Vercel AI Updates: June 20, 2026

1. AI SDK Workflow Now Rejects System Messages in Prompts by Default

Vercel. The AI SDK shipped @ai-sdk/workflow@1.0.0-beta.101, changing WorkflowAgent to reject system messages passed through prompt or messages by default. The behavior now matches generateText and streamText, aligning the workflow agent with the rest of the SDK. Developers who depend on the previous handling can restore it by setting allowSystemInMessages: true. Source

2. AI SDK TUI Adds Sandbox Option and Broader Agent Support

Vercel. The AI SDK released @ai-sdk/tui@1.0.0-beta.18, expanding runAgentTUI to accept any AI SDK Agent generic combination rather than a narrower set. The release also adds a sandbox option to runAgentTUI that is forwarded to the agent’s stream calls so tool execution can run inside a sandbox. The changes broaden compatibility and give terminal-based agents sandboxed tool execution. Source

3. AI SDK Defaults OpenAI Reasoning Summaries to Detailed

Vercel. The AI SDK shipped @ai-sdk/openai@4.0.0-beta.75, changing the default so OpenAI Responses reasoning summaries are set to detailed when reasoning effort is enabled. The update gives developers fuller reasoning output by default rather than requiring them to opt in. Source