Claude Code didn't get worse. The harness did. And that ends one of the most common AI complaints of 2026.
Recent complaints about the Claude Code AI model's performance have been attributed to changes in its operational harness rather than the model itself. Anthropic's postmortem revealed that three regressions affected user experience without altering the model weights. This incident highlights the importance of treating the AI harness as a critical component of product reliability.
- ▪Anthropic identified three regressions that degraded user experience without changing the model weights.
- ▪The regressions included downgrading reasoning depth, a caching bug, and a strict brevity instruction.
- ▪The incident emphasizes the need for AI product teams to evaluate changes in the harness with the same rigor as code changes.
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try { if(localStorage) { let currentUser = localStorage.getItem('current_user'); if (currentUser) { currentUser = JSON.parse(currentUser); if (currentUser.id === 211299) { document.getElementById('article-show-container').classList.add('current-user-is-article-author'); } } } } catch (e) { console.error(e); } Anil Kurmi Posted on May 16 Claude Code didn't get worse. The harness did. And that ends one of the most common AI complaints of 2026. #ai #anthropic #engineering #devtools For two months, the same complaint kept showing up on every developer forum I read: Claude Code feels worse. Sometimes worded politely, sometimes not. The vibe was unanimous enough that I almost started believing it on reputation alone.
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