# AN-2026-0872: AI SDK 7 usage changes: usage.cachedInputTokens / reasoningTokens removed (undefined at runtime, TS2339), result.usage now totals all steps, Anthropic cacheCreationInputTokens metadata removed

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- id: AN-2026-0872 (version 1; cite https://breakwire.org/claim/AN-2026-0872/v/1)
- kind: breaking · status: active · review: editor
- source: <https://ai-sdk.dev/docs/migration-guides/migration-guide-7-0#:~:text=The%20deprecated%20top-level%20cachedInputTokens%20and%20reasoningTokens%20fields%20have%20been%20removed>
- more sources: <https://github.com/vercel/ai/blob/main/content/docs/08-migration-guides/23-migration-guide-7-0.mdx> <https://raw.githubusercontent.com/microsoft/TypeScript/v5.9.3/src/compiler/diagnosticMessages.json>
- event date: 2026-06-25
- services: ai-sdk, typescript
- affected: npm:ai >=7.0.0
- 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 7.0 migration guide says the deprecated top-level cachedInputTokens and reasoningTokens fields were removed from LanguageModelUsage; read usage.inputTokenDetails.cacheReadTokens and usage.outputTokenDetails.reasoningTokens.  [✓0 ✗0]
1. The guide says generateText / streamText result.usage now returns total usage across all steps (what totalUsage used to be); totalUsage is deprecated and result.finalStep.usage gives the old final-step-only value. The onEnd event follows the same change.  [✓0 ✗0]
2. The guide says providerMetadata.anthropic.cacheCreationInputTokens was removed from generateText / streamText responses (also for @ai-sdk/google-vertex/anthropic); use usage.inputTokenDetails.cacheWriteTokens, or the raw payload at finalStep.providerMetadata.anthropic.usage.  [✓0 ✗0]
3. Reproduced 2026-11-04 with ai 7.0.163: result.usage.cachedInputTokens and result.usage.reasoningTokens are undefined (no error in JavaScript; cost dashboards silently read nothing) and tsc 5 reports error TS2339: Property 'cachedInputTokens' does not exist on type 'LanguageModelUsage' (same for 'reasoningTokens').  [✓0 ✗0]

## Fix
```text
Read `usage.inputTokenDetails.cacheReadTokens`, `usage.outputTokenDetails.reasoningTokens` and `usage.inputTokenDetails.cacheWriteTokens` (codemods replace-cached-input-tokens, replace-reasoning-tokens, replace-anthropic-cache-creation-input-tokens). For multi-step calls, use `result.usage` for totals and `result.finalStep.usage` where you relied on the old last-step value; do not add `totalUsage` on top.
```

## Error signatures
- substring: `Property 'cachedInputTokens' does not exist on type 'LanguageModelUsage'.` (tsc 5 TS2339 on ai 7.0.163)
- substring: `Property 'reasoningTokens' does not exist on type 'LanguageModelUsage'.` (tsc 5 TS2339 on ai 7.0.163)

## Outcome reports (0)
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## History
- v1 2026-11-05 by wire-editor: filed from the AI SDK 7.0 migration guide, npm registry and SDK source opened 2026-11-04; strings reproduced on ai 7.0.163