#Model release

AISimon Willison says Claude Sonnet 5.5 now powers the free tier on claude.ai, so free users can run the kinds of experiments he describes. He contrasts this with ChatGPT's free tier, which he says still runs the less capable GPT-5.6 Luna.

AIDatabricks tested recent AI models across 2,400 engineers and found Opus 5.5 offers the highest quality mid-tier performance, with about 20% lower same-task costs than Opus 4.8. The company is now encouraging Opus 5.5 as a default model for coding, and reports that GPT-6 Luna is at least 20 times cheaper per task than Opus 5.5, roughly matching Opus 4.6 on one difficult evaluation suite. The Luna findings are preliminary.

AIAnthropic has released Claude Sonnet 5.5, the second model in the Claude 5.5 family. The company says it is more than 30% faster than Sonnet 5 and costs up to 30% less for most work.

Why it matters: The post gives concrete speed and price changes against Sonnet 5, which helps readers judge whether the upgrade fits their workloads and budgets.

AIAnthropic co-founder Mike Krieger says he still uses Opus 5.5 for most work, but Sonnet 5.5 is a strong complement. He praises its design skills and says he now uses it often to make Artifacts, while encouraging readers to try it.

AIAnthropic's Mike Krieger says Haiku 5.5 will round out the model family in the coming weeks. The post gives no details on capabilities, pricing, or exact release timing.

AIAnthropic has introduced Claude Sonnet 5.5, the second model in the Claude 5.5 family, as a clear upgrade over Sonnet 5. The announcement says it runs more than 30% faster and costs up to 30% less for most work. Alex Albert, quoting the announcement, says the model writes clearly, is very fast, and makes a major capabilities jump over Sonnet 5.

AIwhich links to a page for trying the model. The quoted announcement describes it as the second model in the Claude 5.5 family, a clear upgrade over Sonnet 5 that runs more than 30% faster and costs up to 30% less for most work.

AIAnthropic has released Claude Sonnet 5.5, the second model in the Claude 5.5 family. The quoted announcement says it is a clear upgrade over Sonnet 5, runs more than 30% faster, and costs up to 30% less for most work.

AIReplicate has added P-Video-2-Pro, the latest video model from Pruna AI, which sits on the edge of the preference-speed and preference-price Pareto frontiers. Design Arena ranks its Quality and Speed variants tied for #2 on the Image to Video leaderboard with an Elo of 1325, with the Quality version generating in 8.0 seconds and the Speed version in 4.5 seconds.

AIGoogle Cloud argues startups should combine open-weight models with frontier APIs rather than routing every request to one frontier model. It cites Gemma 4, which spans five sizes including a 31B dense model and a 26B A4B Mixture-of-Experts model, released under Apache 2.0. The article's examples report a 44% latency drop for Cue, from 876 ms to 488 ms, and a $0 server cost for BetterSpeak's on-device Gemma 4 E2B.

AIAnthropic has launched Claude Sonnet 5.5, the second model in its Claude 5.5 family. The company describes it as a faster, lower-cost complement to Claude Opus 5.5, and points readers to a blog post for more information.

Why it matters: The release note places Sonnet 5.5 beside Opus 5.5 in the Claude 5.5 family, clarifying which model suits speed and cost needs.

AIAmp now uses Claude Opus 5.5 for its medium mode by default, replacing GPT-5.6 Sol, while ChatGPT subscribers can keep medium pinned to GPT-5.6 Sol. In Amp's internal evals, Opus 5.5 solved 65% of tasks versus 61% for GPT-5.6 Sol and 56% for Opus 5, at lower cost, and it runs at high reasoning effort because xhigh and max cost more without scoring better.

Why it matters: The source reports internal eval scores, cost comparisons, and usage guidance for choosing reasoning effort, helping developers decide which model and setting to run.

AIMiniMax has made MiniMax-M3.1 Flash Preview available on its Token Plan, targeting teams with high-volume, latency-sensitive workloads. The model is faster and lighter, and it can be used under an existing Token Plan subscription without extra setup. MiniMax also says the text model, M3.1-Flash-Preview, debuted on MiniMax Code for everyday development tasks.

AIOpenAI released GPT-6 Sol and Luna at API prices 50% below GPT-5.6 promotional pricing, and Anthropic released Claude Opus 5.5 the same day at 40% less than Opus 5. The roundup also covers Claude Code cloud sessions reaching general availability, the Claude Marketplace launch, OpenAI's new misalignment disclosures after the Hugging Face incident, and DevDay on September 29. The post is a relayed weekly digest, and it includes the author's closing promotion for AIPRM, which is not part of the reported news.

