Anthropic released Claude Opus 5.5 on September 22. Within about a week, posts began appearing on Reddit, X and GitHub saying the model had become noticeably worse than it was at launch, and a second set of complaints said Claude subscription limits were running out faster than before. This piece sets out what users have claimed, what a public third-party tracker built for this question has measured, and what Anthropic has and hasn't said. Everything below was checked at about 10:40 on October 21, Beijing time.
What users are saying
The quality complaints cluster around an outage. Claude's status page logged elevated errors across claude.ai, Claude Code, Cowork and the API starting at 22:21 on September 29, Beijing time. Hours later, at 08:57 on September 30, Reddit user juaps posted in r/ClaudeAI under the title "Opus 5.5 feels way dumber after today's outage, anyone else noticing this?" The post says the model "forgets things, makes mistakes, invents details that weren't even in the documents I gave it" and felt "like a quantized version or a completely different model." The thread drew more than 400 upvotes, and the subreddit's automatic summary described it as "pretty split down the middle," with many commenters agreeing and an equal number saying the model was working fine. A similar thread in r/ClaudeCode was titled "Opus 5.5 is Quite Degraded after the Outage."
On X, Rajath Gowda (buildwithrajath) posted at 22:28 on October 2 that "Anthropic may have NERFED Opus 5.5 BIG TIME," listing reports of the model dropping tasks, skipping commits and "claiming work is done when it isn't," while adding that it was "way too early to say." EnvolDev reran an image-style "Eiffel Tower benchmark" and wrote on October 4 that "it honestly feels like Opus 5.5 got little nerfed," though the same post says "one run doesn't prove a nerf." Not every rerun agreed. SKatalystAI repeated a coding test first run on September 22, with the same frozen repo, prompt and Cursor setup, and reported 9 of 9 both times, finishing faster and with less context, concluding "I can't reproduce the nerf."
Complaints also reached Anthropic's Claude Code issue tracker on GitHub. An issue opened by facitoo at 14:29 on October 5 says "the model quality has degraded back to level of opus 5." A commenter there, TANOSHIT, posted logs suggesting a Claude Code client update rather than the model was the cause, saying median thinking tokens per turn fell after an auto-update and that rolling back to an older client version "restores quality." That is one user's measurement, and no one from Anthropic has replied in the thread.
The usage complaints
The second complaint is about limits. Reddit user chroner wrote on September 25 that usage on a Max 5x plan was dropping "like 3 -5 times faster," while another commenter in the same thread said usage was rising unusually slowly. On GitHub, an issue opened by Dougmayfair67 at 11:05 on October 14 is titled "Opus 5.5 Usage Limits Exhausted Within 1-2 Days" and says the account was "draining between 30-50% per day" without changes to how it was used. In the same thread, leolim031 posted token counts from local Claude Code logs and argued that the five-hour session meter "got much stricter around Oct 13, while the weekly meter didn't change." These figures are users' measurements of the accounts involved. Anthropic hasn't confirmed or denied any change to how usage is metered.
What NerfBench measures
NerfBench is a test run by BridgeBench, a third-party benchmark from the developer community BridgeMind. It is not affiliated with Anthropic, and its results are an indicator, not a verdict on whether a model changed.
According to BridgeMind's published method, each run sends a model 50 coding and reasoning tasks across eight categories, three attempts each, for 150 graded attempts. Answers are single responses with no tools or repository. The headline "power" score combines correctness with output tokens and cost, and is expressed relative to the model's own launch-day run, which is set at 100%. BridgeMind treats anything between 90% and 110% as normal variance, and calls a change only when two consecutive runs fall outside that band on the same side. There are real limits. The prompts, tests and answers are private, and BridgeMind has said it won't open-source them, so nobody outside can check which tasks moved a score. Because tokens and cost feed into power, a score can fall when a model gives equally good answers at greater length. And it tracks only four models through API access, not the Claude apps or Claude Code subscriptions most complainants use, though BridgeMind has said it is adding subscription testing.
Here is what it has reported for Opus 5.5. The launch run on September 22 set the 100% baseline. The model scored 99.2% on September 27 and 103.8% on October 1, then 94.2% on October 2, which BridgeMind posted at 21:29 that day, Beijing time, writing that "94.2% is still inside normal variance, so we can't call it a nerf yet." A run on October 4 came in at 96.5%, and on October 9 BridgeBench reported 95.7%, saying Opus 5.5 was "the only model below its launch score." In its most recent weekly post, at 21:26 on October 16, BridgeBench reported Opus 5.5 at 105.8% and wrote "No nerfs detected." Every Opus 5.5 run so far has stayed inside the 90% to 110% band. A separate frontend test BridgeMind added on October 15 found Opus 5.5 using 26% more tokens on the same task than at launch, while BridgeMind judged the result "way better."
Has Anthropic responded?
Not publicly. As of about 10:40 on October 21, Beijing time, we found no statement from Anthropic on its news pages, on Claude's status page, or from the AnthropicAI, Claude or ClaudeDevs accounts on X that addresses claims Opus 5.5 got worse or that limits drain faster, and no Anthropic staff reply in the two GitHub issues above. The status page does list incidents in this period, including the September 29 outage and "Elevated errors for Claude Opus 5.5" at 20:24 on October 6, Beijing time, but those entries describe errors, not changes to model quality. What Anthropic has said on the record is in its launch post: Opus 5.5 costs less to serve than Opus 5, and it raised five-hour limits on Pro, Max, Team and seat-based Enterprise plans at launch.
How to check your own usage
If you think your allowance is draining faster, Anthropic's own tools are the place to start. On claude.ai and Claude Desktop, Settings > Usage shows progress bars for your five-hour session limit and your weekly limit, along with when each resets. Because the pool is shared, this covers Claude Code too.
Inside Claude Code, the /usage command shows the same plan usage bars. On Pro, Max, Team and Enterprise plans it adds a breakdown of recent usage attributed to skills, subagents, plugins and individual MCP servers, and it recommends changes for any behavior, such as long context or cache misses, that accounts for 10% or more of recent usage. Pressing d or w switches between the last 24 hours and the last 7 days. Anthropic notes these figures are approximate and come from local session history on that machine, so they don't include claude.ai or other devices. The Session block at the top of /usage shows token counts and a "Prompt cache (main)" line with cache misses, which matters because Anthropic's documentation says the first message after a break longer than the cache lifetime reprocesses your full context. The dollar figure in that block is meant for API users and isn't relevant to subscription billing, according to Anthropic. If usage credits are on, /usage also shows your credit spend for the month.
Anthropic's cost guide lists the common reasons usage climbs in long sessions, including long context, cache misses, scheduled tasks, subagents and compaction. For billing questions about a specific account, Anthropic points subscribers to Get help in the claude.ai menu.
Our explainer "Anthropic Still Describes Claude Code Limits in Multiples, So Here's What Each Plan Gets" covers how the five-hour and weekly limits work on each plan.