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Vercel AI SDK Adds Fable 5.1 Support and xAI File Interface Enhancements

The Vercel AI SDK now supports Fable 5.1 through its Anthropic package and introduces new file management capabilities for xAI, including streaming uploads and metadata retrieval.

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Source · Sep 2, 2026, 3:10 AM · On Illumora · Sep 2, 2026, 3:13 AM

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Read the source →Vercel AI SDK Changelog — Release @ai-sdk/anthropic@2.0.101 · vercel/ai
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The Vercel AI SDK has updated its @ai-sdk/anthropic package to include support for Fable 5.1. This change was released on September 2.

Additionally, the @ai-sdk/xai package received enhancements to its file interface, implementing functions for file metadata, streaming downloads, and file deletion. These updates, released on September 1, also introduce support for expiresAfter upload Time-To-Live (TTL) settings and streaming uploads.

Key Points

  • The @ai-sdk/anthropic@2.0.101 package now supports Fable 5.1.
  • This update for Anthropic integration was released on September 2.
  • The @ai-sdk/xai@4.0.52 package implements getFileMetadata, downloadFile (streaming), and deleteFile for the xAI files interface.
  • The xAI package supports expiresAfter upload TTLs, ranging from 3600 to 2592000 seconds.
  • Streaming uploads are now supported via { type: 'stream' } data in the xAI package.
  • Upload results from xAI operations expose byteSize, createdAt, and expiresAt.
  • The xAI file operations thread abortSignal and headers through all calls.

Context

According to the Vercel AI SDK changelog, the @ai-sdk/anthropic package's update specifically adds support for Fable 5.1. The @ai-sdk/xai package's enhancements include new file management functionalities such as retrieving file metadata, streaming file downloads, and deleting files. It also introduces expiresAfter upload TTLs, which are integer values between 3600 and 2592000 seconds, emitted before the file part as required by xAI. Streaming uploads are facilitated through a { type: 'stream' } data mechanism, and upload results now provide byteSize, createdAt, and expiresAt information. The changelog also notes that abortSignal and headers are threaded through all file operations, and blank or dot-segment file IDs are rejected or encoded to prevent request path retargeting.

Why It Matters

These updates provide developers using the Vercel AI SDK with expanded model compatibility and enhanced file handling capabilities for specific AI services. The addition of Fable 5.1 support allows integration with a newer model, while the xAI file interface improvements offer more granular control over file management, including streaming and metadata access, which can impact application design and data workflows.

What To Do

  • Review the Vercel AI SDK documentation for the @ai-sdk/anthropic package to understand Fable 5.1 integration details.
  • Examine the @ai-sdk/xai package documentation for the new getFileMetadata, downloadFile, and deleteFile functions.
  • Test the expiresAfter upload TTL functionality in the xAI package, noting the supported time range.
  • Investigate the implementation of streaming uploads via { type: 'stream' } data for xAI file operations.