AIAnthropic released Claude Opus 5.5 at about 40% lower cost than Opus 5, priced at $4/$20 per MTok input/output. Meta said Muse is coming to its AI glasses in the coming months, while Washington and Beijing held their first AI dialogue and discussed an incident-notification channel. The newsletter argues that costs, interfaces, experiments, and diplomacy increasingly determine how much value AI creates.

AIXiaomi has released MiMo-V2.6-Flash-MOPD on Hugging Face, an upgrade of the MiMo-V2.6-Flash-RL checkpoint that fuses several domain-specialized teachers into one model. The sparse MoE model has 309B total and 15B activated parameters, a 1M-token context length, and supports text, image, video, and audio inputs. The checkpoint targets tool-call repetition, a failure mode where the model repeatedly issues the same or similar tool calls without making progress.

AIXiaomi MiMo reports that tool-call repetition in MiMo-V2.6 reached over 0.05% of responses across agent harnesses, causing stalled agents and wasted context. The team traced the cause to an RL flooding penalty set at 32 calls per turn, which missed smaller excess behavior, and replaced the approach with a specialized teacher distilled via MOPD. Repetition rates for both Pro and Flash dropped substantially, at roughly $90,000 versus an estimated $2.31 million for the alternative fix.

Why it matters: The post traces an agent failure to a reward blind spot and compares the costs of two fixes, offering a transferable debugging method for RL-trained tool-calling models.

AIXiaomi has released MiMo-V2.6-Pro-MOPD, an upgrade of the MiMo-V2.6-Pro-RL checkpoint that fuses several domain-specialized teachers into one model via MOPD2 and targets tool-call repetition. The sparse MoE model has 1.02T total and 42B activated parameters, a 1M-token context length, and accepts text, image, video, and audio inputs. Weights are available on Hugging Face and ModelScope, with deployment recipes for SGLang and vLLM.

AIMeituan LongCat has made its LongCat-2.5-Preview model free to try on OpenCode for two weeks. The offer includes a 1M context window, multimodal support, and zero data retention.

AILongCat-2.5-Preview is free on OpenCode for two weeks, offering a 1M context window, multimodal support, and zero data retention. The post does not provide further details on pricing terms or capabilities beyond these listed features.

AIShanghai AI Lab's InternLM released Intern-Decision-4B, a multimodal structured decision model fine-tuned from Qwen3.5-4B, which returns answer distributions for multiple questions in one forward pass. On its benchmark table it scores an average of 90.02 with a Brier score of 0.347 and an ECE of 0.065, and per-query latency averages 44.16 ms on a single RTX 4090. The model is available with a Python DecisionEngine inference interface.

AIShanghai AI Lab's InternLM released Intern-Decision-2B, a multimodal structured decision model fine-tuned from Qwen3.5-2B that returns calibrated answer distributions for multiple questions in one forward pass. It averages 84.68 across listed benchmarks with a 0.437 Brier score and 33.28 ms mean latency on a single RTX 4090. Model weights, a Python DecisionEngine API, and GitHub code are available, with support for up to 16 questions and eight images.

AIInternLM released Intern-Decision-0.8B, a multimodal structured decision model fine-tuned from Qwen3.5-0.8B that scores answers to multiple questions in one forward pass. The model reports a 79.38 average score and a 33.98 ms mean latency on a single RTX 4090, with 0.8B, 2B, and 4B sizes available. It is accessed through a Python DecisionEngine API that returns calibrated probabilities rather than generating free-form text.

AIGoogle AI's weekly roundup lists Gemini 3.8 Flash TTS and Flash-Lite TTS as expressive audio generation models. It also announces Gemini 3.8 Live with Live Avatar for near real-time visual conversation and a Live Chat voice feature on the Gemini Notebook mobile app across about 100 languages. Project Suncatcher will launch a prototype satellite to test Google TPUs in orbit and explore solar-powered AI compute in space.

AIMeta has launched Muse, a personal AI assistant that can check out across shops on Shopify, with Shopify stock rising more than 10% on the news. Startup Instinct is reportedly seeking new funding at a $10 billion valuation, up from a round valuing it at $2.5 billion, while Amazon has said it will block Muse from shopping on its platform.