GPT-5.6 Luna
5 storiesGPT-5.6 Luna is a model in OpenAI's GPT-5.6 line. Recent coverage focuses on coding and decision benchmarks: on the SWE-Race concurrency-bug benchmark it scored 81% with one attempt, behind GLM-5.3 Flash at 85%, and in a 50-PR code review comparison it found 69 verified bugs at $0.20 versus 92 for GPT-6 Astra at $5.66. A developer also reported local models beating Luna on some tasks after Codex CLI configuration.
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Developers built Gear, an open-source meta-learning framework aiming to be a scikit-learn for RSI. In benchmarks, Gear-optimized DSH improved pass rates from 27.0% to 40.0% on AutomationBench Marketing and from 52.8% to 62.9% on Terminal-Bench 2.1.
Researchers built SWE-Race, a benchmark of 188 real concurrency bugs from merged PRs in about 100 Python projects, graded by each project's own tests in an offline container. With one attempt, GLM-5.3 Flash scored 85% and GPT-5.6 Luna 81%; simple tasks near 100%, with differences mainly on the harder half.
A business consultant spent 15 days fine-tuning a Qwen3.5-4B model with LoRA and a small decision head to create ImaJev-4B, which handles text and up to two images and returns probabilities per option. It ranked #1 of 91 on JevBench (67.37) and #3 of 56 on DecisionBench, ahead of GPT-5.6 Luna and DeepSeek V4.1. Total cost about $1,200; weights released under Apache-2.0.
A user reports that configuring Codex CLI with GPT's help let local Qwen 3.8 Flash Next outperform GPT 5.6 Luna on a 3D Mario test and a real project, after local models had long lagged in serious work. The user also ported a search tool into Codex as a skill.
In a 50-PR comparison, GPT-5.6 Luna found 69 verified bugs while GPT-6 Astra found 92; Luna run cost $0.20 versus Astra $5.66. Luna is much cheaper and handles routine correctness bugs well but has more false findings and finds fewer security issues, so it shouldn’t be sole reviewer for security-sensitive code.
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