> ## Content Index > Fetch the complete content index at: https://www.testingcatalog.com/llms.txt > Use this file to discover other available public pages before exploring further. # Anthropic tests its next model under Claude Opus 5.5 - URL: https://www.testingcatalog.com/anthropic-tests-new-model-opus-5-5-routing-opus-5-6-fable-5-5/ - Published: 2026-10-12T13:11:16.000Z - Updated: 2026-10-12T14:10:14.000Z - Description: Some Claude users say their Opus 5.5 requests are landing on a new, unannounced model, and the outputs shared on X so far look like a real step up. Whether it ends up as Opus 5.6 or Fable 5.5 is still unclear. - Author: Dwaybe Cubbins - Tags: Anthropic, AI Rumours, Latest AI News Anthropic appears to be quietly testing another model in the wild. Over the weekend, several users on X noticed Claude Opus 5.5 producing results well beyond its usual level, suggesting some of that traffic is being routed to a new checkpoint. Interestingly, this comes just three weeks after [Anthropic launched Opus 5.5](https://www.testingcatalog.com/anthropic-launches-claude-opus-5-5-with-lower-api-costs/) with lower API costs. 0:00 /0:28 1× In our tests, this new model delivered a SOTA output with the best depth and level of details X user [can](https://x.com/marmaduke091?ref=testingcatalog.com) was among the first to spotlight the potential new model in testing. They shared a recording of the output they got from a single-sentence prompt that had the model use Blender's MCP. Here's the stunning result: > 🚨 Claude-next model ONE SHOT > > This is with just a simple one sentence prompt. It worked for 2 hours with Blender MCP to create it from scratch, no ready made model was used. > > This is the single most impressive output I've got from a model so far. [pic.twitter.com/qIKUjYJbiB](https://t.co/qIKUjYJbiB?ref=testingcatalog.com) > > — can (@marmaduke091) [October 11, 2026](https://x.com/marmaduke091/status/2109396343114666207?ref%5Fsrc=twsrc%5Etfw&ref=testingcatalog.com) Kol Tregaskes [noted](https://x.com/koltregaskes/status/2109288430857507154?ref=testingcatalog.com) that Opus 5.5 seems to be routing to a new checkpoint "again" and shared a quick check: ask Opus 5.5, "Do you know VoxelBench? Do not search." If it answers, you're probably on the new model. This mainly boils down to fresh training data, not a smarter model per se. Still, it's not just a couple of users claiming that they've encountered the new model. Another one, [@kimmonismus](https://x.com/kimmonismus/status/2109300315669565612?ref=testingcatalog.com), said their requests seem to be hitting the new model, wondering whether it's a fresh Opus 5.5 checkpoint or something like Opus 5.6, and added that it *"looks really, really good."* [Chetaslua](https://x.com/chetaslua?ref=testingcatalog.com) also shared an animation called "The life of a Human" with every frame drawn in JavaScript. According to the post, it took two short prompts, about two hours, and roughly 27 million tokens at max thinking effort. He also mentioned that it could be Fable 5.5 or a new Opus model, possibly Opus 5.6. > 🚨 Claude Next is being tested on claude code > > and i thought it will take a month to make image and video gen model obsolete i was wrong > > Behold the supremacy , fully coded ,this akes even Opus 5.5 look primitive > > I will upload more test different types its SOTA in every f#ing… [https://t.co/AS5C5WXj6z](https://t.co/AS5C5WXj6z?ref=testingcatalog.com) [pic.twitter.com/6v22g50dph](https://t.co/6v22g50dph?ref=testingcatalog.com) > > — Chetaslua (@chetaslua) [October 11, 2026](https://x.com/chetaslua/status/2109290983896818132?ref%5Fsrc=twsrc%5Etfw&ref=testingcatalog.com) He then shared another "Claude Next" demo, claiming the coded visuals are good enough to rival image and video generators. Someone else also followed up with a 3D scene the model reportedly built from scratch with Blender MCP after a single-sentence prompt, working for two hours without ready-made assets, and called it the most impressive output they've had from any model. > Opus 5.5 is apparently routing to newer model > > I don't notice too crazy of a difference, the one routing maybe looks a little better imo > > I ran this multiple times to account for it being random too and this was the best, what do you think ? [pic.twitter.com/yRlzcYnbwn](https://t.co/yRlzcYnbwn?ref=testingcatalog.com) > > — Lumina (@LuminaBench) [October 11, 2026](https://x.com/LuminaBench/status/2109333268881694751?ref%5Fsrc=twsrc%5Etfw&ref=testingcatalog.com) There's a slight chance this is Fable 5.5, or whatever label Anthropic settles on. But since it's routing to Opus 5.5, an Opus 5.6 test seems at least as likely. Either way, the early results are incredible. Anthropic has kept up a fast pace lately, shipping Sonnet 5.5 and Haiku 5.5 in the past couple of weeks, and [building its own voice models](https://www.testingcatalog.com/anthropic-might-be-developing-its-own-voice-models/). > Me and [@chetaslua](https://x.com/chetaslua?ref%5Fsrc=twsrc%5Etfw&ref=testingcatalog.com) just asked Fable 5.5 to create a song introducing itself, and it made a full-blown religious musical called “Hosanna,” with the model singing its own introduction. > > It used my Suno for the music, ElevenLabs for the vocals, and built a synchronized Three.js… [pic.twitter.com/69FKrEWsqW](https://t.co/69FKrEWsqW?ref=testingcatalog.com) > > — Chris (@ChrisGPT) [October 12, 2026](https://x.com/ChrisGPT/status/2109570757579649086?ref%5Fsrc=twsrc%5Etfw&ref=testingcatalog.com) Opus 5.5 already costs $4 and $20 per million input and output tokens. If Anthropic can bring this level of output at a similar price, it would be a game changer. OpenAI recently [pushed GPT-6.1 Sol](https://www.testingcatalog.com/openai-launches-gpt-6-1-sol-at-one-fifth-of-astra-pricing/) to near-Astra performance at one-fifth of the price, and Google has [Gemini 4 Argon showing up in A/B tests](https://www.testingcatalog.com/gemini-4-argon-ab-tests-early-outputs/), but OpenAI in particular will have to put its best foot forward to keep up. > The best is yet to come. Stay tuned peeps [https://t.co/xE0oAFFjIi](https://t.co/xE0oAFFjIi?ref=testingcatalog.com) > > — John Hoffmann (@johnjhoffmann) [October 11, 2026](https://x.com/johnjhoffmann/status/2109406382302888266?ref%5Fsrc=twsrc%5Etfw&ref=testingcatalog.com) John Hoffmann, Partnerships & Outreach Manager at Anthropic, has commented on these outputs recently: *"The best is yet to come. Stay tuned, peeps."* Yet the model name and timing remain open. If you use Opus 5.5, you might already be trying it.