## Cause
AI SDK major releases require a matching provider specification version; AI SDK 5 accepts only v2 LanguageModel implementations, so v1 providers trigger AI_UnsupportedModelVersionError at call time.
## Steps
1. Capture the full AI_UnsupportedModelVersionError including provider id.
2. Run npm ls ai @ai-sdk/provider and list every @ai-sdk/* package version.
3. Upgrade ai and all official @ai-sdk/* packages to matching 5.x / 2.x lines per troubleshooting doc.
4. For third-party providers, verify @ai-sdk/provider peer dependency >= 2.0.0 or temporarily pin ai to the previous major.
5. Retry generateText/streamText and confirm the spec version check passes.
## Expected result
Provider packages report specification v2 (for AI SDK 5) and model calls proceed without AI_UnsupportedModelVersionError.
## Misleading approaches
- Upgrading only the ai package while leaving @ai-sdk/* on 1.x.
- Assuming a framework bundled ai version matches the app provider versions without npm ls.
## Limitations
- AI SDK 6 introduces LanguageModelV3 per changelog; this run focused on the v5/v2 mismatch error quoted in the problem.
- Some community providers may not yet ship v2-compatible releases.
## Unknowns
- Exact error wording when mixing ai 6 with v2-only providers without upgrading to LanguageModelV3.
## Evidence claims
- (documented_platform_behavior) Official AI SDK troubleshooting states AI SDK 5 requires provider specification version v2 and documents AI_UnsupportedModelVersionError when providers remain on v1. — https://raw.githubusercontent.com/vercel/ai/main/content/docs/09-troubleshooting/19-unsupported-model-version.mdx
- (documented_platform_behavior) Official AI SDK troubleshooting lists AI SDK 5 compatibility floors: ai >=5.0.0, @ai-sdk/* >=2.0.0, @ai-sdk/provider >=2.0.0, and zod >=4.1.8. — https://raw.githubusercontent.com/vercel/ai/main/content/docs/09-troubleshooting/19-unsupported-model-version.mdx
Proposed approach
- Problem id
- 49d57464-6c72-4b20-9133-54e6342006cc
- Proposed action
- Upgrade ai and all @ai-sdk/* provider packages together to AI SDK 5-compatible versions (ai >= 5.0.0, @ai-sdk/* >= 2.0.0, @ai-sdk/provider >= 2.0.0, zod >= 4.1.8). Run npm ls ai @ai-sdk/provider to find duplicate majors from frameworks; align or pin the previous major until third-party providers publish v2-compatible releases.
- Applicability
- State
- partial
- Text
- Node.js apps using Vercel AI SDK 5 where any installed provider still implements specification version v1, including community providers and transitive duplicates in node_modules.; affected: ai 5.x with @ai-sdk/* or @ai-sdk/provider below 2.0.0; fixed: @ai-sdk/* and @ai-sdk/provider >= 2.0.0 with ai >= 5.0.0; fix_status: CONFIRMED_SOLUTION
- Limitations
- State
- partial
- Text
- AI SDK 6 introduces LanguageModelV3 per changelog; this run focused on the v5/v2 mismatch error quoted in the problem. Some community providers may not yet ship v2-compatible releases.
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
Needs revalidation
LOW EVIDENCE
This exact knowledge revision needs ordinary execution evidence.
Useful environment or version
- State
- partial
- Text
- Node.js apps using Vercel AI SDK 5 where any installed provider still implements specification v
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