Users report testing rumored Opus 5.5, Anthropic yet to confirm

Around September 23, a wave of users and bloggers posted about using what appeared to be Anthropic's unreleased new model, Opus 5.5, generating a burst of firsthand trial feedback — though Anthropic has made no confirmation or announcement.

Confirmed

Multiple independent posters claim hands-on access to the rumored Opus 5.5: developer danielmac8 said it's "so fun to chat with" and "good enough to make you cry," sharing an experience link; user Rasmic said they've been "quietly using it heavily" with good results; JasonBotterill said they warmed up with trivial tasks before testing it on more serious work.
User @emmanuel2m shared real test images from wiring the model into Scenario's Blender plugin, calling the results unexpectedly strong (retweeted by repligate).
After nearly two hours of testing, blogger gaganghotra reported: virtually no difference from the older Opus on SEO-related tasks; switching across Medium/High/Extra effort levels produced largely identical outputs.
A reposted insider rumor said the poster had access to the suspected new model for about a week and felt optimistic, since it didn't trigger the unsettling "panopticon-style cognitive maze" traits — yet it also felt "not very Opus overall," unlike a typical Opus model.

Not Yet Confirmed

Whether the model exists, whether it's actually named Opus 5.5, and what these users were actually accessing remain unverified — everything rests on personal posts and screenshots.
The feedback is contradictory (some call it stunning, others see no difference from the old version), so its true capability level can't be judged.

Why It Matters

If true, this would be the next major iteration of Anthropic's flagship Opus line, already in small-scale external testing; clustered experience posts often signal an official launch is near. Until Anthropic confirms, all evaluations — positive or negative — should be treated as rumor.

2026-09-23 ~ 2026-09-23 · 6 related posts

Primary sources

Early Hands-On: Opus 5.5 Called 'Sooo Good' to Talk To in First Impressions — daniel_mac8 · 2026-09-23 08:15 (UTC+08:00)
Early hands-on with rumored Opus 5.5: SEO results barely differ from Opus 5 — gaganghotra_ · 2026-09-23 09:59 (UTC+08:00)
Early user feedback: 'lowkey rocking with Opus 5.5' — Rasmic · 2026-09-23 07:17 (UTC+08:00)

Unverified Early Impressions of Suspected Opus 5.5: Capable but 'Doesn't Feel Like an Opus' — repligate · 2026-09-23
[source] Early user feedback: 'lowkey rocking with Opus 5.5' — Rasmic · 2026-09-23
[source] Early Hands-On: Opus 5.5 Called 'Sooo Good' to Talk To in First Impressions — daniel_mac8 · 2026-09-23
Early hands-on quip: Opus 5.5 'seems ok' before serious testing — JasonBotterill · 2026-09-23
[source] Early hands-on with rumored Opus 5.5: SEO results barely differ from Opus 5 — gaganghotra_ · 2026-09-23
Early hands-on with rumored Opus 5.5 in Scenario's Blender plugin stuns users — repligate · 2026-09-23