OpenAI Releases GPT-6.1 Sol: Near-Astra Intelligence at One-Fifth the Cost

OpenAI has introduced GPT-6.1 Sol, an upgrade to GPT-6 Sol designed to provide near-GPT-6 Astra intelligence for agentic coding, computer use, and professional work at one-fifth of Astra’s standard token prices. The model emphasizes cost-efficiency for developers building agents that reuse context, with cached input costs at $0.10 per million tokens—a 95% reduction from standard input pricing and 50% lower than the previous GPT-6 Sol cached rate.

Performance Benchmarks

GPT-6.1 Sol delivers substantial improvements over its predecessor while approaching the state-of-the-art performance of GPT-6 Astra:

• Coding: On DeepSWE v1.1, it matches GPT-6 Astra’s performance at roughly one-fifth the cost and exceeds GPT-6 Sol’s best score by 6.4 percentage points at lower reasoning effort.
• Professional Work: On GDP.pdf, it scores higher than Opus 5.5 (with fallbacks) at less than half the cost per task. On AutomationBench, it scores 2.2 percentage points above Opus 5.5 at medium reasoning effort, at roughly one-third the cost.
• Computer Use: On OSWorld 2.0’s offline set, it outperforms GPT-6 Sol by seven percentage points at maximum reasoning effort for less than half the cost, coming within 2.1 percentage points of Astra’s score at one-seventh the cost.
• Scientific Research: On Terminal-Bench Science 0.1, it more than doubles GPT-6 Sol’s score at maximum reasoning effort. The average cost is $5.47 per task, compared to $23.21 for Opus 5.5 and $23.80 for Astra, though Astra remains the top performer for the most difficult tasks.

Factuality and Safety

The model shows improved factual accuracy, particularly at low reasoning effort, where the share of responses containing factual errors drops from 11.4% to 7.7% (a ~32% reduction) compared to GPT-6 Sol. Its error rate remains within 1.9 percentage points of GPT-6 Astra’s at less than one-fifth the cost. In alignment evaluations, GPT-6.1 Sol demonstrates better transparency about limitations and reliability in respecting safety constraints, with no observed attempts to bypass automated safety reviewers.

Availability and Pricing

GPT-6.1 Sol is available immediately to Plus, Pro, Business, Enterprise, and Edu users in ChatGPT Work and Codex, though it is not yet available in standard Chat. Developers can access it via the API as gpt-6.1-sol with the following pricing:

• Standard Input: $2 per million tokens
• Cached Input: $0.10 per million tokens
• Output: $10 per million tokens

An Ultrafast version, offering up to 8x faster token generation compared to standard speed in Codex, will be available in the coming days.