OpenAI: GPT-5.5 Pro

GPT-5.5 Pro is a paid model from OpenAI that accepts text, images, and file uploads, making it suitable for document-heavy or multimodal workflows. It offers a 1,050,000-token context window and up to 128,000 completion tokens, and it supports both tool use and reasoning, giving it flexibility for agentic and multi-step tasks. Structured output support is unconfirmed based on currently available specifications. At $30.00 per million input tokens and $180.00 per million output tokens, this is an expensive option, and there is currently no independent benchmark coverage to justify that cost on performance grounds. Teams with budget flexibility who need long-context multimodal processing and reasoning capabilities may find it worth evaluating, but anyone prioritizing cost efficiency or wanting verified benchmark comparisons before committing should treat it as unproven for now and weigh it against lower-priced alternatives with documented scores.