Use a fixed GPT-5.5 snapshot in a controlled Responses API tool loop with reasoning policy, validation, idempotent execution, and recoverable checkpoints.
Evaluate GPT-5.5 on frozen tasks, hidden acceptance, tool traces, blinded review, and total task cost after its April 2026 API availability.
Let OpenAI, Anthropic, and Gemini adapters own their structured-output parameters while mapping into one versioned domain schema and error model.
Turn Qwen3 hybrid thinking into a task router with bounded time and tokens, paired evaluation, deterministic verification, and explicit fallback.
Evaluate Mistral Small 4 for constrained tool routing while accounting for open weights, configurable reasoning, strict validation, and its real infrastructure floor.