mastra-ai/mastra · error

toAISdkFormat() has been deprecated. Please use toAISdkStrea

Error message

toAISdkFormat() has been deprecated. Please use toAISdkStream() instead.

Migration:
  import { toAISdkFormat } from "@mastra/ai-sdk";
  // Change to:
  import { toAISdkStream } from "@mastra/ai-sdk";

The function signature remains the same.

What it means

toAISdkFormat was removed and replaced by toAISdkStream in @mastra/ai-sdk. The old export now always throws this deprecation error with migration instructions; the function signature is unchanged, so only the name needs updating.

Source

Thrown at client-sdks/ai-sdk/src/to-ai-sdk-format.ts:16

/**
 * @deprecated Use `toAISdkStream` instead. This function has been renamed for clarity.
 *
 * @example
 * ```typescript
 * // Old (deprecated):
 * import { toAISdkFormat } from '@mastra/ai-sdk';
 * const stream = toAISdkFormat(agentStream, { from: 'agent' });
 *
 * // New:
 * import { toAISdkStream } from '@mastra/ai-sdk';
 * const stream = toAISdkStream(agentStream, { from: 'agent' });
 * ```
 */
export function toAISdkFormat(): never {
  throw new Error(
    'toAISdkFormat() has been deprecated. Please use toAISdkStream() instead.\n\n' +
      'Migration:\n' +
      '  import { toAISdkFormat } from "@mastra/ai-sdk";\n' +
      '  // Change to:\n' +
      '  import { toAISdkStream } from "@mastra/ai-sdk";\n\n' +
      'The function signature remains the same.',
  );
}

View on GitHub (pinned to 75dd419e61)

Solutions

1. Rename the call from toAISdkFormat to toAISdkStream; arguments stay the same.
2. Update the import to: import { toAISdkStream } from '@mastra/ai-sdk'.
3. Search the codebase for toAISdkFormat to catch all call sites.
4. Follow the migration note in the @mastra/ai-sdk changelog for the release you upgraded to.

Example fix

// before
import { toAISdkFormat } from '@mastra/ai-sdk';
const uiStream = toAISdkFormat(agentStream, { from: 'agent' });
// after
import { toAISdkStream } from '@mastra/ai-sdk';
const uiStream = toAISdkStream(agentStream, { from: 'agent' });

import * as aiSdk from '@mastra/ai-sdk';
if (!('toAISdkStream' in aiSdk)) throw new Error('Upgrade @mastra/ai-sdk');

let uiStream;
try {
  uiStream = toAISdkStream(agentStream, { from: 'agent' });
} catch (e) {
  if (e instanceof Error && e.message.includes('deprecated')) {
    uiStream = toAISdkStream(agentStream, { from: 'agent' });
  } else throw e;
}

When it happens

Trigger: Calling toAISdkFormat(agentStream, { from: 'agent' }) anywhere in app code after upgrading to a @mastra/ai-sdk version where the export was deprecated; importing the old name from autocomplete or older docs/snippets.

Common situations: Upgrading @mastra/ai-sdk without following the codemod/changelog; copy-pasted tutorial code written against the old API; TypeScript types don't flag it because the export still exists (typed as never).

Related errors

• The 'processors' option in Memory is deprecated and has been
• MastraFactory: 'sandbox' is now a callback, not an options o
• The workingMemory.use option has been removed. Working memor
• The threads.generateTitle option has been moved. Use the top
• The "elicitation" key is now nested under "mcp.elicitation"

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/a0e638711bb33ad2. Report an issue: GitHub.