GPT-6.1 Terra

GPT-6.1 Terra, which OpenAI released on October 26, 2026, is the fast, cheaper member of the GPT-6.1 family, built for computer use, reading images and writing, at $1 / $5 per million tokens, half the price of GPT-5.6 Terra and GPT-6.1 Sol.

The benchmarks

OpenAI charted every model at every effort setting, priced per task. The rows below are GPT-6.1 Terra at max effort against each rival's max-effort score. At medium effort Terra scores 57.6% on Agents' Last Exam v1, the same as GPT-6 Astra at medium, for $0.29 a task against $4.82. Opus 5.5's Terminal-Bench Science score was run with fallbacks. OpenAI's factuality test is its own set of prompts that tend to cause errors, so lower is better there.

OpenAI's numbers

• Agents' Last Exam v1 (professional work on a computer, max): 60.0%. +9.3 over GPT-5.6 Terra at max (50.7%), +1.4 over GPT-6.1 Sol at max (58.6%), +0.7 over GPT-6 Astra at max (59.3%), +9.1 over GPT-6 Luna at max (50.9%), −3.2 under Claude Opus 5.5 at max (63.2%).

• OSWorld 2.1 (using desktop apps, max): 74.2%. +17.1 over GPT-5.6 Terra at max (57.1%), −3.8 under GPT-6.1 Sol at max (78.0%), −6.7 under GPT-6 Astra at max (80.9%), +18.7 over GPT-6 Luna at max (55.5%), −9.7 under Claude Sonnet 5.5 at max (83.9%).

• MMMU-Pro Vision (reasoning over images, max): 85.5%. +3.8 over GPT-5.6 Terra at max (81.7%), −0.8 under GPT-6.1 Sol at max (86.3%), −1.2 under GPT-6 Astra at max (86.7%), +5.6 over GPT-6 Luna at max (79.9%).

• Terminal-Bench 4.0 (coding in a terminal, max): 50.3%. +28.8 over GPT-5.6 Terra at max (21.5%), −5.6 under GPT-6.1 Sol at max (55.9%), −7.9 under GPT-6 Astra at max (58.2%), −20.3 under Claude Sonnet 5.5 at max (70.6%).

• Terminal-Bench Science 0.1 (science tasks in code, max): 58.3%. +1.3 over GPT-6.1 Sol at max (57.0%), −9.8 under GPT-6 Astra at max (68.1%), −5.0 under Claude Opus 5.5 at max (63.3%).

• Factual error rate (OpenAI's hard prompts, lower is better, max): 4.3%. −18.0 under GPT-5.6 Terra at max (22.3%), −0.1 under GPT-6.1 Sol at max (4.4%), +0.1 over GPT-6 Astra at max (4.2%), −14.1 under GPT-6 Luna at max (18.4%).

Independent numbers

Artificial Analysis posted its numbers minutes after launch. Its chart shows whole numbers for Terra at max effort; rival scores are rounded from Artificial Analysis's model pages.

• Artificial Analysis Intelligence Index (v4.3.2, max): 48. +6 over GPT-5.6 Terra at max (42), −4 under GPT-6.1 Sol at max (52), +10 over GPT-6 Luna at max (38), −8 under Claude Sonnet 5.5 at max (56), +5 over Claude Haiku 5.5 at max (43).

• Artificial Analysis Coding Agent Index v2.0 (coding agents in their own harness, max): 48. −6 under GPT-6.1 Sol at max (54), +17 over GPT-6 Luna at max (31), −11 under Claude Sonnet 5.5 at max (59), −14 under Claude Opus 5.5 at max (62).

• AA-Omniscience hallucination rate (guessing when it doesn't know, lower is better): 38%. −50 under GPT-5.6 Terra (88%).

First impressions

Terra is a few hours old. Reactions come from X and the Hacker News launch thread.

The positives

Artificial Analysis (@ArtificialAnlys), which runs the same tests on every model, had its results up five minutes after OpenAI's post.

Their read backs OpenAI's pitch where it counts for a cheap model: the low and medium settings are the best value on their chart, and it guesses far less often when it doesn't know an answer. At max effort it still sits below GPT-6.1 Sol.

Devansh (@thenowhereway), a general X user, did the math on OpenAI's computer-use chart.

That's OpenAI's chart, not a test they ran, but it's the case for Terra in one line: close to Opus 5.5 on computer work for about a ninth of the bill.

A_D_E_P_T on Hacker News had the same first read.

Wow. If those charts are true, this effectively matches GPT-6-Astra at a fraction of the cost, and is neck-and-neck with 6.1-Sol. (comment)

Artificial Analysis has it a few points under both, so "neck-and-neck" holds on OpenAI's computer-use test more than across the board.

The negatives

minimaxir on Hacker News pointed at the coding chart.

The TerminalBench 4.0 cost-per-task results are a bit confusing and I'm not sure why you would pick Terra over Sol in that case. (comment)

OpenAI's own chart backs this up: Sol on its lowest setting beats Terra on its second-highest, for less money per task. Starlevel004 made the same point. For coding, Sol is the better buy.

Angel (@Angaisb_), a general X user, summed up a lot of the launch-hour replies.

The loudest complaint isn't about Terra itself. People want an OpenAI model that beats Opus 5.5, and this one isn't trying to.

Robert Beall (@RobertBeall17), a general X user, couldn't get it working in Codex 18 minutes after launch.

One person on launch day with no details, so treat it as a flag, not a verdict: try it in Codex before you switch your defaults.