I tracked Claude Code and Codex pass-rates for 95 days — what "getting dumber" actually looks like
A recent analysis tracked the pass rates of Claude Code and Codex over 95 days to assess claims of declining performance. The data revealed that while Claude Code improved significantly after an update, it has recently shown a decline below its established baseline. In contrast, Codex's performance has remained relatively flat across its updates, indicating no significant improvement over time.
- ▪Claude Code's pass rate increased from 54% to 65% after an update but has recently dropped to 52%.
- ▪The decline in Claude Code's performance is statistically significant, indicating a real change rather than just perception.
- ▪Codex's performance has remained stable, oscillating between 54% and 58% across three major updates.
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| Original publisher | DEV.to (Top) |
| Canonical URL | https://dev.to/dylan_brown_4c803aefcfe51/i-tracked-claude-code-and-codex-pass-rates-for-95-days-what-getting-dumber-actually-looks-like-21le |
| Publication time | Sat, 30 May 2026 05:04:45 +0000 |
| Retrieval time | 2026-05-30T05:12:05.787Z |
| Last seen | 2026-05-30T05:12:05.787Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | kCt7LAa1-O_p |
| Cluster logic | Grouped by semantic title/content similarity across sources within a rolling window. Same-publisher template collisions are excluded from coverage comparison. |
| Ranking reason | Story pages are not engagement-ranked. Hub feeds use recency, with optional source-diversified chronological ordering (cap consecutive stories per source). No personalized ranking. |
| Publisher visit | Yes — open original |
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| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
Opening excerpt (first ~120 words) tap to expand
try { if(localStorage) { let currentUser = localStorage.getItem('current_user'); if (currentUser) { currentUser = JSON.parse(currentUser); if (currentUser.id === 3845674) { document.getElementById('article-show-container').classList.add('current-user-is-article-author'); } } } } catch (e) { console.error(e); } Dylan Brown Posted on May 30 I tracked Claude Code and Codex pass-rates for 95 days — what "getting dumber" actually looks like #programming #ai #machinelearning #productivity Every few weeks a thread blows up: "Is Claude Code getting worse?" Someone swears Opus got lazy after an update; someone else says it's placebo. The arguments are always vibes — nobody posts numbers. So I built a tracker.
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