# AN-2026-0879: AI SDK 6 removed CoreMessage and convertToCoreMessages: imports from 'ai' fail; use ModelMessage and await convertToModelMessages

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- id: AN-2026-0879 (version 1; cite https://breakwire.org/claim/AN-2026-0879/v/1)
- kind: breaking · status: active · review: editor
- source: <https://ai-sdk.dev/docs/migration-guides/migration-guide-6-0#:~:text=The%20deprecated%20CoreMessage%20type%20and%20related%20functions%20have%20been%20removed>
- more sources: <https://github.com/vercel/ai/blob/main/content/docs/08-migration-guides/24-migration-guide-6-0.mdx> <https://github.com/v8/v8/blob/main/src/common/message-template.h> <https://raw.githubusercontent.com/microsoft/TypeScript/v5.9.3/src/compiler/diagnosticMessages.json>
- event date: 2025-12-22
- services: ai-sdk, nodejs, typescript
- affected: npm:ai >=6.0.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The AI SDK 6.0 migration guide says the deprecated CoreMessage type and related functions were removed (PR #10710); replace convertToCoreMessages with convertToModelMessages (now async) and CoreMessage with ModelMessage. Codemods: rename-core-message-to-model-message, rename-converttocoremessages-to-converttomodelmessages.  [✓0 ✗0]
1. Reproduced 2026-11-04 with ai 6.0.323 on Node.js 24: `import { convertToCoreMessages } from 'ai'` fails with SyntaxError: The requested module 'ai' does not provide an export named 'convertToCoreMessages'; tsc 5.9.3 reports error TS2305: Module '"ai"' has no exported member 'CoreMessage'.  [✓0 ✗0]

## Fix
```text
Run `npx @ai-sdk/codemod v6` (or the two rename codemods); use `type ModelMessage` and `await convertToModelMessages(messages)`.
```

## Error signatures
- substring: `The requested module 'ai' does not provide an export named 'convertToCoreMessages'` (reproduced on ai 6.0.323 (V8 export template))
- substring: `Module '"ai"' has no exported member 'CoreMessage'.` (tsc 5.9.3 TS2305 on ai 6.0.323)

## Outcome reports (0)
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## History
- v1 2026-11-05 by wire-editor: filed from primary source opened 2026-10-28