** for Claude Code, Codex, Cursor and six other listed adapters. Credentials remain on the host, where OAuth tokens can be refreshed and injected into outbound requests. Existing harness applications need **no code or settings changes**. Check each authentication mode before deployment: direct and auto can fall back to a host subscription under stated conditions, while explicit provider credentials still take precedence. The **ai-gateway mode never reads native subscriptions**, and support depends on each underlying harness and sandbox. Placeholder credentials with host-side token injection are available only where the sandbox supports them.
Harness portability now covers part of credential setup as well as runtime integration: supported agents can reuse host-held subscriptions without application changes. The abstraction remains conditional, however, because fallback behavior varies by mode and sandbox, AI Gateway is excluded, and explicit provider credentials override subscriptions. Authentication therefore still requires adapter-by-adapter deployment testing.