[prototype] language model v2 spec

[lgrammel]

Why

• provider-specific message and message part extensions
• provider-specific response / finish metadata
• support for various data parts, both as input and output
• eliminate differences between regular, object-json, object-tool modes
• return ids & response model for telemetry
• return raw response information to help with debugging
• support models that provide sources (for RAG)

Tasks

• draft language model v2 spec
• prototypes
  • Anthropic: prompt caching
  • OpenAI: custom role names
  • google gen ai: pdf support
  • google vertex: sources
  • OpenAI: log response model & id
• regression check
  • streamobject tool
  • streamobject json
  • generateobject tool
  • generateobject json
• implementation
  • AI SDK
    • generateText
    • streamText
    • generateObject
    • streamObject
    • streamUI
  • Providers

[kdawgwilk]

I am probably missing something but couldn't you just add this field in a backwards compatible way to the LanguageModelV1 types since the property is optional?

[lgrammel]

Good point. My preference is to move to a cleaner language model, but considering the need to get prompt caching ready sooner rather than later I'll see if that's an option.