Anthropic says it has fixed three recent Claude Code quality issues: reduced default reasoning, a caching bug, and a system prompt change to reduce verbosity
Anthropic
Context & Ripple Effects
Recent user complaints about Claude Opus 4.6 and Claude Code performance had prompted public denials that Anthropic was intentionally reducing model quality to manage capacity. Anthropic now identifies operational and product-configuration causes instead: lower default reasoning, a caching fault, and a prompt-level change aimed at shorter answers.
This follows Anthropic’s earlier disclosure of intermittent infrastructure bugs affecting Claude responses, making reliability and transparent incident explanation a recurring issue for the company’s developer-facing products.
First-order effects
Claude Code users should see more consistent reasoning behavior, corrected cache handling, and less distortion from the verbosity-oriented system-prompt change.
Anthropic has publicly tied the reported quality regression to identifiable settings and bugs rather than deliberate capacity management, directly addressing the recent user dispute.
Second-order effects
Developers evaluating Claude Code will have another reason to distinguish model capability from the serving, caching, and prompt-layer configuration that shapes production behavior.
The episode raises the value of regression monitoring for AI coding tools: competitors and enterprise buyers will scrutinize consistency across updates, not just headline model releases.
Third-order effects
As AI products add configurable reasoning budgets and system-level behavior controls, perceived model quality will increasingly depend on operational reliability as much as on the underlying model.
Repeated public incident explanations could make transparency around model changes and service regressions a stronger competitive expectation, though it remains unclear whether providers will standardize such disclosure.
The trend: This is part of the shift from treating AI quality as a static model attribute to treating it as an operational outcome of inference settings, infrastructure, and product-layer controls.
Over the past month, some of you reported Claude Code's quality had slipped. We investigated, and published a post-mortem on the three issues we found. All are fixed in v2.1.116+ and we've reset usage limits for all subscribers.
The most ridiculous part of this is that Anthropic employees were repeatedly in people's X mentions, gaslighting customers and telling them they were wrong.
We're making changes to catch these types of issues earlier, including more internal dogfooding with configs that exactly match those of our users and creating a broader set of evals and running them against isolated system prompt changes
The issues stemmed from Claude Code and the Agent SDK harness, which also impacted Cowork since it runs on the SDK. The models themselves didn't regress, and the Claude API was not affected.
it's wild that they did not acknowledge this the entire time - Boris even went around saying nothing was wrong! Laughable company, be very curious to see if this fixes stability issues
Anthropic has tracked down and fixed why Claude seems to have gotten dumber in the past month. — 1. Reduced default reasoning effort (from High to Medium). — 2. A caching bug that accidentally deleted Claude's memory mid-session. — 3. A system prompt change for verbosity th…