OpenAI Releases GPT-5.6 Sol Pro with Extended Reasoning Mode

OpenAI has released GPT-5.6 Sol Pro, a reasoning-optimized version of its GPT-5.6 Sol model that automatically applies extended reasoning to complex tasks. The model became available through OpenRouter on July 9, 2026.

Technical Specifications

GPT-5.6 Sol Pro runs on the same underlying architecture as GPT-5.6 Sol but operates with reasoning mode set to "pro" by default. The model features:

• Context window: 1 million tokens
• Knowledge cutoff: February 2026
• Pricing: $5 per 1M input tokens, $30 per 1M output tokens
• Modalities: Text input and output

According to OpenRouter, the model is specifically tuned for "higher-quality responses on complex tasks" compared to the standard GPT-5.6 Sol variant.

Pricing and Availability

The model's output pricing of $30 per 1M tokens represents a 6x markup over input costs, reflecting the additional computational overhead of extended reasoning. OpenRouter reports that customers typically pay 60-80% less than list prices due to prompt caching on repeated context.

The model is currently available through a single provider via OpenRouter's API, which maintains OpenAI compatibility for drop-in replacement with existing SDKs.

Deployment Details

OpenRouter's monitoring shows the model's uptime percentage over the past 30 days, along with throughput metrics (tokens per second) and latency measurements including time-to-first-token (TTFT). The platform automatically retries failed requests on alternative providers when errors occur.

What This Means

GPT-5.6 Sol Pro represents OpenAI's strategy of offering reasoning-optimized variants alongside standard models, similar to the approach taken with o1 and o3 series models. The 1M token context window positions it for document analysis and extended conversations, though the 6x output pricing premium suggests OpenAI expects the reasoning overhead to justify the cost for complex problem-solving tasks. The February 2026 knowledge cutoff indicates this release incorporates relatively current training data, though verification of model capabilities beyond OpenAI's claims awaits independent benchmarking.