No automated migration path from the OpenAI Assistants API to the Responses API before the August 2026 sunset

Every production team running OpenAI Assistants API code must fully rearchitect to the Responses API before August 26 2026 or their apps go dark. OpenAI has confirmed no automated Thread migration tool will be provided, leaving teams to manually rewrite object models, tool definitions, state handling, and run logic across entire codebases. This CLI tool runs against a codebase, exports thread and assistant state, transforms it to the Responses API schema, rewrites SDK call sites, generates a wire-compatible shim for gradual cutover, and produces a validation diff so teams can verify correctness before flipping the switch.