GPT-5.6 Terra vs PaliGemma

GPT-5.6 Terra is the mid-tier reasoning model in OpenAI's GPT-5.6 family, which also includes the flagship Sol and the lightweight Luna. Introduced in a limited preview on June 26, 2026, and made broadly available on July 9, 2026, Terra accepts text and image input and produces text output, supporting vision, function calling, tool use, and agentic workflows. It is designed as a balanced option for everyday professional and production workloads — including coding assistance, document analysis, customer support, and multi-step agent tasks — where both output quality and cost efficiency matter. OpenAI positions Terra as delivering performance competitive with GPT-5.5 at approximately half the price, with a context window of around 1,050,000 tokens. On Terminal-Bench 2.1, Terra scores 84.3%, matching Claude Fable 5 on that benchmark. Under OpenAI's Preparedness Framework, Terra is rated High for cybersecurity and biological capabilities, meaning it demonstrates meaningful capability in those domains without reaching the Critical threshold.

GPT-5.6 introduces a new naming convention in which the generation number (5.6) is paired with a durable capability tier name (Sol, Terra, or Luna), allowing each tier to advance on its own schedule. Terra carries the API identifier gpt-5.6-terra and supports the same reasoning effort controls available across the family, including adjustable reasoning depth. The model includes prompt caching with explicit cache breakpoints and a 30-minute minimum cache life, with cache writes billed at 1.25x the uncached input rate and cache reads receiving a 90% discount. GPT-5.6 Terra is a proprietary, closed-weights model served through the OpenAI API, Codex, and ChatGPT.

PaliGemma is a vision-language model released in May 2024 by Google, built by pairing the SigLIP-So400m vision encoder with the Gemma 2B language model. It is designed primarily as a compact, transfer-friendly base model for fine-tuning to downstream vision-language tasks, rather than as a chat-optimized assistant. PaliGemma draws architectural inspiration from the PaLI-3 model at Google Research, applying a similar encoder-decoder approach at a smaller and more accessible parameter scale.

PaliGemma accepts an image together with a text prompt and generates text output, supporting image captioning, visual question answering, optical character recognition, object detection, referring expression segmentation, and a range of related vision-language tasks when fine-tuned on task-specific data. The model is released at three input resolutions (224, 448, and 896 pixels), with higher resolutions providing stronger performance on tasks requiring fine visual detail such as OCR and document understanding. Google released pretrained (PT) checkpoints intended as fine-tuning bases, along with Mix variants that have been fine-tuned on a mixture of downstream tasks for direct use without additional training. PaliGemma is distributed under the Gemma license, a custom license from Google that permits commercial use subject to the terms of the Gemma Prohibited Use Policy. It was succeeded by PaliGemma 2 in December 2024, which extends the architecture to larger Gemma 2 language backbones at 3B, 10B, and 28B parameter sizes.