Responses API

OpenAI released version 2.53.0 of its Python SDK, adding type definitions referencing a model called 'gpt-5.5' along with new tool name/namespace fields for the Responses API. OpenAI has not made any public announcement about a GPT-5.5 model.

OpenAI's GPT-5.6 Sol, Terra, and Luna models are now generally available on Amazon Bedrock, accessible through the OpenAI-compatible Responses API. The release introduces explicit prompt caching, letting developers manually mark cache boundaries for a 90% discount on reused input tokens.